A comprehensive practical study of typical mechanical properties of welded Aluminum alloy AA7020-T6 (Al-Mg-Zn), adopting friction stir welding (FSW) technique and conventional metal inert gas (MIG) technique, is well achieved in this work for real comparison purposes. The essences of present output findings were concentrated upon the FSW samples in respect to that MIG ones which can be summarized in the increase of the ultimate tensile strength for FSW was 340 MPa while it was 232 MPa for MIG welding, where it was for base metal 400 MPa. The minimum microhardness value for FSW was recorded at HAZ and it was 133 HV0.05 while it was 70 HV0.05 for MIG weld at the welding metal. The FSW produce 2470 N higher than MIG welding in the bending t

In the present study, a powder mixture of elements Ti and Ni was mechanically alloyed in a high energy ball mill. Microstructure of the nanosized amorphous milled product in different stages of milling has been characterized by X- ray diffraction, scanning electron microscopy and differential thermal analysis. We found that time of mechanical alloying is more significant to convert all crystalline structure to the amorphous phase. Nanocrystalline phase was achieved as a result of the mechanical alloying process. The results also indicates that the phase transformation and the grain size occurs in these alloys are controlled by ball milling time

      In this research, a variable stiffness actuator is proposed to enhance the damping of the mechanical vibrating system. The frequency response analysis of the vibrating system is dependant in order to analyze and synthesis this semi-active damping, where the suggested process is using active filter to estimate the present frequency of the vibration system, and this will limit the value of the stiffness of the vibrated system. Two active filter s are needed, low-pass-filter (LPF) to choose the higher stiffness of the actuator at small frequencies as well as more damping and high-pass-filter (HPF) to choose the lower stiffness of the actuator at high frequencies as well as more damping, and so

The different parameters  on  mechanical  and  microstructural  properties  of  aluminium  alloy  6061-T6 Friction  stir-welded  (FSW) joints  were investigated in the  present study. Different welded  specimens were produced by employing variable rotating  speeds and welding speeds. Tensile strength of the produced joints  was tested at room  temperature and the the effecincy was assessed, it was 75% of the base metal at rotational speed 1500 rpm and weld speed 50 mm/min. Hardness of various zones of FSW welds are presented and  analyzed by  means of  brinell hardness number . Besides to thess tests the bending properties  investigat

         The world's population growth and the increasing demand for new infrastructure facilities and buildings , present us with the vision of a higher resources consumption, specially in the form of more durable concrete such as High Performance Concrete (HPC) . Moreover , the growth of the world pollution by plastic waste has been tremendous. The aim of this research is to investigate the change in mechanical properties of HPC with added waste plastics in concrete. For this purpose 2.5%, 5% and 7.5% in volume of natural fine aggregate in the HPC mixes were replaced by an equal volume of Polyethylene Terephthalate (PET) waste , got by shredded PET bottles. The mechanical propert

Objectives: This study explored knowledge, attitude, and practice of infection control by dental students at College of Dentistry/ University of Baghdad, Iraq. Material and Methods: Three hundred dental students participated in this study. A self administrated questionnaire with 21 close ended questions related to use of personal protective equipments, infection control awareness, vaccination status, percutaneous exposures, and attitude towards treatment of patients with hepatitis B (HBV)/ or human immunodeficiency virus (HIV) was distributed to dental students. Data were analyzed using Statistical Package for Social Sciences (SPSS) version 21. Fisher exact and Chi-square test were used with significance level set to 0.05. Results: The

Hierarchical temporal memory (HTM) is a biomimetic sequence memory algorithm that holds promise for invariant representations of spatial and spatio-temporal inputs. This article presents a comprehensive neuromemristive crossbar architecture for the spatial pooler (SP) and the sparse distributed representation classifier, which are fundamental to the algorithm. There are several unique features in the proposed architecture that tightly link with the HTM algorithm. A memristor that is suitable for emulating the HTM synapses is identified and a new Z-window function is proposed. The architecture exploits the concept of synthetic synapses to enable potential synapses in the HTM. The crossbar for the SP avoids dark spots caused by unutil

This paper was aimed to evaluate the polyurethane (PU) and polyurethane/polyvinyl chloride (90 wt. % / 10 wt. %) as organic coating of carbon steel substrate against marine environment (3.5 wt.% NaCl aqueous solution) as a severe corrosion environment . The electrochemical impedance spectroscopy (EIS) and fitting impedance data by ZsimpWin 3.22 software were used to estimate the physical barrier of the samples for different exposure times. Different equivalent electrical circuits were proposed for the physical barrier at different immersion times to get appropriate fitting .Both PU and PU/PVC coatings showed excellent corrosion protection ability for steel .The PU/PVC coating showed better protection and stability than PU coating against