Objectives: This study aims to assess and compare the micro-shear bond strength (μSBS) of a novel resin-modified glass-ionomer luting cement functionalized with a methacrylate co-monomer containing a phosphoric acid group, 30 wt% 2-(methacryloxy) ethyl phosphate (2-MEP), with different substrates (dentin, enamel, zirconia, and base metal alloy). This assessment is conducted in comparison with conventional resin-modified glass ionomer cement and self-adhesive resin cement. Materials and methods: In this in vitro study, ninety-six specimens were prepared and categorized into four groups: enamel (A), dentin (B), zirconia (C), and base metal alloys (D). Enamel (E) and dentin (D) specimens were obtained from 30 human maxillary first premolars extracted during orthodontic treatment. For zirconia and metal alloys, 48 disks were manufactured using IPS e.max ZirCAD through dry milling and Co–Cr powder alloy by selective laser milling. Each group was further subdivided into three subgroups (n = 8) according to the luting cement used: (1) Fuji PLUS resin-modified glass ionomer luting cement (FP) as a control cement, (2) modified control cement (eRMGIC), and (3) RelyX U 200 (RU 200) self-adhesive resin cement. The two-way analysis of variance and Tukey’s HSD were used to assess the data obtained from measuring the μSBS of the samples. Results: The results of this study showed that the mean μSBS values of eRMGIC were statistically higher compared to FP in all tested groups (p < 0.001). The mean μSBS results of eRMGIC were non-significantly different from those recorded by RU 200 for all substrates except for the dentin substrate, where the RU200 cement produced significantly higher strength (p < 0.001). The failure modes were limited to a combination of mixed and adhesive failures without pure cohesive failure. Significance: The functionalization of FP with an organophosphorus co-monomer (2-MEP) directly affects the adhesion performance of the functionalized cement, which may be utilized to develop a new type of acid-base cement. It exhibited a performance comparable to that of resin-based cement and should serve well under different clinical conditions.
This paper presents a modified training method for Recurrent Neural Networks. This method depends on the Non linear Auto Regressive (NARX) model with Modified Wavelet Function as activation function (MSLOG) in the hidden layer. The modified model is known as Modified Recurrent Neural (MRN). It is used for identification Forward dynamics of four Degrees of Freedom (4-DOF) Selective Compliance Assembly Robot Arm (SCARA) manipulator robot. This model is also used in the design of Direct Inverse Control (DIC). This method is compared with Recurrent Neural Networks that used Sigmoid activation function (RS) in the hidden layer and Recurrent Neural Networks with Wavelet activation function (RW). Simulation results shows that the MRN model is bett
... Show MoreThe present paper concerns with the problem of estimating the reliability system in the stress – strength model under the consideration non identical and independent of stress and strength and follows Lomax Distribution. Various shrinkage estimation methods were employed in this context depend on Maximum likelihood, Moment Method and shrinkage weight factors based on Monte Carlo Simulation. Comparisons among the suggested estimation methods have been made using the mean absolute percentage error criteria depend on MATLAB program.
This paper demonstrates an experimental and numerical study on the behavior of reinforced concrete (RC) columns with longitudinal steel embedded tubes positioned at the center of the column cross-section. A total of 12 pin-ended square sectional columns of 150 × 150 mm having a total height of 1400 mm were investigated. The considered variables were the steel tube diameters of 29, 58, and 76 mm and the load eccentricity (0, 50, and 150) mm. Accordingly, these columns were divided into three groups (four columns in each group) depending on the load eccentricity (e) to column depth (h) ratio (e/h = 0, 1/3, and 1). For each group, one column was solid (reference), and the other three columns contained steel tubes with hollow rat
... Show MoreIn this paper, a methodology is presented for determining the stress and strain in structural concrete sections, also, for estimating the ultimate combination of axial forces and bending moments that produce failure. The structural concrete member may have a cross-section with an arbitrary configuration, the concrete region may consist of a set of subregions having different characteristics (i.e., different grades of concretes, or initially identical, but working with different stress-strain diagrams due to the effect of indirect reinforcement or the effect of confinement, etc.). This methodology is considering the tensile strain softening and tension stiffening of concrete in additio
This study uses an Artificial Neural Network (ANN) to examine the constitutive relationships of the Glass Fiber Reinforced Polymer (GFRP) residual tensile strength at elevated temperatures. The objective is to develop an effective model and establish fire performance criteria for concrete structures in fire scenarios. Multilayer networks that employ reactive error distribution approaches can determine the residual tensile strength of GFRP using six input parameters, in contrast to previous mathematical models that utilized one or two inputs while disregarding the others. Multilayered networks employing reactive error distribution technology assign weights to each variable influencing the residual tensile strength of GFRP. Temperatur
... Show MoreAbstractThe objective of the present study was measured of several oxidative stresses and liver function parameters in workers occupationally exposed to cement dust in Kufa Cement Factory, in order to test the hypothesis that cement dust exposure may perturb these parameters. Assessment of oxidative stress and liver function parameters were performed in 63 workers occupationally, in different departments of Kufa Cement Factory, exposed to cement dust (range of the exposure time was 5-38 years) and 36 matched unexposed controls. The study results illustrated an increasing in the oxidative stress parameters, moreover; liver function parameters showed abnormal results in the exposed workers compared to the unexposed. An increase in theses para
... Show MoreObjectives Dental implant is a revolution in dentistry; some shortages are still a focus of research. This study use long duration of radiofrequency (RF)–magnetron sputtering to coat titanium (Ti) implant with hydroxyapatite (HA) to obtain a uniform, strongly adhered in a few micrometers in thickness. Materials and Methods Two types of substrates, discs and root form cylinders were prepared using a grade 1 commercially pure (CP) Ti rod. A RF–magnetron sputtering device was used to coat specimens with HA. Magnetron sputtering was set at 150 W for 22 hours at 100°C under continuous argon gas flow and substrate rotation at 10 rpm. Coat properties were evaluated via field emission scanning electron microscopy (FESEM), scanning electro
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