Background: Denture fracture is one of the most common problems encountered by the patients and prosthodontists. The objective of present study was to evaluate the transverse strength of nylon denture base resin repaired by using conventional heat polymerized, autopolymerized and visible light cure {VLC} resins, surface treatment that used for repair and adjustment of insufficient nylon denture bases and in case of addition of artificial teeth. As these corrective procedures are common chair side procedures in dental clinic. Materials and methods: One hundred twenty nylon specimens were prepared by using metal patterns with dimension of (65x10x2.5 mm) length, width, and thickness respectively for transverse strength test while for tensile bond strength a dumbbell-shaped with measurement (65x12.5x25mm) length, width, and thickness respectively were flasked with stone. The nylon specimens were molded by reflasked with dental stone that used as an index for these specimens in the repair procedure and repaired with 45 degree bevel joint by using metal holding device. The two parts of nylon specimen to be repaired were realigned in its repair index and adhere with special adhesive material to stabilize the combination during repair procedure. The dough of heat and cold cure resin was packed into the joint and then cured. The specimen repaired with cold cure resin was placed in the Ivomat containing water at (40°C) and pressure (30IB/inch²) for 15 minutes. The specimen repaired with {VLC} was placed in the light cure unit for 4 minutes following manufacturer’s instruction. The fractured nylon specimens were divided according to the type of repaired materials into (40) specimens received heat cure acrylic and the (40) specimens received cold cure acrylic and the other 40 specimens received {VLCR}. Each 40 specimens were subdivided according to the type of surface treatment received into 20 specimens were treated with coarse stone bur (control), 20 specimens were treated with combination of coarse stone bur and monomer of the heat cure acrylic. After that the specimens were subjected to transverse {Tr} and tensile bond {TB} strength tests. For each test 10 specimens. Results and conclusions: This study showed that specimens treated with combination of coarse stone bur and monomer of the acrylic (heat, cold or VL cure) had the highest transverse and tensile strength values, followed by the specimens treated with coarse stone bur. The results showed that the specimens repaired with heat cure acrylic had transverse and tensile strength values higher than the specimens repaired with cold and VL cure acrylic when compared between subgroups of heat, cold and VL cure acrylic that received the same treatments.
Image segmentation can be defined as a cutting or segmenting process of the digital image into many useful points which are called segmentation, that includes image elements contribute with certain attributes different form Pixel that constitute other parts. Two phases were followed in image processing by the researcher in this paper. At the beginning, pre-processing image on images was made before the segmentation process through statistical confidence intervals that can be used for estimate of unknown remarks suggested by Acho & Buenestado in 2018. Then, the second phase includes image segmentation process by using "Bernsen's Thresholding Technique" in the first phase. The researcher drew a conclusion that in case of utilizing
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The present work aims to study the possibility of utilization a forward osmosis desalination process as an alternative method to extract water from brine solution rejected from reverse osmosis process.
Experiments conducted in a laboratory–scale forward osmosis (FO) unit in cross flow flat sheet membrane cell yielded water flux ranging from (0.0315 to 0.56 L/m2 .min) when using CTA membrane,and ranging from (0.419 to 2.785 L/m2 .min) for PA membrane under 0.4 bar. Two possible membrane orientations were tested. Sodium chloride with high concentrations was used as draw solution solute. The effect of membrane orientation on internal concentration polarization (ICP) was studied. Two regimes of ICP; dilutive and concentrative were desc
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Gypseous soils are common in several regions in the world including Iraq, where more than 28.6% of its surface is covered with this type of soil. This soil, with high gypsum content, causes different problems for construction and strategic projects. As a result of water flow through the soil mass, the permeability and chemical arrangement of these soils varies with time due to the solubility and leaching of gypsum. In this study, the soil of 36% gypsum content, was taken from one location about 100 km southwest of Baghdad, where the samples were taken from depths (0.5 - 1) m below the natural ground and mixed with (3%, 6%, 9%) of Copolymer and Novolac polymer to improve the engineering properties that include: collapsibility, perm
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Large quantities of contaminated carwash wastewater are produced per day from carwash places. Extensively it contains large quantities of chemicals from detergents, oil, grease, heavy metals, suspended solids, types of hydrocarbons, and biological contents. A novel electrocoagulation treatment by foil electrodes was conducted to remove COD, turbidity, Total Dissolved Solids (TDS) from contaminated carwash wastewater and decrease its Electrical Conductivity (EC). A thin layer of aluminum foil is used as an electrode in this treatment process. The effects of different voltage and treatment times were studied. The best result was found at a voltage of 30 volts and treatment time 90 minute where the removal efficiency of COD
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In this paper, the generation of a chaotic carrier by Lorenz model
is theoretically studied. The encoding techniques has been used is
chaos masking of sinusoidal signal (massage), an optical chaotic
communications system for different receiver configurations is
evaluated. It is proved that chaotic carriers allow the successful
encoding and decoding of messages. Focusing on the effect of
changing the initial conditions of the states of our dynamical system
e.i changing the values (x, y, z, x1, y1, and z1).
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Many undergraduate learners at English departments who study English as a foreign language are unable to speak and use language correctly in their post -graduate careers. This problem can be attributed to certain difficulties, which they faced throughout their education years that hinder their endeavors to learn. Therefore, this study aims to discover the main difficulties faced by EFL students in language learning and test the difficulty variable according to gender and college variables then find suitable solutions for enhancing learning. A questionnaire with 15 items and 5 scales were used to help in discovering the difficulties. The questionnaire was distributed to the selected sample of study which consists of 90 (male and female) stud
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Copper nanoparticles (CuNPs) were prepared with different diameters by sonoelectrodeposition technique using Electrodeposition process coupled with high-power ultrasound horn (Sonoelectrodeposition). The particle diameter of the CuNPs was adjusted by varying CuSO4 solution acidity (pH) and current density. The morphology and structure of the CuNPs were examined by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). It was found that the size of the produced copper nanoparticles ranged between 22 to 77 nm, where the diameter of CuNPs increases with reduction the solution acidity from 0.5 to 1.5 pH and increasing the current density of the deposition from 100 to 400 nm. Finally the produced CuNPs were pressed to fabricate disc
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