In this paper, an analytical solution describing the deflection of a cracked beam repaired with piezoelectric patch is introduced. The solution is derived using perturbation method. A novel analytical model to calculate the proper dimensions of piezoelectric patches used to repair cracked beams is also introduced. This model shows that the thickness of the piezoelectric patch depends mainly on the thickness of the cracked beam, the electro-mechanical properties of the patch material, the applied load and the crack location. Furthermore, the model shows that the length of the piezoelectric patches depends on the thickness of the patch as well as it depends on the length of the cracked beam and the crack depth. The additional flexibility of the beam caused by crack is modeled depending on a dimensionless parameter identified from finite elements method. Different piezoelectric patches were designed and investigated using analytical and finite elements models. The results show that increasing the patch thickness enhances the beam resistance to crack and load effects, while increasing the length of the piezoelectric patch reduces the magnitude of the voltage required to repair the cracked beam.
This paper presents the results of experimental investigations to predict the bearing capacity of square footing on geogrid-reinforced loose sand by performing model tests. The effects of several parameters were studied in order to study the general behavior of improving the soil by using the geogrid. These parameters include the eccentricity value, depth of first layer of reinforcement, and vertical spacing of reinforcement layers. The results of the experimental work indicated that there was an optimum reinforcement embedment depth at which the bearing capacity was the highest when single-layer reinforcement was used. The increase of (z/B) (vertical spacing of reinforcement layer/width of footing) above 1.5 has no effect on the re
... Show MoreConcrete is the main construction material of many structures. Exposing to loads creates cracks in concrete, which reduce the performance and durability. The decrease of concrete cracks becomes a necessity demand to ensure more durability and structural integrity of the concrete structure. Autogenous healing concrete is a kind of new smart concretes, which has the ability to reclose its cracks by means of itself. Concrete self-healing is a type of free repairs processes, which is reduce direct and indirect cost of maintenance and repairing. This work targets to inspect the mechanical properties of concrete after using two combinations of two materials (20 kg/m3 calcium hydroxide Ca(OH
In order to activate theatrical discourse aware of the changes imposed by the nature of the contemporary child in terms of stimulating the social skills that achieve a technical and aesthetic convergence between him and theatrical presentation by investing the fact of the existence of the child and its potential in the weaving of stories, and folk in the imagination, and simulation of what corresponds with the characters and icons interact with them through technologies In the light of this research came the following address: (ways to stimulate the skills of the child through a contemporary theatrical speech) where the researcher seeks to delineate the importance involved in the discourse of theater through ways to reach the pillars con
... Show MoreThis research introduce a study with application on Principal Component Regression obtained from some of the explainatory variables to limitate Multicollinearity problem among these variables and gain staibilty in their estimations more than those which yield from Ordinary Least Squares. But the cost that we pay in the other hand losing a little power of the estimation of the predictive regression function in explaining the essential variations. A suggested numerical formula has been proposed and applied by the researchers as optimal solution, and vererifing the its efficiency by a program written by the researchers themselves for this porpuse through some creterions: Cumulative Percentage Variance, Coefficient of Determination, Variance
... Show MoreIn this study, two correlations are developed to calculate absolute rocks permeability from core samples tested by Gas Permeameter Apparatus. The first correlation can be applied if K g≤100, the second correlation can be applied if Kg>100. Sixty core samples having different permeabilities to give a wide range of values that necessary to achieve a correlation.
The developed correlation is easily applied and a quick method to avoid repeating the test at different pressure values. Only one pressure test is required to reach absolu
... Show MoreA recurrent condition that affects up to 10% of people worldwide is gastric ulceration illness. The existence of gastric juice pH with the lowering of mucous defences is prerequisites for the development of chronic ulcers. The main variables affecting the mucosa susceptibility to damage include Helicobacter pylori (H. pylori) infections or non-steroidal anti-inflammatory medicines (NSAIDs). Proton pump inhibitors (PPIs) including histamine-2 (H2) receptor inhibitors, two common therapies for peptic ulcers, have been linked to side impacts, recurrence or a variety of pharmacological combinations. Conversely, therapeutic herbs or the chemicals they contain may be used to cure or eliminate a wide range of illnesses. Therefore, prominent pharma
... Show MoreThe research deals with one of the urban problems facing cities, namely the existence of neglected urban spaces that need to be activated , These spaces give a negative image of the city, is not conducive to life and social interactions or the city has a one distinctive urban experience, leading to a reduction peoples' confidence in revisiting of those areas, hinder the rest of the activities in that region . Because these spaces are of the basic components of the city and give it its identity through the elements and entities that constitute it , The idea of research emerged in the reclaiming of these spaces within contemporary urban trends and the activation of flexible , short-term and inovation for that purpose with
... Show MoreAfter the fall of the Iraqi regime in the 9th of April 2003, and after the disintegration of the country, political and party political chaos that had never been witnessed before, has now taken over. In the past 2 years, the American military forces had a primary role in spreading this chaos and disorder by applying a set of wrong measures and policies. This chaos that is still affecting the iraqi people was completely ignored by the USA even 2 years after the occupation, no serious steps have been taken in order to bring back order and security, on the other hand, most of the government institutions and its forces were disintegrated, along with the decision made by Paul Bremer of dismissing all the iraqi journals and the workers of the
... Show MoreIn this paper, a new class of nonconvex sets and functions called strongly -convex sets and strongly -convex functions are introduced. This class is considered as a natural extension of strongly -convex sets and functions introduced in the literature. Some basic and differentiability properties related to strongly -convex functions are discussed. As an application to optimization problems, some optimality properties of constrained optimization problems are proved. In these optimization problems, either the objective function or the inequality constraints functions are strongly -convex.