Vibration and NPSHr (NPSH₃), improvement of BB1 two stage pump reliability

Case StudyThis case study discusses the impeller redesign of 10 8x15 BB1 two stages Amine pump in a Gas Sweeting Plant in Malaysia. The original pump was supplied in 1996 and after some design changes it had an history of recurring high vibration and impeller damages such as a cavitation erosion on inlet suction side and disk break at impeller outlet. Pump performance analysis revealed a service operative point close to Minimum Continuous Stable Flow showing vibration peak both on synchronous frequency and VPF (vane passing frequency) typical of secondary flow effect. After a FMEA analysis it was decided to redesign the impeller.CFD simulation and Static structural with pressure load profiles have been performed and a model test bench has been set up to compare new and old impeller design focusing on NPSHr curve and on interaction forces between impeller blades and volute lip. Currently the 10 pumps are operating without showing any vibration problem

Oxidative Stress-mediated Mesangial Cell Proliferation Requires RAC-1/Reactive Oxygen Species Production and β4 Integrin Expression

Abstract Lipid abnormalities and oxidative stress, by stimulating mesangial cell (MC) proliferation, can contribute to the development of diabetes-associated renal disease. In this study we investigated the molecular events elicited by oxidized low density lipoproteins (ox-LDL) in MC. We demonstrate that in MC cultured in the presence of ox-LDL, survival and mitogenic signals on Akt and Erk1/2 MAPK pathways are induced, respectively. Moreover, as shown by the expression of the dominant negative Rac-1 construct, we first report that ox-LDL-mediated cell survival and cell cycle progression depend on Rac-1 GTPase-mediated reactive oxygen species production and on epidermal growth factor receptor transactivation. By silencing Akt and blocking Erk1/2 MAPK pathways, we also demonstrate that these signals are downstream to Rac-1/reactive oxygen species production and epidermal growth factor receptor activation. Finally, by endogenous depletion of β4 integrin, expressed in MC, we provide evidence that the expression of this adhesion molecule is essential for ox-LDL-mediated MC dysfunction. Our data identify a novel signaling pathway involved in oxidative stress-induced diabetes-associated renal disease and provide the rationale for therapeutically targeting β4 integrin

p53 Mediates the Accelerated Onset of Senescence of Endothelial Progenitor Cells in Diabetes

Adverse metabolic factors, including oxidized small and dense low density lipoprotein (ox-dmLDL) can contribute to the reduced number and the impaired functions of circulating endothelial progenitors (EPC) in diabetic patients. To elucidate the molecular mechanisms involved, EPC from normal donors were cultured in the presence of ox-dmLDL. Under these experimental conditions EPC undergo to senescent-like growth arrest. This effect is associated with Akt activation, p21 expression, p53 accumulation, and retinoblastoma protein dephosphorylation and with a reduced protective effect against oxidative damage. Moreover, depletion of endogenous p53 expression by small interfering RNA demonstrates that the integrity of this pathway is essential for senescence to occur. Activation of the Akt/p53/p21 signaling pathway and accelerated onset of senescence are also detectable in EPC from diabetic patients. Finally, diabetic EPC depleted of endogenous p53 do not undergo to senescence-growth arrest and acquire the ability to form tube-like structures in vitro. These observations identify the activation of the p53 signaling pathway as a crucial event that can contribute to the impaired neovascularization in diabetes

Thermo-Structural Analysis Of Steam Tracing Arrangements Applied To Pump Barrels

LecturePumps steam tracing is widely used in Oil&Gas industry for critical services in which the process fluid requires a minimum temperature to avoid its crystallization during stand-by. This paper describes the process of utilizing Computational Fluid Dynamics to perform a thermo-structural analysis of a barrel pump to determine the optimal steam tracing arrangement to maintain a minimum internal temperature. The most critical part of the analysis was to define the Heat Transfer Coefficient of the entire system. The computations consisted in conjugate Computational Fluid Dynamics solutions involving the ambient temperature and wind distribution, the skid dimensions and arrangement (barrels materials), the tracing system (carbon steel piping), the insulation (Mineral Wool) and the fluid compartments, both steam inside the piping and air in the gaps. The steam was modelled as a single-phase fluid with properties defined to consider the latent heat of condensatio

A novel mechanism causing imbalance of mitochondrial fusion and fission in human myopathies.

Mitochondrial dynamics play an important role in cellular homeostasis and a variety of human diseases are linked to its dysregulated function. Here, we describe a 15-year-old boy with a novel disease caused by altered mitochondrial dynamics. The patient was the second child of consanguineous Jewish parents. He developed progressive muscle weakness and exercise intolerance at 6 years of age. His muscle biopsy revealed mitochondrial myopathy with numerous ragged red and cytochrome c oxidase (COX) negative fibers and combined respiratory chain complex I and IV deficiency. MtDNA copy number was elevated and no deletions of the mtDNA were detected in muscle DNA. Whole exome sequencing identified a homozygous nonsense mutation (p.Q92*) in the MIEF2 gene encoding the mitochondrial dynamics protein of 49 kDa (MID49). Immunoblotting revealed increased levels of proteins promoting mitochondrial fusion (MFN2, OPA1) and decreased levels of the fission protein DRP1. Fibroblasts of the patient showed elongated mitochondria, and significantly higher frequency of fusion events, mtDNA abundance and aberrant mitochondrial cristae ultrastructure, compared with controls. Thus, our data suggest that mutations in MIEF2 result in imbalanced mitochondrial dynamics and a combined respiratory chain enzyme defect in skeletal muscle, leading to mitochondrial myopathy

The Italian Draft Law on the \u2018Provisions Concerning the Safeguarding of the Intangible Cultural Heritage\u2019

Intangible cultural heritage in Italy is still in need of a unified approach, capable of providing reliable criteria for identifying its assets and for indicating timescales and means by which they should be safeguarded. In the continued absence of up-to-date, ad hoc state legislation (since the content of those laws which do implement international Conventions is too generic in nature to be sufficiently effective), the Regions have proceeded to act in a somewhat scattered manner, giving rise to an extremely fragmented and very disorderly regulatory framework. The draft law N. 4486, "Provisions Concerning the Safeguarding of the Intangible Cultural Heritage", presented on 12th May 2017 at the Chamber of Deputies of the Italian Republic - as the result of the work of an interdisciplinary and inter-university research team coordinated by Marco Giampieretti, who has drafted the final text with the collaboration of Simona Pinton - seeks to fill the serious void that exists in Italian legal system by aligning it to the principles of international and European law, by redirecting the relevant State and Regional legislation, and by satisfying the fundamental requirements of the national community

Gestione dei pazienti con scompenso cardiaco acuto in Medicina d'Urgenza e supporto dell'ecografia polmonare

Lo scompenso cardiaco è una patologia cronica progressiva molto comune, soprattutto nei soggetti anziani, rappresentando una delle principali cause di morbilità e mortalità nella popolazione mondiale. Le riacutizzazioni dello scompenso cardiaco sono frequenti e determinano numerosi ricoveri ogni anno, destinati a crescere a causa dell’aumento della prevalenza dello scompenso cardiaco, principalmente legato all’incremento della sopravvivenza. I pazienti che accedono in Pronto Soccorso con scompenso cardiaco acuto sono esaminati da un punto di vista clinico, laboratoristico e strumentale al fine di giungere a una diagnosi precoce, impostare una terapia adeguata e ottenere una prognosi favorevole. Lo scopo di questa tesi è stato quello di valutare la gestione dei pazienti con scompenso cardiaco acuto mediante l’utilizzo dell’ecografia polmonare e un’applicazione rigorosa delle più recenti linee guida nel gruppo prospettico, in confronto ai pazienti del gruppo retrospettivo in cui è stata applicata una gestione abituale. In questo studio abbiamo esaminato un totale di 58 pazienti con diagnosi di “scompenso cardiaco acuto”, ricoverati presso il reparto di Medicina d’Urgenza Universitaria dell’Azienda Ospedaliera Universitaria Pisana, a seguito di accesso presso il Dipartimento di Emergenza e Accettazione. Sono state analizzate retrospettivamente le cartelle cliniche di 38 pazienti dimessi tra il 1° gennaio 2021 e il 31 ottobre 2022, escludendo quelli con problematiche cliniche attive prevalenti sul quadro dello scompenso cardiaco acuto. In parallelo, è stato condotto un arruolamento prospettico di 20 pazienti, nel periodo compreso tra il 21 giugno e il 31 ottobre 2022, a loro volta suddivisi casualmente nel sottogruppo di studio e in quello prospettico. Nel sottogruppo di studio il dosaggio della terapia diuretica è stato titolato sulla base della quantità totale di linee B ottenute nelle immagini ecografiche, ovvero il LUS score. Nel sottogruppo di controllo invece la terapia diuretica è stata somministrata seguendo le indicazioni delle più recenti linee guida, pubblicate alla fine di Agosto 2021 in assenza (gruppo di controllo) o in assenza (gruppo ecografia) di informazioni sulla congestione polmonare derivaste da uno score basato sulla quantità totale di linee B ottenute in una ecografia toracica standardizzata. Di ciascun paziente sono stati analizzati i dati anamnestici, laboratoristici e strumentali dell’ecografia polmonare che sono stati raccolti in diversi momenti del decorso ospedaliero: all’accesso in DEA (T0), all’ammissione in reparto (T1), dopo 72 ore dall’ingresso in reparto (T72h) e alla dimissione (Tdim). Per valutare gli esiti del ricovero sono stati presi in considerazione il decesso e il riaccesso in DEA entro un mese dalla dimissione per scompenso cardiaco acuto. Per l’analisi di questo lavoro di tesi i pazienti dello studio prospettico sono stati considerati come unico gruppo indipendentemente dalla valutazione o meno dello score ecografico da parte del clinico nella decisione riguardo alla terapia diuretica. La popolazione valutata nel nostro studio di tesi è da considerare "real-life", sulla base dell’età molto avanzata (età media di 82,6 anni) e della presenza di molteplici comorbilità. Dai nostri risultati, è emerso che una percentuale rilevante della popolazione, pur con diagnosi di scompenso cardiaco cronico, non effettuava una terapia di base appropriata, elemento che potrebbe aver influito sulla riacutizzazione della patologia. La maggior parte dei pazienti presentava sintomi e segni di congestione, oltre ad avere una buona perfusione, ed è stata quindi classificata in Pronto Soccorso nella categoria WARM-WET. I risultati dei diversi parametri monitorati durante il decorso spedaliero nei 58 pazienti in esame mostrano come l’effetto della terapia diuretica, somministrata in dosi maggiori nelle prime fasi acute della gestione, determini un andamento in calo dei livelli di NT-proBNP e del LUS score. Tale evento è associato alla riduzione dello stato di congestione del paziente, ed è accompagnato dall’aumento del bilancio idrico in seguito all’incremento della diuresi indotto dalla terapia. Tuttavia, abbiamo registrato un aumento dei livelli di creatinina nella fasi acute della gestione, soprattutto nei pazienti del gruppo prospettico, come reazione avversa delle dosi elevate di diuretico somministrate per via endovenosa in questa prima fase. Oltre la metà dei pazienti che ha avuto un outcome negativo apparteneva al gruppo retrospettivo. Inoltre, quest’ultimi presentavano una durata minore della degenza, anch’essa associata a una prognosi sfavorevole. Alla dimissione, i valori elevati del NT-proBNP e del LUS correlavano con un maggior numero di outcomes negativi, seppure senza il raggiungimento di una significatività statistica, suggerendo come tali paramentri possano essere degli utili indicatori prognostici di eventi negativi. Invece in tale occasione, il riscontro di una frequenza cardiaca elevata e di bassi livelli pressori è risultato associato a un numero maggiore di eventi negativi, sostenendo che un mancato controllo della frequenza cardiaca e un persistente stato ipotensivo influiscono negativamente sul decorso dei pazienti con scompenso cardiaco. Alla luce di questi risultati, possiamo concludere che la gestione dei pazienti con scompenso cardiaco acuto guidata dall'ecografia non influisce negativamente sulla funzione renale ma determina degenze mediamente più lunghe, necessarie per una migliore stabilizzazione del paziente e un’adeguata risoluzione della congestione polmonare. L'ecografia polmonare costituisce quindi uno strumento utile per la diagnosi e il monitoraggio dei pazienti con scompenso cardiaco acuto. Infatti, nonostante le limitazioni dovute alla bassa numerosità dei pazienti presenti nel gruppo prospettico, i pazienti gestiti tramite l’ecografia polmonare hanno riportato percentuale inferiore di outcomes negativi. A tale scopo la prosecuzione dello studio, al fine di incrementare la casistica, potrà consentire di validare ulteriormente il ruolo dell'ecografia nel guidare il dosaggio della terapia diuretica

L10: A FEM Approach to Predict Acoustic Resonance in Multistage Centrifugal Pump

LecturesAcoustic resonance can develop within the hydraulic channels of the pump, especially in the long crossover channel of a multistagecentrifugal pump This phenomenon occurs when the hydraulic channel length is equal to the sound wavelength produced by theBlade Passage Frequency (BPF) The combination between the BPF and the wave reflection from a stage to the next, generates anamplification of pressure pulsation and eventually a higher vibration level in the pump This paper presents a Finite Element Method(FEM) approach to predict the acoustic resonance in multistage centrifugal pumps The 1-D method used to calculate the equivalentlength through the channel, assuming it as a straight pipe, has demonstrated in some cases that it is unable to predict the vibrationproblem related to the phenomenon of the acoustic resonance that occurred in the centrifugal pump test bench with complex 3-Dgeometry, therefore the study of a new methodological approach began The most important parameter to be evaluated is theequivalent channel length which is the length of the sound wave path within a complex 3D geometry The FEM analysis performed byANSYS® for the calculation of harmonic resonance of the hydraulic channels has been used to predict the possible acoustic resonancein long crossover channels of API 610 BB3 (multistage centrifugal pump, axially split, between bearings) centrifugal pumps The useof Acoustic Analysis coupled with the Harmonic Analysis implemented in ANSYS® allows to simulate the wave propagation andreflection in a complex 3-D channel and obtain the harmonic response of the machine To validate the tool, several simulations havebeen done on BB3 pumps, already tested in the past: the analysis showed a very good correspondence between the FEM results andthe vibration reports of real pump tests The new procedure was able to verify both the pumps that showed vibration problems and thepumps without problems A detailed case study also demonstrated that the accuracy of the analysis method can detect the change insystem behavior when a change in fluid temperature is measured After this series of simulations and comparative analysis, the newapproach has become the standard procedure for detecting vibration problems related to the acoustic resonance during the designphase and avoiding possible issues in the witnessed performance tes

PL05 - A FEM APPROACH TO PREDICT ACOUSTIC RESONANCE IN MULTISTAGE CENTRIFUGAL PUMP

LectureAcoustic resonance that can develop within the hydraulic channels of the pump, especially in the long crossover channel of a multistage, has always had in the past a minimal consideration if compared with other dynamic behaviors. A possible issue on field, not intercepted during the development phase of a new machine, has become the occasion for an improvement of the design procedure. A fundamental factor in the development of this new method is the increase in computational capacity. The design procedure moved from a simple spreadsheet where it was possible to implement a simple one-dimensional geometry to a FEM calculation that represented the real geometry in all its three-dimensional complexity and that compared with experimental tests shows the excellent predictability

PL05 - A FEM APPROACH TO PREDICT ACOUSTIC RESONANCE IN MULTISTAGE CENTRIFUGAL PUMP

LectureAcoustic resonance that can develop within the hydraulic channels of the pump, especially in the long crossover channel of a multistage, has always had in the past a minimal consideration if compared with other dynamic behaviors. A possible issue on field, not intercepted during the development phase of a new machine, has become the occasion for an improvement of the design procedure. A fundamental factor in the development of this new method is the increase in computational capacity. The design procedure moved from a simple spreadsheet where it was possible to implement a simple one-dimensional geometry to a FEM calculation that represented the real geometry in all its three-dimensional complexity and that compared with experimental tests shows the excellent predictability