The aim of present investigation was to evaluate the efficacy of the full thickness flap with internal mattress, suture in eliminating deep periodontal pockets in maxillary anterior region, to gain attachment and to preserve the height of the papilla prior to the periodontal surgery. Ten patients suffering from adult periodontitis in maxillary anterior region with minimum of two pockets;≥6mm were Participated in this study. Prior to the above surgery the first chase of therapy was performed the following clinical parameters1- Pocket depth2- Attachment level3- Height of papilla were measured one dayBefore the surgery and three months after the surgery. The total of 34 Pocket ≥ 6 mm was treated and the height of 224 papilla was measured. The mean difference between first two parameters. (Post surgical compare to pre surgical...) were 3.235 and 1.93 mm respectively which the differences were significant. Also the mean difference for the 3rd parameter was 1.305 mm which despite of being significant was acceptable (the differences between 3rd parameters less or closer to zero to be more acceptable. This technique is useful for eliminating pockets in maxillary anterior region.

The present work investigates the effect of the elliptical three-dimensional (3D) cracks on a Pipe with thickness transition, considering internal pressure. Level sets were defined using the extended finite element method (XFEM), the stress intensity factors (SIFs) of 3D cracks were investigated and compared between straight Pipes and Pipes with thickness transition. The results show that the XFEM is an effective tool for modeling crack in Pipes. A pressurized Pipe with thickness transition is more sensitive to the feature compared to the straight Pipe. Parameters of the transition zone have an influence on stress intensity factors. Quantification of the SIFs associated with cracks in the transition zone of Pipes with thicknesses is performed.

An important issue in power generation and petrochemical industries is the monitoring of Pipe wall thickness and corrosion/erosion rate. The Pipes are usually subject to erosive and/or corrosive environments and any failure could be catastrophic. While periodic manual ultrasonic thickness measurement is the common practice in many industries, in certain cases, where higher accuracies are required, continuous monitoring systems are required. This paper introduces a measurement algorithm that can accurately measure the Pipe wall thickness and estimate the Pipe-wall thinning rate. The algorithm incorporates a model-based estimation technique for estimating the Pipe wall thickness and thinning rate. It is an on-line non-intrusive ultrasonic thickness measurement tool for quick and accurate estimation of the erosion/corrosion rate and remaining Pipe-wall thickness. The technique is applied to data measured from a Pipe carrying high temperature liquid. The results show that the system can measure thinning rates as low as 10 µm/year within 5 days of data collection.

The elastic-plastic behavior of the material is considered to analyze the effect of an external circumferential crack on a Pipe with thickness transition and double slopes. Using the extended finite element method (XFEM), the J-integral of 3D cracks were investigated and compared between straight Pipes and Pipes with thickness transition and different slopes. Considering internal pressure, this work highlighted the investigation of a 3D crack problem in a thickness transition Pipe with a double slope, In the extended finite element method (XFEM), the level sets and the enrichment zone were defined. A crack is easily modeled by enrichment functions. The comparison between the values of the Jintegral showed that the Pipe containing thickness transition with double slopes is more sensitive to the considered cracks, more precisely, the parameters of the first thickness transition have more influence on the variation of J-integral than the parameters of the second thickness transition. The decreasing of the angle of the slopes and the increase of the ratio of the thicknesses is one effective method of reducing the J-integral.

The Pipes conveying fluid are capable of displaying complex dynamical behaviors. In this paper, the dynamic behavior of a simply supported fluid-conveying Pipe made of functionally graded material in thickness direction, is analysed. The Young Modulus are assumed to be graded along the thickness direction according to a simple power law and equations of motion of the Euler– Bernoulli beam are derived. The partial differential equation is discretized to ordinary differential equations by the Galerkin method. The natural frequencies are obtained for different dimensionless parameters and compared with a homogenious Pipe conveying fluid, and the effect of gradually changed material has been studied. Dimensionless critical flow velocities which couse instability are obtained for particular mass parameter and different distribution of Young Modulus. The results show that by increasing Young Modulus from inner to outer surface of Pipe, the natural frequencies of system increase and instability is occurred in higher critical velocities.

The behavior of the buried Pipes under the fault displacement is a complex issue. In the past earthquakes, fault displacement of 2.1, 3 and 4 meters have been reported. A review on the literature shows that understanding failure modes of buried Pipelines under big fault displacement is considered as a challenge. In this paper, the objective is to investigate the influence of the thickness parameters of the Pipe on Pipe behavior at Pipe intersection and fault. The behavior of the Pipe is studied focusing on fault displacements greater than 1 meter. Using finite element ABAQUS software, the simulation was performed through dynamic analysis regarding to Pipe-soil interaction. Pipe and soil Dimensions and material properties of the soil and Pipe are fixed in all analyzed samples and, the fault displacement (0.2 to 3 meters) and the Pipe thickness (from 8.2 to 20 mm) are variable parameters of this article. An analysis has been conducted for the two variables (fault displacement and the thickness of the Pipe). Maximum axial strain values and Pipe deformation modes under fault displacement are discussed. Likewise, the influence of Pipe thickness and the amount of fault displacement on the value of strain of the Pipe wall is indicated in numerical analysis in the result. In the displacement of less than 1 meter, the Pipes are like the letter S and local buckling occurs in the Pipeline. In the displacement of 1.5 meters and more, they are like the letter Z, and Pipe deformation and wrinkling occur in the Pipeline. In the displacement of more than 1.5 meters, distortion, and wrinkling Pipe is deformed. In the displacement of more than 1 m, the strain decreases with increasing Pipe thickness. Through the change of the Pipe thickness, the Pipe failure mode changes.

Background and Aim: The accuracy of linear measurements in CBCT images is one of the critical parameters in treatment planning. Slice thickness and exposure parameters seem to affect the accuracy of linear measurements. In this study, we investigated the impact of the above factors on the accuracy of linear measurements in CBCT. Materials and Methods: For the in vitro experiment, three dry human maxilla and mandibles were selected and the roots of their teeth were used as markers at the points of the anterior, premolars, and molars on both sides and placed in the desired locations. A digital caliper was used to measure its height and width prior to placement as the Gold Standard. For each location, the images were examined in slice thickness with dimensions of 0. 5, 1, 2 and 3 mm and a kVp = 84 and a kVp = 90 and the results were then compared with Gold standard. The data were analyzed using the ANOVA test. Results: The results of this study showed that the effect of slice thickness, kvp, location and type of jaw were not significant for measuring the length of the marker (p>0. 05) but about measuring the width of marker, in maxillary anterior and molar area and in mandibular premolar and molar area slice thickness was significant (p <0. 05) and the effect of kVp was not significant (p >0. 05). Similarly, the effects of slice thickness and kVp were also significant in the maxillary premolar area (p <0. 05), whereas in the anterior mandibular area, the effect was not significant (p >0. 05). Conclusion: The accuracy of CBCT in measurement is very high although, for CBCT measurements to be as accurate as possible, it is desirable to use thinner slice thicknesses and higher voltages.

In this paper, the effect of ductile damage on the behavior of a dented Pipe subjected to internal pressure is investigated by experimental and numerical methods. In the numerical investigation, the plastic behavior of Pipes under indentation is studied using continuum damage mechanics theory and the elastic-plastic finite element analysis. Finite element calculations are carried out using the damage plasticity model proposed by Xue and Wierzbicki (X-W).The proposed damage plasticity model incorporates effects of four parameters that play an important role in predicting the fracture initiation, namely the damage rule, the softening effect, the hydrostatic pressure and the Lode angle. The target dent depth is considered an indication of the load bearing capacity of the Pipe under indentation process by a rigid spherical indenter. To validate numerical calculations, a series of experimental tests are conducted on the API XB steel Pipe with atmospheric pressure. After verification, numerical calculations for different ranges of internal pressures, wall thickness and indenter diameter with and without damage effect are carried out for aluminum 2024-T351 Pipe and results are compared. It is shown that damage plays an important role on the load bearing capacity of an indented Pipe. Results of the present study confirm the credibility of the proposed model in predicting the ductile fracture under multi-axial state of stress loadings.

In this research, in order to investigate the effect of the piezoelectric patch which is used as a sensor or actuator in rotating flexible structures such as a helicopter blade, the free vibrations of the rotating rectangular sheet with and without the piezoelectric patch have been presented. First-order shear deformation theory is considered for plate displacement and piezoelectric field. Considering the effect of Coriolis acceleration, centrifugal acceleration and centrifugal in-plane forces, the equations of motion are derived from Hamilton's principle and the electromechanical couple equation is obtained from Maxwell's equation. For piezoelectric, two electrical conditions, open circuit and closed circuit, which are used in sensors and actuators, respectively, have been considered. The equations are discretized with the help of the numerical method of generalized differential squares and the matrices of inertia mass, eccentricity, Coriolis and stiffness matrix are obtained. Natural frequency values for beam and rotating plate have been compared in Abaqus software. Also, the values obtained from the numerical solution in MATLAB have been verified with articles and ABAQUS, which have high accuracy. The effect of parameters such as hub radius, rotation speed, sheet thickness, aspect ratio, piezoelectric patch thickness and applied voltage on the natural frequency of the system has also been investigated.