Flexible pavement design and analysis were carried out in the past with semi-experimental methods, using elastic characteristics of pavement layers. Due to the complex interferences between various layers and their time consumption, the traditional pavement analysis, and design methods were replaced with fast and powerful methods including the Finite Element Method (FEM) and the Discrete Element Method (DEM). FEM requires less computational power and is more appropriate for continuous environments. In this study, flexible pavement consisting of 5 layers (surface, binder, base, subbase, and subgrade) had been analyzed using FEM. The ABAQUS (6.14-2) software had been utilized to investigate the influence of the base layer depth on vertical stresses and displacements. Three different thicknesses were adopted (10, 20, and 30cm) with constant other pavement layer thicknesses. The results of this study showed that the stress levels at the top of the base layer increased by about 37% when the thickness of this layer increased from 10cm to 30cm, while the stress levels at the top of the subbase layer decreased by about 64%. When the base layer increased from 10 to 20, from 20 to 30, and from 10 to 30cm the vertical displacement decreased by 18%, 24%, and 37% respectively.
In this work, an anti-reflection coating was prepared in the region (400-1000) nm of wavelength, with a double layer of silicon dioxide (SiO2) as an inner layer and the second layer of the mixture (SiO2) and titanium dioxide (TiO2) with certain ratios, as an outer layer using the chemical spraying method with a number of 6 sprays of layer SiO2 and 12 sprays of layer SiO2 - TiO2. Using the method of chemical spraying deposited on the glass as a substrate with a different number of sprays of SiO2, and a fixed number of TiO2-SiO2. The optical and structural properties were determined using UV-Vis spectroscopy and atomic force mi
... Show MoreMicro-perforated panel (MPP) absorber is increasingly gaining popularity as an alternative sound absorber in buildings compared to the well-known synthetic porous materials. A single MPP has a typical feature of a Helmholtz resonator with a high amplitude of absorption but a narrow absorption frequency bandwidth. To improve the bandwidth, a single MPP can be cascaded with another single MPP to form a double-layer MPP. This paper proposes the introduction of inhomogeneous perforation in the double-layer MPP system (DL-iMPP) to enhance the absorption bandwidth of a double-layer MPP. Mathematical models are proposed using the equivalent electrical circuit model and are validated with experiments with good agreement. It is revealed that the DL-
... Show MoreCopper tin sulfide (Cu2SnS3) thin films have been grown on glass
substrate with different thicknesses (500, 750 and 1000) nm by flash
thermal evaporation method after prepare its alloy from their
elements with high purity. The as-deposited films were annealed at
473 K for 1h. Compositional analysis was done using Energy
dispersive spectroscopy (EDS). The microstructure of CTS powder
examined by SEM and found that the large crystal grains are shown
clearly in images. XRD investigation revealed that the alloy was
polycrystalline nature and has cubic structure with preferred
orientation along (111) plane, while as deposited films of different
thickness have amorphous structure and converted to polycrystalline
Nanomaterials have an excellent potential for improving the rheological and tribological properties of lubricating oil. In this study, oleic acid was used to surface-modify nanoparticles to enhance the dispersion and stability of Nanofluid. The surface modification was conducted for inorganic nanoparticles (NPs) TiO₂ and CuO with oleic acid (OA) surfactant, where oleic acid could render the surface of TiO2-CuO hydrophobic. Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM) were used to characterize the surface modification of NPs. The main objective of this study was to investigate the influence of adding modified TiO₂-CuO NPs with weight ratio 1:1 on thermal-physical propertie
... Show MoreOne of the major problems in modern construction is the accumulation of construction and demolition waste; this study thus examines the consumption of waste brick in concrete based on the use of blended nano brick powder as replacement for cement and as a fine aggregate. Seven concrete mixes were developed according to ACI 211.1 using recycled waste brick. Nano powder brick at 0, 5, and 10% was used as a replacement by cement weight, with other mixes featuring 10, 20, and 30% partial replacement by volume of river sand with brick. The experimental results for replacement of cement with nano brick powder showed an enhancement in mechanical properties (compressive, flexural, and tensile strength) at 7,
The development of human resources training programs has an applied and important role in the preparation of human cadresin terms of capacity to absorb technical sciences and skills and scientific and practical practices at faster rates in order to bealighed with continous development. Hence the recognition of the significant role that human resources play in the economy of any country,which has stressed the interest towards the economic unity of the qualified staff that it needsin atimely manner through the ongoing training process in the era of high technology day by day In this regard ,the current research deal with accounting of human resources and its impact on reducing costs in the military establishment and the
... Show MoreThis research has investigated the effect of the customer knowledge management CKM in sustainable promotion SP. The research conducted a quantitative method on a sample of employees in the Al-Furat State Company for Chemical Industries affiliated / the Ministry of Industry and Minerals in Iraq. The research’s problem presented a set of questions, one of the most important was (is there a relation and impact between the dimensions of customer knowledge management and sustainable promotion). The aim of the research is to identify the extent to which customer knowledge management activities are applied in understudy organization. This research adopted the questionnaire as a main instrument to collect information from (140) participants in
... Show MoreThe security environment for Northeast Asia is extremely important, as it includes most of the international actors (United States of America, China, Russian Federation and Japan), which gives the nature of the interactions of these forces a special importance for the region.
Because of the multiplicity of policies and interests of the active forces in the region, the result has been an unstable regional environment where the interests of the major powers often clash repeatedly on many related issues, which is coupled with the growing efforts of many powers to adopt policies that differ from what they did in the past This resulted in different patterns of relations, which were mainly characterized by competition over regional lea
... Show MoreTrajectory tracking and vibration suppression are essential objectives in a flexible joint manipulator control. The flexible joint manipulator is an under-actuated system, in which the number of control actions is less than the degree of freedom to be controlled. It is very challenging to control the underactuated nonlinear system with two degree of freedom. This paper presents a hierarchical sliding mode control (HSMC) for a rotary flexible joint manipulator (RFJM). Firstly, the rotary flexible joint manipulator is modeled by two subsystems. Secondly, the sliding surfaces for both subsystems are constructed. Finally, the control action is designed based on the Lyapunov function. Computer simulation results demonstrate the effectiveness of
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