Identification of nonlinear vibrating structures: Part I -- Formulation

A self-starting multistage, time-domain procedure is presented for the identification of nonlinear, multi-degree-of-freedom systems undergoing free oscillations or subjected to arbitrary direct force excitations and/or nonuniform support motions. Recursive least-squares parameter estimation methods combined with nonparametric identification techniques are used to represent, with sufficient accuracy, the identified system in a form that allows the convenient prediction of its transient response under excitations that differ from the test signals. The utility of this procedure is demonstrated in a companion paper

Identification of nonlinear vibrating structures: Part II -- Applications

A time-domain procedure for the identification of nonlinear vibrating structures, presented in a companion paper, is applied to a "calibration" problem which incorporates realistic test situations and nonlinear structural characteristics widely encountered in the applied mechanics field. The "data" set is analyzed to develop suitable, approximate nonlinear system representations. Subsequently, a "validation" test is conducted to demonstrate the range of validity of the method under discussion. It is shown that the procedure furnishes a convenient means for constructing reduced-order nonlinear nonparametric mathematical models of reasonably high fidelity in regard to reproducing the response of the test article under dynamic loads that differ from the identification test loads

Experimental set-up for investigation of fault diagnosis of a centrifugal pump

Centrifugal pumps are complex machines which can experience different types of fault. Condition monitoring can be used in centrifugal pump fault detection through vibration analysis for mechanical and hydraulic forces. Vibration analysis methods have the potential to be combined with artificial intelligence systems where an automatic diagnostic method can be approached. An automatic fault diagnosis approach could be a good option to minimize human error and to provide a precise machine fault classification. This work aims to introduce an approach to centrifugal pump fault diagnosis based on artificial intelligence and genetic algorithm systems. An overview of the future works, research methodology and proposed experimental setup is presented and discussed. The expected results and outcomes based on the experimental work are illustrated

Evaluation the Pollution of Sediments of the Shatt Al-Hillah with Heavy Metals by Using the Pollution Indices

اهتمت  هذه  الدراسة بتقييم مستوى  تراكيز الملوثات  من المعادن الثقيلة التالية  (Hg، Pb V، Cr، Co، Ni، As، Rb، Sr، Zr، Mo، Cu، Zn، Th، U)، لرواسب من ضفاف شط الحلة .أجريت الدراسة في قسم علم الأرض في كلية العلوم ، جامعة بابل ، تم جمع 14 عينة من الرواسب من ضفاف نهر شط الحلة اظهرت نتائج الفحوصات ان  متوسط ​​تركيز المعادن الثقيلة في رواسب ضفاف النهر بالترتيب التنازلي: Sr (360.6) السنترونشيوم  ، Cr (285.9)  الكروم،  النيكلNi (203.2 ، Co (169.9  الكوبلت Zr (166.3  الزركونيوم ،  الفناديوم V. (116.4)، Zn (91.6) الخارصين ،  النحاس Cu (48.8)، Rb (41.9) الروبيديوم ،  الرصاص Pb (18.1)،  As الزرنيخ  (11.1)، Hg الزئبق  (5.7)،  الثوريوم Th (4.2  الموليبدنوم Mo (3.7) ،  U  اليورانيوم (2 (ملغرام/لتر) ، وكان مؤشر التراكم  (Igeo) للزئبق لخمس محطات على طول النهر أكبر من 3.0 ، والذي يشير إلى تلوث الترسبات بدرجة عالية بهذا العنصر .  وكان مؤشر التراكم  (Igeo)  لعنصر النيكل (Ni) في  12 موقعاً  ولعنصر الكوبلت في 12 موقعا أكبر من 1.0 ، يشير إلى مستوى معتدل من التلوث لرسوبيات ضفاف النهر  ، تراوحت قيمة مؤشر حمل التلوث (PLI) لمحطات أخذ العينات الإجمالية من 0.7 إلى 1.4.The level of pollutant of heavy metals (Hg, Co,  Pb V, Cr, Ni, Sr, Zr, Mo, Cu, Rb,  Zn, As,Th, U) , in the sediment samples on the banks of the Shatt al-Hillah River The study was conducted in the Department of Earth Science at the collge  of Science, University of Babylon, 14 samples of sediments  ware collected from the banks of the river of Shatt Al-Hillah. The average concentration of the heavy metal  in the sediment of the river bank  in descending order: Sr (360.6 ppm) ,Cr (285.9 ppm ), Ni (203.2 ppm), Co (169.9 ppm), Zr (166.3 ppm),. V (116.4ppm) , Zn (91.6 ppm), Cu (48.8 ppm ), Rb (41.9 ppm ), Pb (18.1 ppm), As(11.1 ppm), Hg(5.7ppm),Th (4.2 ppm),Mo(3.7 ppm), U(2ppm,. The geoaccumulation index (Igeo) for H

Spectrophotometric Determination of Paracetamol in bulk and Pharmaceutical Preparations

A simple, and rapid spectrophotometric method for the estimation of paracetamol has been developed. The methods is based on diazotisation of 2,4-dichloroaniline followed by a coupling reaction with paracetamol in sodium hydroxide medium. All variables affecting the reaction conditions were carefully studied. Beer's law is obeyed in the concentration range of 4-350 ?gml?1 at 490 nm .The method is successfully employed for the determination of paracetamol in pharmaceutical preparations. No interferes observed in the proposed method. Analytical parameters such as accuracy and precision have been established for the method and evaluated statistically to assess the application of the method

Occurrence of functional single-lobed ovary in Cirrhinus mrigala (Hamilton,1822) brood fish from Assam, India

Occurrence of abnormally developed gonads in fish is rather more uncommon in freshwater fish than marine fish. It is therefore worthwhile to disseminate the information of occurrence of a single-lobed ovary in Cirrhinus mrigala brood fish as an abnormal phenomenon. During April 2011 to March 2013, around 500 brood fish samples of Indian major carps (Labeo rohita, Catla and C. mrigala) were collected from different government and private fish farms of Assam and Tripura located in the Northeast of India. Among them, one C. mrigala specimen measuring 41 cm in total length and 640 g in weight collected from Ulubari fish seed farm of Guwahati, Assam during June, 2012 was found to have a single-lobed ovary instead of the normal bilobed structure. The ovary occupied the entire body cavity and the majority of ova were round and translucent. The ovary contributed substantially to the total body weight with gonado-somatic index of 32.81 which was the highest among all the mrigal specimens examined. The study indicates possibility of artificially inducing development of single-lobed ovary in C. mrigala for achieving possible higher spawn outputs in induced breeding of the cultivable species

Collective autobiographical reflexivity on active and compassionate citizenship in the COVID-19 crisis

Since the outbreak of the coronavirus pandemic, socio-economic inequalities have become exacerbated and COVID-19 related hate crimes have increased. This paper explores how citizenship education might be reimagined in response to this context, with the vision of rebuilding a more equitable and compassionate society. By using a collective autobiographical writing approach, this study documented six different autobiographical reflexivities of citizenship education scholars who were from different parts of the world: China, South Korea, the Philippines, the United States, Nepal and the United Kingdom. It also observed the way the pandemic played out in the location where they were situated during the research as well as how it played out in their countries of origin, and further, how it affected the civic development in each context. The scholars' range of autobiographical expressions resulted in insights for developing a type of citizenship education, namely, education for active and compassionate citizenship