Background: Studying and investigating the transverse strength(Ts), impact strength(Is), hardness (Hr) and surface roughness(Ra) of conventional and modified autopolymerizing acrylic resin with different weight percentages of biopolymer kraftlignin, after curing in different water temperatures; 40°C and 80°C. Material and Methods: Standard acrylic specimens were fabricated according to ADA specification No.12 for transverse strength, ISO 179 was used for impact testing, Shore D for hardness and profilometerfor surface roughness. The material lignin first dispersed in the monomer, then the powder PMMA is immediately added. Ligninadded in different weight percentages. Then cured using pressure pot (Ivomet) in two temperatures;40°C and 80°C under 2 bar pressure, for 30 minutes.Atotal of 144samples were prepared for this study. Ts, Is, Ra, and Hr were tested, by using Instron universal testing machine, charpy impact tester, shore D tester, and profilometer respectively. Results: The transverse strength increased in both the conventional and modified onewhen compared with that cured in air. The addition of 0.5wt% lignin gave the higher effect (78.0017MPa) with highly significant difference found between groups at 40°C polymerizing temperature. While the impact strength in both temperatures in the modified resin revealed increased results than conventional one, 1.25wt% of kraft lignin gave the highest value (12.7355KJ/m2) with highly significant differences found between groups at 80°C polymerizing temperature. Hardness and surface roughness showed also highly significant differences found between groups at 40°C polymerizing temperature, all the groups had increased Hr. than the control one (78.95), while the Ra. decreased for 1.0% ,1.25,1.50 and 1.75 wt% lignin content to (0.26,0.10,0.063, 0.12µm) respectively in 40°C polymerizing temperature, the lowest value present in 1.75 wt% lignin (0.05 µm) at 80°Cpolymerizing temperature. Conclusions: It seems that increasing the polymerizing temperature to 40°C had a positive effect on the mechanical properties of autopolymerizing acrylic resin and the one enforced by kraft lignin biopolymer in low percentages. Increasing the polymerizing temperature to 80°C will doesn’t have much positive effect but it doesn’t deteriorate the mechanical properties. However, when submitted to increasing the temperature to 80°C, specimens showed a significant increase in impact strength.
lar water heating systems with heat pipes of three diameter groups of 16, 22 and 28.5 mm. The first and third groups had evaporator lengths of 1150, 1300 and 1550 mm. The second group had an additional length of 1800 mm. all heat pipes were of fixed condenser length of 200 mm. Ethanol at 50% fill charge ratio of the evaporator volume was used as the heat pipes working fluid. Each heat pipe condenser section was inserted in a storage tank and the evaporator section inserted into an evacuated glass tube of the Owens- Illinois type. The combined heat pipe and evacuated glass tube form an active solar collector of a unique design.
The resulting ten solar water heating systems were tested outdoors under the meteorological conditions of Bag
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Background: Knowledge about the prevalence and distribution of pathologies in a particular location is important when a differential diagnosis is being formulated. The aim of this study was to describe the prevalence and the clinicopathological features of odontogenic cysts and tumors affecting the maxilla and to discuss the unusual presentation of those lesions within maxillary sinus.
Materials and Methods: A multicenter retrospective analysis was performed on pathology archives of patients who were diagnosed with maxillary odontogenic cysts and tumors from 2010 to 2020. Data were collected with respect to age, gender and location.
Result: A total of 384 cases was identified, 320 (83.3%) cases were diagnosed as odontogenic
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An encryption system needs unpredictability and randomness property to maintain information security during transmission and storage. Although chaotic maps have this property, they have limitations such as low Lyapunov exponents, low sensitivity and limited chaotic regions. The paper presents a new improved skewed tent map to address these problems. The improved skew tent map (ISTM) increases the sensitivity to initial conditions and control parameters. It has uniform distribution of output sequences. The programs for ISTM chaotic behavior were implemented in MATLAB R2023b. The novel ISTM produces a binary sequence, with high degree of complexity and good randomness properties. The performance of the ISTM generator shows effective s
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Abstract
Objective(s): To evaluate high school male students' knowledge about substance use, to determine the effectiveness of the education program on high school mal students' knowledge about substance use.
Methodology: A quasi-experimental (pre-posttest) design was carried out to determine the effectiveness of an educational program on knowledge of high school students about substance use in AL-Kut city. The study was started from 20th h September 2022 to 24th November 2022. The sample was non-probability (purposive sample) sample of (60) student were selected according to the study that are working in Al Kut Education Directo
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Alpha-tocopherol acetate is one of the most important vitamin E derivatives,that were used as antioxidants. Adsorbents like kaolin, magnesium carbonate, and microcrystalline cellulose were used successfully to incorporate oily alpha-tocopherol acetate into an acceptable powder dosage form. The results revealed that microcrystalline cellulose as an adsorbents gave the best results with 50% loading capacity at time, 8 minutes before and after incubation period (3 months at 30C°), while kaolin and magnesium carbonate have been shown a significant difference before and after incubation. Addition of 1% w/w magnesium carbonate to the kaolin enhanced the loading capacity by decreasing the time of adsorption from 20 to 6 minutes and 47
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Increasing the power conversion efficiency (PCE) of silicon solar cells by improving their junction properties or minimizing light reflection losses remains a major challenge. Extensive studies were carried out in order to develop an effective antireflection coating for monocrystalline solar cells. Here we report on the preparation of a nanostructured cerium oxide thin film by pulsed laser deposition (PLD) as an antireflection coating for silicon solar cell. The structural, optical, and electrical properties of a cerium oxide nanostructure film are investigated as a function of the number of laser pulses. The X-ray diffraction results reveal that the deposited cerium oxide films are crystalline in nature and have a cubic fluorite. The field
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