Whirling prediction with geometrical shaft profiling

Distributed parameter shaft–rotor models are considered. The multivariable irrational, hyperbolic and circular function, input–output relationship for the system, is derived. Arbitrary, geometrical shaft profiling may be accommodated within the analytical techniques outlined. Conventional frequency response methods are employed in the determination of the critical speed condition. Specific studies, incorporating cantilevered rotors with non-linear shaft length–diameter configurations are detailed. The general applicability of the procedures outlined is emphasised.     

Effect of different antibiotics on aerobic pathogenic bacteria and urinary tract infection in Al-Manathera City, Iraq: a comparative study

The present study was carried out from January to June 2011 in Al-Manathera General Hospital in Al-Manathera City, Iraq. The study aimed at comparing between bacteriological etiologic agents of otitis media and urinary tract infection (UTI). The study revealed that, from the 130 specimens from outpatients (65 ear swab from patients infected with otitis media and 65 urine specimens from patients infected with UTI), there were 60 bacterial isolates from patients infected with otitis media (36 males, 60 %, and 24 females, 40 %) with five no-growth specimens. Pseudomonas aeruginosa was the most prevalent bacteriological etiologic agent of otitis media (25 isolates, 41.666 %), while from the 65 urine specimens from patients suffering from UTI, there were 65 bacterial isolates (24 males, 36.923 %, and 41 females, 63.077 %). Klebsiella pneumoniae was the most prevalent etiologic agent of UTI (27 isolates, 41.53 %). Nitrofurantoin was active against all the otitis bacterial isolates and the UTI isolates, while Ampicillin and Penicillin were not active against most of bacterial isolates.     

Machine tool modelling and profile following performance

The axis drive of a milling machine is considered. Modelling methods enabling the inclusion of the dynamics of the relatively lumped and physically dispersed elements of the system are proposed. A model of the x-axis drive of the machine tool system is constructed. The responses of the system to deterministic inputs under profile following conditions are presented. Machine tool error, tracking accuracy, and surface finish predictions are investigated. Adverse machining operations are identified following geometrical, input signal, amplitude and frequency changes.     

The dynamics of cyclic ventilation systems

Ventilation and air conditioning modelling methods, for large scale, spatially dispersed systems are considered. The limitations of existing techniques are discussed and proposals for the application of novel analysis approaches are outlined. The use of hybrid, distributed–lumped parameter procedures enabling the incorporation of the relatively concentrated and significantly dispersed, system elements, is advocated. A dynamic model for a ventilation arrangement comprising inlet and exhaust fans, with filtered air re-circulation and air conditioning units is presented. Pressure, flow and temperature predictions within the system are computed following input and disturbance changes. The employment of the model for automatic, multivariable controller design purposes is commented upon.