Subsynchronous Shaft Vibration in an Integrally Geared Expander-Compressor due to Vortex Flow in an Expander

Lectur

Bertrand-Edgeworth Equilibrium in Oligopoly

This paper investigates simultaneous move capacity constrained price competition game among three firms. I find that equilibria in an asymmetric oligopoly are substantially different from those in the duopoly and symmetric oligopoly. I characterize mixed strategy equilibria and show there exist possibilities of i) the existence of a continuum of equilibria ii) the smallest firm earning the largest profit per capacity and iii) non-identical supports of equilibrium mixed strategies, all of which never arise either in the duopoly or symmetric oligopoly. In particular, the second finding sheds light on a completely new pricing incentive in Bertrand competitions

Subsynchronous Shaft Vibration in an Integrally Geared Expander-Compressor due to Vortex Flow in an Expander

LecturesSubsynchronous shaft vibration was observed in an integrally geared expander-compressor when the machine was operated with a partial load in the course of plant start up. The root cause of the synchronous shaft vibration was identified, by means of CFD analysis, as the vortex flow which was generated in the downstream piping of the gas expander wheel. OEM installed an object, called “vortex breaker”, in the piping in order to eliminate the excitation force of the vortex flow, and as the result, the subsynchronous shaft vibration disappeared. This paper provides the detailed shaft vibration data, root cause analysis, countermeasure and the result from the countermeasure

Developmental experiences related to retirement from sport:insights from Japan

Psychological support systems for retiring elite athletes can assist them in making career transitions out of sport. The purpose of this study is to further advance research in this area, with a specific focus the developmental experiences related to the sport career transition process in Japan. One retired Olympic medalist was analyzed with a life story analysis method. The findings highlight the psychological difficulties experienced by retiring athletes and the system requirements to help them make an optimal transition

A Comparison of Manufacturing Methods, Accuracy, Quality Control and Testing Methods a They Relate to High Head Low Flow Impeller Efficiency and Overall Compressor Performance

LectureThis paper presents a detailed analysis and evaluation of impeller efficiency and overall compressor performance as they relate to specific impeller manufacturing methods, manufacturing tolerances, and quality control. The manufacturing process used in the construction of an impeller has a direct influence on the impeller’s performance The authors explain and compare different manufacturing methods and introduce the Taguchi Method Application as an available tool for statistical evaluation of key manufacturing parameters influence on impeller performance. As a best practice, manufacturing techniques for one piece impeller production are presented. In the case of high pressure centrifugal compressor applications with very narrow tip width impellers, and corrosive gas applications requiring special materials, EDM (Electrical Discharge Machining) and ECM (Electrolytic Machining) can be applied as a manufacturing process to improve quality control over conventional manufacturing methods. In response to a compressor performance discrepancy encountered during OEM FAT, a review was initiated into improving quality control and performance prediction based on enhanced impeller manufacturing processes for narrow tip width impellers. In this analysis, two compressor rotors are evaluated and compared; the first using traditional, two piece welded impellers and the second with one piece impellers machined via EDM and ECM. The resulting data from both series of tests suggests a significant improvement in individual impeller performance, as well as overall compressor performance for the single piece impeller compared to the two piece impeller

Shipping Digitalization and Automation for the Smart Port

Shipping, like most industries, is undergoing a digital transformation process which influences existing business models and operational practices, in a multifaceted way. Today, the shipping business context has been changing to incorporate further social demands, environmental, innovation and sustainability priorities, into fundamental shipping strategies, while taking advantage of technological advancements. In the era of Industry 4.0, which constitutes a recent evolution of advanced communications and information technologies and further promotes sustainable, human-centric, and resilient business development strategies, shipping and port entities need to embrace a broader perspective and a deeper understanding of various elemental technologies, namely: Artificial Intelligence, Blockchain, Cloud Computing, Big Data, and Physical Internet, in addition to core maritime logistics matters. This chapter proposes a descriptive framework of shipping digitalization and port automation, while providing a review of related technologies and business approaches, also international initiatives, for automation in global ports. Hence the chapter offers insights for business practitioners to steer through the current challenging global environment, also for policy makers to gain a more informed understanding of maritime logistics developments, towards necessary coordination and oversight mechanisms implementation

Emphysematous Cystitis in a Patient with Type 2 Diabetes Mellitus

A 62-year-old woman with a history of poorly controlled type 2 diabetes mellitus was admitted to our hospital with a 3-week history of mild fever, vomiting, and anorexia. Abdominal computed tomography (CT) showed bilateral hydronephrosis and gas accumulation in the urinary bladder wall and left ureter. Laboratory tests showed leukocytosis and elevated C-reactive protein level. Urine culture showed heavy growth of Escherichia coli. The final diagnosis was emphysematous cystitis. The patient was treated with systemic antibiotics and drainage using a urethral catheter. The clinical and radiographic findings resolved rapidly, and she was discharged from the hospital on day 28. Emphysematous cystitis is a relatively rare urinary tract infection associated with gas formation, and has the potential for a serious outcome if untreated. Early detection by imaging studies such as CT is important in providing prompt treatment and favorable clinical outcome

Atomic water channel controlling remarkable properties of a single brain microtubule: Correlating single protein to its supramolecular assembly

Microtubule nanotubesarefoundineverylivingeukaryoticcells;theseareformedbyreversible polymerizationofthetubulinprotein,andtheirhollow fibersare filledwithuniquelyarrangedwater molecules.Herewemeasuresingletubulinmoleculeandsinglebrain-neuronextractedmicrotubule nanowirewithandwithoutwaterchannelinsidetounraveltheiruniqueelectronicandopticalproperties for the firsttime.Wedemonstratethattheenergylevelsofasingletubulinproteinandsinglemicrotubule madeof40,000tubulindimersareidenticalunlikeconventionalmaterials.Moreover,thetransmittedac powerandthetransient fluorescencedecay(singlephotoncount)areindependentofthemicrotubule length.Evenmoreremarkableisthefactthatthemicrotubulenanowireismoreconductingthanasingle proteinmoleculethatconstitutesthenanowire.Microtubule's vibrationalpeakscondensetoasinglemode thatcontrolstheemergenceofsizeindependentelectronic/opticalproperties,andautomatednoise alleviation,whichdisappearwhentheatomicwatercoreisreleasedfromtheinnercylinder.Wehave carriedoutseveraltrickystate-of-the-artexperimentsandidentified theelectromagneticresonancepeaksof singlemicrotubulereliably.Theresonantvibrationsestablishedthatthecondensationofenergylevelsand periodicoscillationofuniqueenergyfringesonthemicrotubulesurface,emergeastheatomicwatercore resonantlyintegratesallproteinsarounditsuchthatthenanotubeirrespectiveofitssizefunctionslikea singleproteinmolecule.Thus,amonomolecularwaterchannelresidinginsidetheprotein-cylinderdisplays an unprecedentedcontrolingoverningthetantalizingelectronicandopticalpropertiesofmicrotubule

Subsynchronous Shaft Vibration in an Integrally Geared Expander-Compressor due to Vortex Flow in an Expander

LecturesSubsynchronous shaft vibration was observed in an integrally geared expander-compressor when the machine was operated with a partial load in the course of plant start up. The root cause of the synchronous shaft vibration was identified, by means of CFD analysis, as the vortex flow which was generated in the downstream piping of the gas expander wheel. OEM installed an object, called “vortex breaker”, in the piping in order to eliminate the excitation force of the vortex flow, and as the result, the subsynchronous shaft vibration disappeared. This paper provides the detailed shaft vibration data, root cause analysis, countermeasure and the result from the countermeasure