In this paper, a new equivalent lumped parameter model is proposed for describing the vibration of beams under the moving load effect. Also, an analytical formula for calculating such vibration for low-speed loads is presented. Furthermore, a MATLAB/Simulink model is introduced to give a simple and accurate solution that can be used to design beams subjected to any moving loads, i.e., loads of any magnitude and speed. In general, the proposed Simulink model can be used much easier than the alternative FEM software, which is usually used in designing such beams. The obtained results from the analytical formula and the proposed Simulink model were compared with those obtained from Ansys R19.0, and very good agreement has been shown. It was found that the maximum vibration occurs when the load speed is about 0.58 of the critical speed of the beam. Furthermore, the vibration amplitude resulting from a moving load can amplify to 1.65 times the deflection produced by an equivalent static load.
Abstract
Friction stir welding is a relatively new joining process, which involves the joining of metals without fusion or filler materials. In this study, the effect of welding parameters on the mechanical properties of aluminum alloys AA2024-T351 joints produced by FSW was investigated.
Different ranges of welding parameters, as input factors, such as welding speed (6 - 34 mm/min) and rotational speed (725 - 1235 rpm) were used to obtain their influences on the main responses, in terms of elongation, tensile strength, and maximum bending force. Experimental measurements of main responses were taken and analyzed using DESIGN EXPERT 8 experimental design software which was used to develop t
... Show MoreA metal-assisted chemical etching process employing p-type silicon wafers with varied etching durations is used to produce silicon nanowires. Silver nanoparticles prepared by chemical deposition are utilized as a catalyst in the formation of silicon nanowires. Images from field emission scanning electron microscopy confirmed that the diameter of SiNWs grows when the etching duration is increased. The photoelectrochemical cell's characteristics were investigated using p-type silicon nanowires as working electrodes. Linear sweep voltammetry (J-V) measurements on p-SiNWs confirmed that photocurrent density rose from 0.20 mA cm-2 to 0.92 mA cm-2 as the etching duration of prepared SiNWs increased from 15 to 30 min. The
... Show MoreBackground: The vaginal microbial ecosystem stability preclude many other organisms but sometimes the vaginal micro biota is disturbed and this cause change in the normal
balance causing symptoms of vulvuvaginitis like abnormal or increased vaginal discharge, redness and itching.
Objective: To prove C. albicans presence in their vagina clinically and laboratory by culture of vaginal swab on two media.
Type of the study: This study is a case control study
Methods: This study is a case control study in which 100 clinically patient women admitted to maternity hospital in kalar city and khanaqin hospital during the pe
... Show MoreThe aim of the present study is to formulate, evaluate and characterize the nanoemulsion of Domperidone a poorly water-soluble anti-emetic drug.
Domperidone powder is white or almost white powder, photosensitive, practically insoluble in water, slightly soluble in ethanol and in methanol; soluble in dimethylformamide. It is used as an antiemetic for the short-term treatment of nausea and vomiting of various etiologies.
Solubility studies were conducted to select the oil, surfactant and cosurfactant. Phase diagrams were constructed by aqueous phase
... Show MoreAnise and thyme crude extract were used to prepare a lotion for topical application due to their antimicrobial, germicidal and antifungal effects. Two formulas were prepared using the mentioned natural plants, formula 2 (selected lotion) was the most acceptable one which contained veegum and xanthan gum as suspending agents in addition to other exceipients providing it good properties with high physical stability because of its flocculating, pouring, resuspending easily with sedimentation volume (F) 0.96. In addition to unchangeable odor and color with expiration date of one year. While the Preliminary clinical study was done using this lotion on 10 patients with infecious viral skin diseases, it was found that this lotion was successful
... Show MoreCutaneous Leishmaniasis (CL) is an endemic disease and one of the major health problems in Iraq. Leishmania tropica is known as the causative agent of Cutaneous Leishmaniasis in Baghdad.The classical serological methods of diagnosing leishmaniasis is a poor sensitivity especially for the sub genus and time consuming Here we have investigated two primer pairs, one specific for Leishmania as genus and the primer specific for the species of L. tropica to be detected by polymerase chain reaction (PCR).Samples were collected from (AL-karama Teaching Hospital) and whole genomic DNA was extracted from axenic promastigotes.The extracted DNA was amplified by PCRwith two KDNA primer pairs, for genus specific (13A/13B) and (Lmj4/Uni21) to identify
... Show MoreThe LiCoMnO4 spinel compound was prepared by a sol–gel method. Structural measurements were utilized to investigate the characteristics of LCMO powder. The powder crystallizes in the space group Rd-3m, with a trigonal crystallinity structure, according to XRD analysis (hexagonal axes). SEM images showed that the crystalline grains sizes were about 200 nm - 350 nm, which provides large surface area. The sample had soft magnetic characteristics, according to hysteresis behaviour analysis in the Vibrating Sample Magnetometer (VSM). The prepared material is thought to be a candidate for the applications of energy storage in lithium-ion batteries.
Passive optical network (PON) is a point to multipoint, bidirectional, high rate optical network for data communication. Different standards of PONs are being implemented, first of all PON was ATM PON (APON) which evolved in Broadband PON (BPON). The two major types are Ethernet PON (EPON) and Gigabit passive optical network (GPON). PON with these different standards is called xPON. To have an efficient performance for the last two standards of PON, some important issues will considered. In our work we will integrate a network with different queuing models such M/M/1 and M/M/m model. After analyzing IPACT as a DBA scheme for this integrated network, we modulate cycle time, traffic load, throughput, utilization and overall delay
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