Preferred Language
Articles
/
QBaUVYcBVTCNdQwCGUbS
Effects of Artificial Aging on Some Properties of Room-Temperature-Vulcanized Maxillofacial Silicone Elastomer Modified by Yttrium Oxide Nanoparticles
...Show More Authors

Abstract Background: The daily usage of maxillofacial prostheses causes them to mechanically deteriorate with time. This study was aimed to evaluate the reinforcement of VST50F maxillofacial silicone by using yttrium oxide (Y2O3) nanoparticles (NPs) to resist aging and mechanical deterioration. Materials and Method: Y2O3 NPs (30–45nm) were loaded into VST50F maxillofacial silicone in two weight percentages (1 and 1.5 wt%), which were predetermined in a pilot study as the best rates for improving tear strength with minimum increase in hardness values. A total of 120 specimens were prepared and divided into the control and experimental groups (with 1 and 1.5 wt% Y2O3 addition). Each group included 40 specimens, 10 specimens for each parameter tested (i.e., tear strength, surface roughness, hardness, tensile strength and elongation percentage). Specimens were artificially aged in a weathering chamber for 150 h and then tested. Data were analyzed by ANOVA and Tukey’s honestly significant difference (HSD). Statistical significance was set to P ≤ 0.05. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were also conducted. Results and Discussion: SEM results showed that Y2O3 NPs were distributed well within the silicon matrix. FTIR results indicated that the NPs were physically dispersed within VST50F silicone without chemical interaction. After 150 h of accelerated artificial aging, adding Y2O3 NPs significantly increased the tear strength, hardness, surface roughness, and elongation percentage. Tensile strength increased non significantly. Conclusion: Adding Y2O3 NPs as fillers improved the mechanical properties of artificially aged maxillofacial silicone elastomer. Keywords: maxillofacial silicone, Y2O3, nanoparticles, fillers, artificial aging.

Scopus Crossref
View Publication
Publication Date
Wed Mar 01 2023
Journal Name
Journal Of Engineering
Effect of a Parked Car Orientation on a Temperature Distribution and Cooling Load Calculation: Experimental Study
...Show More Authors

When a vehicle is left parked in the sun for an extended period, the gathered heat causes damage to several interiors within the cabin and causes discomfort for people and animals left inside the car. In the present work, the effect of the orientation of a parked white minibus on temperature distribution and cooling load calculation is studied experimentally in an open environment. Two different cases were studied facing south and facing east. For several hours, the temperature inside the car cabin had been monitored and measured at five separate locations. The cooling load calculations are carried out based on the experimental measurements. The results show that the overheating of parked cars always happens as a result

... Show More
View Publication Preview PDF
Scopus (3)
Crossref (2)
Scopus Crossref
Publication Date
Sun Mar 30 2014
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Structure Rheology of Polyethylene Oxide Solution
...Show More Authors

Intrinsic viscosities have been studied for polyethylene oxide in water which has wide industrial applications. The polyethylene oxide samples had two different structures, the first one was linear and covers a wide range of molecular weight of 1, 3, 10, 20, 35, 99, 370, 1100, 4600, and 8000 kg/mol and the second one was branched and had molecular weights of 0.55 and 40 kg/mol.
Intrinsic viscosities and Huggins constants have been determined for all types and molecular weights mentioned above at 25ºC using a capillary viscometer. The values of Mark-Houwink parameters (K and a) were equal to 0.0068 ml/g and 0.67 respectively, and have not been published for this range of molecular weight in as yet.

View Publication Preview PDF
Publication Date
Thu Jun 15 2023
Journal Name
Journal Of Baghdad College Of Dentistry
The Effect of titanium dioxide nanoparticles on the activity of salivary peroxidase in periodontitis patients
...Show More Authors

Background:The technology of nanoparticles has been expanded to many aspects of modern life. Titanium dioxide nanoparticles were of many nanomaterials utilized in biomedical applications. The interactions between nanoparticles and proteins are believed to be the base for the biological effect of the nanoparticles. The oxidation reaction of many substances is catalyzed by oxidizing enzymes called peroxidases. The activity of salivary peroxidase is elevated with periodontal diseases. the aim ofthis study is to examine the action of titanium dioxide nanoparticles on salivary peroxidase activity.Material and method75 participants were enrolled in this study—Periodontitis group with 44 participants and the non-periodontitis group with 31 pa

... Show More
View Publication Preview PDF
Scopus (5)
Crossref (2)
Scopus Crossref
Publication Date
Fri Jul 01 2022
Journal Name
Health Science Reports
Immunohistochemical expression of angiotensin‐converting enzyme 2 in superficial and deep maxillofacial tissues: A cross‐sectional study
...Show More Authors
Abstract<sec><title>Background and Aims

The involvement of maxillofacial tissues in SARS‐CoV‐2 infections ranges from mild dysgeusia to life‐threatening tissue necrosis, as seen in SARS‐CoV‐2‐associated mucormycosis. Angiotensin‐converting enzyme 2 (ACE2) which functions as a receptor for SARS‐CoV‐2 was reported in the epithelial surfaces of the oral and nasal cavities; however, a complete understanding of the expression patterns in deep oral and maxillofacial tissues is still lacking.

Methods

The immunohistochemical expression of ACE2 was analyzed in 95 specimens from maxillofacial tissues and 10 specimens o

... Show More
View Publication
Scopus (4)
Crossref (5)
Scopus Clarivate Crossref
Publication Date
Wed Dec 13 2017
Journal Name
Al-khwarizmi Engineering Journal
Energy and Exergy Analysis on Modified Closed Wet Cooling Tower in Iraq
...Show More Authors

The present study involves experimental analysis of the modified Closed Wet Cooling Tower (CWCT) based on first and second law of thermodynamics, to gain a deeper knowledge in this important field of engineering in Iraq. For this purpose, a prototype of CWCT optimized by added packing under a heat exchanger was designed, manufactured and tested for cooling capacity of 9 kW. Experiments are conducted to explore the effects of various operational and conformational parameters on the towers thermal performance. In the test section, spray water temperature and both dry bulb temperature and relative humidity of air measured at intermediate points of the heat exchanger and packing. Exergy of water and air were calculated by applying the exergy

... Show More
View Publication Preview PDF
Publication Date
Mon Oct 05 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Assessment of some mechanical properties of Imprelon® and Duran® thermoplastic Biostar machine sheets in comparison with some types of acrylic resins
...Show More Authors

Background: Imprelon® Biostar foils are new alternative tray material that has become increasingly popular because oftheir several advantages. Also, (Duran®) is another type of Biostar foils which is used in splint therapy. This study assessed some mechanical properties of these two types Biostar sheets in comparison with some types of acrylic resins used for construction of trays and splints. Materials and Methods: A total of 150 specimens were prepared, 30 specimens for each test, 10 for each group material in order to assess some mechanical properties of the Imprelon® Biostar foil (dimension stability, surface roughness and shear bond strength of Imprelon® materialto zinc oxide impression material) and compare them to that of the oth

... Show More
View Publication Preview PDF
Publication Date
Mon Feb 01 2016
Journal Name
Journal Of Engineering
Fatigue Behavior of Modified Asphalt Concrete Pavement
...Show More Authors

Fatigue cracking is the most common distress in road pavement. It is mainly due to the increase in the number of load repetition of vehicles, particularly those with high axle loads, and to the environmental conditions. In this study, four-point bending beam fatigue testing has been used for control and modified mixture under various micro strain levels of (250 μƐ, 400 μƐ, and 750 μƐ) and 5HZ. The main objective of the study is to provide a comparative evaluation of pavement resistance to the phenomenon of fatigue cracking between modified asphalt concrete and conventional asphalt concrete mixes (under the influence of three percentage of Silica fumes 1%, 2%, 3% by the weight of asphalt content), and (chan

... Show More
View Publication Preview PDF
Publication Date
Sun Dec 30 2001
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Isolation Behavior of Metal Modified Novolac Resin
...Show More Authors

View Publication Preview PDF
Publication Date
Tue Sep 01 2009
Journal Name
Al-nahrain Journal Of Science
Colorimetric assay of aspirin using modified method
...Show More Authors

In this research, we did this qualitative and quantitative study in order to improve the assay of aspirin colorimetrically using visible spectrophotometer. This method depends on aqueous hydrolysis of aspirin and then treating it with the ferric chloride acidic solution to give violet colored complex with salicylic acid, as a result of aspirin hydrolysis, which has a maximum absorption at 530nm. This procedure was applied to determine the purity of aspirin powder and tablet. The results were approximately comparative so that the linearity was observed in the high value of both correlation coefficient (R= 0.998) and Determination Coefficient or Linearity (R2= 0.996) while the molar absorpitivity was 1.3× 103 mole

Publication Date
Tue Jan 17 2012
Journal Name
Journal Of Electron Devices
INVESTIGATION OF OPTICAL PROPERTIES OF THE PbS/CdS THIN FILMS BY THERMAL EVAPORATION
...Show More Authors

In this work, we have investigated optical properties of the thermally evaporation PbS/CdS thin films. The optical constant such as (refractive index n, dielectric constant εi,r and Extinction coefficient κ) of the deposition films were obtained from the analysis of the experimental recorded transmittance spectral data. The optical band gap of PbS/CdS films is calculate from (αhυ)1/2 vs. photon energy curve.