The building of domes in Persia dates back to the third millennium B.C. Since then, the architecture of Persia has produced many types of dome structures using traditional methods to make the best forms of domical shapes. The earliest Iranian dome that still stands was built in Firuzabad, South-west Iran, about 1, 800 years ago. Round, ovoid and parabolic domes were built until the seventh century A.D. Low saucer-like domes were constructed later. Double-shell domes appeared in the eleventh century A.D. In the twelfth century A.D., round and smooth, or octagonal domes, rising to a sharp peak, crowned circular or octagonal structures. High domes were placed on tall drums in the fourteenth century A.D. Bulbous domes became current later. The onion-shaped domes were built on shrines in the eighteenth century A.D. The brick masonry dome is an important element of Persian historical architecture. The identification of its structural behavior and the study of the effect the dome shape on its behavior is an important issue. Domes in this study have the most common shapes in Persian architecture and no study has been done about their optimum shape.In this research, shape optimisation of Persian historical brick masonry domes with different geometrical shapes under uniform pressure has been studied and then the Failure Load under concentric Loading and buckling Load under uniform pressure have been determined for optimal domes. The studied domes have semi-circular, pointed and four-centred cross-sections. Pointed and four-centred domes have three types of drop, ordinary and raised shapes. Seven types of domes with spans of 12 m, 15 m and 18 m have been analysed by the finite element method using the ANSYS code. Material behaviour has been assumed non-linear and the Willam-Warnke Failure criterion and, in some cases, the maximum principal stress theory has been used. The parameter used for optimisation is the minimum ratio of apex thickness to base thickness (K) for which the Failure Load to weight ratio is a maximum. For uniform pressure, K=0.2 is the optimum ratio for semi-circular domes. For pointed domes the optimum ratio is K=0.3, except for the ordinary pointed dome with a span of 18 m for which the optimum ratio is K=0.08. The optimum value is K=0.3 for ordinary fourcentred dome with a span of 12 m and raised four-centred dome with a span of 15 m, it is K=0.54 for raised four-centred dome with a span of 12 m, and it is K=0.144 for other types of four-centred domes. The Failure Load of domes with optimum shapes under concentrated Loads is more than that of non-optimum shapes. Buckling Load of optimal domes is much more than Failure Load under uniform pressure. Buckling Load increases by decreasing the span. The maximum and minimum values of buckling Load belong to pointed and semi-circular domes, respectively.

In recent years, the definition and analysis of inverse hyperelastic problems due to the wide use of these materials in various industries and also in manufacturing of artificial tissues of the body, has received more attention than before. In mechanical analysis of hyperelastic materials, both material behavior and material deformation are considered nonlinear. In this article, an inverse problem related to the Failure of hyperelastic bodies is defined and two different methods are proposed to solve it. The inverse analysis of hyperelastic bodies that have failed, can be useful to prevent the recurrence of Failure in these materials. In the inverse problem, it is assumed that a two-dimensional hyperelastic solid is failed and the place of its Failure is known. The distribution of the Load (boundary conditions) in a part of the boundary is considered unknown and is calculated by solving the inverse problem. By defining an appropriate objective function, the defined inverse problem is converted to an unconstrained optimization problem. To solve the optimization problem, a zero-order method based on the equal interval search method and a first-order method based on the steepest descent method are used. To make the problem more practical, the inverse problem input data, which are the location of Failure and the critical equivalent strain, are used with some error. Finally, considering the location of the Failure and the critical equivalent strain, the Load causing Failure is identified. It can be seen that the performance of the first-order method is better than the zero-order method.

This paper explores the use of artificial neural networks in predicting the Failure Load of castellated beams. 47 experimental data collected from the literature cover the simply supported beams with various modes of Failure, under the action of either central single Load, uniformly distributed Load or two-point Loads acting symmetrically with respect to the center line of the span. The data are arranged in a format such that 8 input parameters cover the geometrical and Loading properties of castellated beams and the corresponding output is the ultimate Failure Load. A back-propagation artificial neural network is developed using Neuro-shell predictor software, and used to predict the ultimate Load capacity of castellated beams. The main benefit in using neural network approach is that the network is built directly from the experimental or theoretical data using the self-organizing capabilities of the neural network. Results are compared with available methods in the literature such the Blodgett's Method and the BS Code. It is found that the average ratio of actual to predict Failure Loads of castellated was 0.99 for neural network, 2.2 for Blodgett's Method and 1.33 for BS Code. It is clear that neural network provides an efficient alternative method in predicting the Failure Load of castellated beams.      

Watermelon is handled and stored in bulk package as some other fruits and vegetables are. Package height must be so appropriately selected that bottom fruit layers will receive no damage or Failure. This research was performed to determine and compare the mechanical properties of two varieties in three sizes of watermelon under static Load conditions to obtain parameters used in transportation as well as in storage. A statistical factorial experiment in the form of a completely randomized design (2×3×2) of five replications was employed to determine the mechanical properties of watermelon in whole watermelon. Such factors as Failure force, Failure deformation and fruit rind thickness were among those determined. It is found that the Failure force was affected by the direction in which it was exerted. Failure force in the longitudinal direction was less than that in the transverse direction while variation in size of the fruit did not significantly affect either Failure force or Failure deformation. Results also indicated that Failure force and Failure deformation were significantly affected by variety. Mean Failure forces for Charleston Gray and Crimson Sweet varieties were 1.1 and 1.8 kN, respectively. Investigation of rind thickness in different varieties and sizes of watermelon demonstrated that five millimeter increase in rind thickness can increase Failure force up to 70%.

Investigation of behaviour of non-persistent joint is important in rock structure stability. This leads to improvement in rock engineering project design. Rock bridges in non-persistent joint increase shear strength of Failure surface. For investigation of shear behaviour of rock bridges, 24 gypsum samples with dimension of 10 cm × 10 cm × 5 cm were prepared. The joint lengths in various samples are different but in the one sample the joint length are similar. Joint lengths change from 1 cm to 4 cm. in each joint length, joint angularity was 0, 15, 30, 45, 60, 75 degrees. These samples were under uniaxial compression test. The results show that Failure pattern was affected by joint length, joint angularity and rock bridge length while Failure Load was controlled by Failure pattern. Concurrent with experimental test, numerical simulation was performed using PFC2D software. The joint lengths in numerical model change from 1cm to 4 cm with increment of 1cm. In each joint length, the joint angularity is 0° and 45° . Failure pattern in numerical model was similar to experimental sample while Failure Load in numerical model was more than experimental outputs.

Background and Aim: It is believed that a period of healing, approximately 3-4 months for mandible and 4-6 months for maxilla, are required to ensure osseointegration. Recently, a new method called Immediate Loading of implants have been proposed. This method provides improved stability of the implant by the immediate support of an iterim prosthesis. The aim of this study was to evaluate the success rate of the Immediate Loading single OPILS dental implants.Materials and Methods: Thirty-nine patients, including 26 females and 13 males, at the minimum age of 18 and maximum age of 54 years old, received 48 OPILS dental implants. In this prospective study, all samples were non-smoking, without any systemic disease or psychological problem. In all cases, and acrylic prefabricated crown was placed immediately after implant surgery. The definitive metal-ceramic crown was placed 2.5 months later in mandible and 5.5 months later in maxillae. Lack of pain, pus, implant immobility and less than 1mm bone loss were criteria of success.Results: The oral hygiene of females were better than males, 26 women had plaque index (0) and 11 of them had plaque index (1) where as out of 13 male subjects, 4 had plaque index (0), 6 had plaque index (2) and (3) had plaque index (3). The mean vertical bone loss, on mesial and distal parts, were less than 1mm, with the min. of 0 and max. of 0.4mm and the average of 0.2mm. All implants pass the defined criteria of success.Conclusion: On the basis of this short-term study, in single tooth cases, OPILS implants of Neo-Dent system can be Loaded immediately.