In this paper, a polymer-based composite material was prepared by hand Lay-up method consisting of epoxy resin as a base material reinforced by magnesium oxide powder once and silicon dioxide powder again and with different weight ratios (3, 6, 9 and 12) wt %. The three-point bending test was performed in normal conditions and after immersion in sulfuric acid. The results showed that the bending value decreased with the increase of the weighted ratio of the reinforcement material (MgO, SiO2). The Bending of samples reinforced by SiO2 was found to be less than the bending of samples reinforced by particles (MgO). For example, the bending of the SiO2 sample (0.32 mm) at the weighted ratio (3%) and for the MgO (0.18mm) sample at the weight ratio were the same weighted load (100 g). It was found that the bending values of all samples exceeded the value after immersion in sulfuric acid. For example, the percentage of weight (6%) at the load level (500 g) was changed from 1.16 mm in normal conditions to 1.48mm for the same weight ratio after immersion. In sulfuric acid diluted with 0.3N for 10 days at the same applied load.
Hydrogels are hydrophilic biocompatible polymers that can be used as a drug delivery material in different medical branches, including vital pulp therapy. The aim of this study is to characterize the physical and biological properties of the newly developed formula as a candidate direct pulp-capping material. The hydrogel composite was prepared from natural and synthetic origins (polyvinyl alcohol (PVA), hyaluronic acid (HA), and sodium alginate (SA)) with the incorporation of bioactive Moringa. Different formulas of hydrogel containing different concentrations were evaluated for physicochemical (FTIR, XRD, SEM, degradation, and swelling), mechanical (viscosity, folding endurance, film thickness), and biological (antioxidant, antibacterial,
... Show MoreThe compressive residual stresses generated by shot peening, is increased in a direct proportional way with shot peening time (SPT). For each metal, there is an optimum shot peening time (O.S.T) which gives the optimum fatigue life. This paper experimentally studied to optimize shot peening time of aluminium alloy 6061-T651 as well as using of and analysis of variance (ANOVA).
Two types of fatigue test specimens’ configuration were used, one without notch (smooth) and the other with a notch radius (1,25mm), each type was shot peened at different time. The (O.S.T) was experimentally estimated to be 8 minutes reaching the surface stresses at maximum peak of -184.94 MPa.
A response surface methodology (RSM) is presen
... Show MoreDicephalus parapagus twinning (DPT) is the rarest conjoined twinning entity of all conjoined twins. The presence of DPT is always associated with mortality before or after delivery. Antenatal diagnosis is crucial for planning labor, assembling a team, and providing counseling. Case presentation: A 23-year-old patient (G2P1A0) at 21 weeks of pregnancy attended the ultrasound clinic for routine care. A monoamniotic-monochorionic pregnancy was observed; the twin fetuses had two heads but one body, which corresponded to dicephalus parapagus twinning. A detailed ultrasound and fetal echocardiography reveal one heart without congenital anomalies. The liver, kidneys, and bladder appeared to be normally developed. Fetal MRI and karyotyping wer
... Show MoreIn this study, a new class of polymeric nanocomposites was synthesized and characterized. One mole of dimethyl adipate and two moles of thiosemicarbazide in ethanol first reacted to form the compound [C1]. Compound [C1] then reacted with sodium hydroxide to produce compounds [C2]. Hydrazine hydrate reacted with compound [C2] to generate compound [C3]. Compound [C4] was synthesized from compound [C3] and maleic anhydride. A polymer [C5] is formed by the reaction of the compound [C4] with ammonium persulfate as an initiator. This polymer was then combined with nano: ZnNPs, AgNPs, SiNPs, or IONPs using a hotplate stirrer for 3 hours to produce nanocomposites [C6-C9]. FTIR, 1H-NMR, and Field Emission Scanning Electron Microscope (FESEM) were
... Show MoreThe effect of molecules intersystem crossing (Kisc) on characteristics
(energy and duration) of a Passive Q- switched Laser Pulse has been
studied by mathematical description (rate equations model) for
temporal performance of which was used as a saturable absorber
material (passive switch) with laser. The study shows that the energy
and duration pulse are decreasing while the molecules intersystem
crossing into saturable absorber energy levels is increasing.
Aim of the study: Using surface roughness and tensile bond strength tests, the objective of this investigation was to ascertain the impact of laser surface modification on the binding strength of injectable thermoplastic acrylic denture base material to acrylic-based soft-liner material. Materials and methods: Acrylic base soft liner material was bonded to injectable thermoplastic acrylic resin (Deflex). Forty specimens were created (20 disc, 20 dumbbells) 10 of each specimen type as control specimens, and 10 were treated with nano pulse Nd: YAG laser. The data were analyzed using the Kruskal-Wallis test and unpaired t-test (a=.05) and the roughness test was performed utilizing a double column universal test machine. Results: Compar
... Show MoreCr2O3 thin films have been prepared by spray pyrolysis on a glass substrate. Absorbance and transmittance spectra were recorded in the wavelength range (300-900) nm before and after annealing. The effects of annealing temperature on absorption coefficient, refractive index, extinction coefficient, real and imaginary parts of dielectric constant and optical conductivity were expected. It was found that all these parameters increase as the annealing temperature increased to 550°C.