Cantilever beams are used in many crucial applications in machinery and construction. For example, the airplane wing, the microscopic probe for atomic force measurement, the tower crane overhang and twin overhang folding bridge are typical examples of cantilever beams. The current research aims to develop an analytical solution for the free vibration problem of cantilever beams. The dynamic response of AISI 304 beam represented by the natural frequencies was determined under different working surrounding temperatures ((-100 ℃ to 400 ℃)). A Matlab code was developed to achieve the analytical solution results, considering the effect of some beam geometrical dimensions. The developed analytical solution has been verified successfully with real experimental data and the error was not exceeded 1%. Keywords: analytical solution, cantilever beam, free vibration, mathematical modeling.
Electronic University Library: Reality and Ambition Case Study Central Library of Baghdad University
Surfaces quality is one of the most specified customer requirements for machine parts. The major indication of surfaces quality on machined parts is surface roughness. The research aim is to study the cutting conditions and their effects on the surface roughness. This paper utilizes regression models to predict surface roughness over the machining time for variety of cutting conditions in turning. In the experimental part for turning, different types of materials (Aluminum alloy, Copper alloy, and Gray cast iron) were considered with different cutting speed ( ) and feed rate ( ). A mathematical Model depending on statistical-mathematical method between surface roughness (Rz ) and cutting condition ( , ) were derived, for the three materials
... Show Moreto evaluate the effect of various Nd:YAG frequency doubled laser parameters on the acid
dissolution and the progression of in vitro caries like lesions in human enamel.
Materials and Methods: Human extracted caries free upper first premolar teeth were collected for
this study. The irradiated teeth were divided into two groups. The first group was irradiated with
continuous Nd:YAG laser radiation, and the second group was irradiated with chopped Nd:YAG laser
radiation. For the first group, power and exposure time were changed while for the second group
power and number of pulses were changed. The spot diameter was kept constant for all the samples.
Results: using 1.5 W and 3 seconds (exposure time), best results among
Background Molluscum contagiosum is skin disease caused by the molluscum contagiosum virus (MCV) usually causing one or more small dome shaped umbilicated papules with symptoms that maybe self-resolve. MCV was once a disease primarily of children, but it has evolved to become a sexually transmitted disease in adults. It is believed to be a member of the pox virus family. In addition to the classic presentation of the disease; it can also come in different clinical forms that simulate large number of dermatolological disease.
Objective: To study different clinical forms of Molluscum contagiosum presentation in different age groups of Iraqi patients.
Method:This clinical descriptive study was performed in the outpatient department of
Normal thyroid function is essential for neonatal growth and brain development. In a newborn infant with severe disease, endocrine regulation of hormones can be affected by abnormal metabolism. The assessment of thyroid parameters results in the recognition of a dysfunction and its association with disease severity
Objectives: The purpose of the study is to ascertain the relationship between the training program and the socio-demographic features of patients with peptic ulcers in order to assess the efficiency of the program on patients' nutritional habits.
Methodology: Between January 17 and October 30 of 2022, The Center of Gastrointestinal Medicine and Surgery at Al-Diwanyiah Teaching Hospital conducted "a quasi-experimental study". A non-probability sample of 30 patients for the case group and 30 patients for the control group was selected based on the study's criteria. The study instrument was divided into 4 sections: the first portion contained 7 questions about demographic information, the second sect
... Show MoreAbstract. In this work, Bi2O3 was deposited as a thin film of different thickness (400, 500, and 600 ±20 nm) by using thermal oxidation at 573 K with ambient oxygen of evaporated bismuth (Bi) thin films in a vacuum on glass substrate and on Si wafer to produce n-Bi2O3/p-Si heterojunction. The effect of thickness on the structural, electrical, surface and optical properties of Bi2O3 thin films was studied. XRD analysis reveals that all the as deposited Bi2O3 films show polycrystalline tetragonal structure, with preferential orientation in the (201) direction, without any change in structure due to increase of film thickness. AFM and SEM images are used to investigate the influences of film thickness on surface properties. The optical measur
... Show MoreAniline and its derivatives are common contaminants in various wastewaters and represent a serious worry for societies health and a challenge to ecologists due to their dangers effects on to the human health.
ZSM-5 zeolite was prepared from locally available materials (kaolin and rice husk) for adsorption of aniline from synthetic wastewater. Characterization of the prepared zsm-5, kinetics and thermodynamic of the adsorption process were investigated.
The characterization results of the prepared zsm-5 zeolite showed that the surface area was 270.1 m2/g and pore volume 0.21828 cm3/g. The silica to alumina ratio (Si/Al) was 166. 47 and the sodium content was 11 wt. %. The atomic force microscope (AFM)
... Show MoreLiver is considered as the first target for the toxic effects of toxins and other xenobiotics, and this can be attributed to its role as a site which receive all absorbed xenobiotics from the gastrointestinal tract and its role as a major site for biotransformation of xenobiotics. The present study was designed to evaluate the possible hepatoprotective effect of benfotiamine against CCl4-induced hepatotoxicity in rats. The study was conducted on 48 male albino rats; the animals were allocated into 8 groups (6 rats in each group) and treated as follow: 4 groups treated with oral doses of either normal saline, benfotiamine (100 mg/kg), thiamine (100 mg/kg), N-acetylcystein (400 mg/kg) only without induction of hepatic damage. Th
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