Dynamic response of a viscously damped two adjacent degree of freedom system linked by inerter subjected to base harmonic excitation

The study investigates the dynamic response of a viscously damped two adjacent single degree-of-freedom (2-ASDOF) system coupled by a connection that includes an inerter element. The dynamical model of a pair of simple oscillators coupled with various connection elements is synthetic but also representative to describe different classes of structures (i.e. contiguous buildings, adjacent walls and frames and so on). The specific kind of connection fundamentally alters the dynamic behavior of the entire system. Coupling elements typically studied are springs, dampers, linear or non-linear, passive, semi-active or active, e.g. [1,2]. The inerter is a novel device able to generate a resisting force, proportional to the relative acceleration of its terminals, equivalent to a force produced with an apparent (inertial) mass two orders of magnitude greater than its own physical (gravitational) mass [3]. In this study, a non-conservative connection, realized with a spring-inerter-viscous damper elements, adjusted in parallel, is considered as linking scheme for the 2-ASDOF system. In order to perform modal analysis, the first order state-space representation is adopted and the modal equations for the viscously damped system are derived. By solving the eigenvalue problem, the attention is focused on how modal parameters, i.e. the natural frequencies, the modal damping ratios and modes are affected by the connection. The system is then subject to harmonic base excitation and frequency response functions are depicted showing the influence of the link (through spring stiffness, inertance and damping coefficient) on the dynamic response. From the analysis with the different linking schemes, it emerges that the specific kind of connection influences the system dynamic characteristics

Vibration analysis of the civic tower in Rieti

In the last decades the definition of a suitable monitoring system for identifying the dynamic behavior of structures has had a central position in the civil engineering research area. The vibration analysis leads to the recognition of the reference state of structures which is essential to determine the integrity level when extreme events occur, such as earthquakes. The latest seismic events occurred in the world have shown the essential role of the new passive seismic techniques which aim to protect structures and the importance of supervising the building construction operations and the adopted improvement measures. In this work the structural monitoring of the civic tower located in Rieti is presented. In the tower a non-conventional TMD has been installed via an inter-story isolation system at the top floor by means of High Damping Rubber Bearings (HDRB). The general goal is to define a monitoring system suitable with this experimental case through the vibration analysis. Several aspects will be taken into account: the choice of sensors setup, the measured quantities and the extraction of structural information. Firstly this will allow to define the structure’s reference state featured by frequencies, damping ratios and mode shapes. Moreover the effective design of the monitoring system would lead to the characterization of the dynamic behavior of the structure equipped with a passive vibration control system. Different tests have been carried forward: ambient vibration test (AVT), forced vibration test (FVT) with vibrodyne and seismic test (ST). The AVT and the FVT enable to define the monitoring system and check the reliability of the adopted identification tools, among which an Output Only algorithm stands out: the Observer Kalman Filter System Id. On the other hand the ST will point out some preliminary information about the dynamic behaviour of the structure equipped with a non conventional Tuned Mass Damper referring it to higher levels of vibrations

Basi molecolari del medulloblastoma: ruolo delle E3-ligasi REN ed ITCH nel signaling di Hedgehog

Il medulloblastoma è la forma più comune di neoplasia infantile. È causato da alterazioni genetiche e epigenetiche che influenzano lo sviluppo delle cellule progenitrici dei granuli del cervelletto. Tali difetti comprendono delezioni cromosomiali, come la delezione del braccio corto del cromosoma 17, ed alterazioni nelle più importanti vie di trasduzione del segnale. È stato recentemente descritto che il medulloblastoma è strettamente legato all’attivazione costitutiva della pathway Sonic-Hedgehog-Gli. Sebbene il ruolo del segnale di Hedgehog (Hh) nei processi di embriogenesi e tumorigenesi sia ben noto, i meccanismi molecolari che ne sottendono la regolazione sono ancora ad oggi non definiti. Dati di letteratura riportano che processi proteolitici ubiquitina-dipendente rappresentano un evento cruciale per il controllo della via di Hh. Nel nostro laboratorio sono stati identificati due nuovi meccanismi di degradazione ubiquitina-dipendente coinvolti nella regolazione della proteina Gli1, il principale effettore del signaling di Hh: i) un meccanismo di degradazione promosso dalla proteina “adaptor” Numb e mediato dalla E3-ligasi Itch, appartenente alla famiglia delle HECT-E3 ubiquitin ligasi; ii) un meccanismo di degradazione indotto da una nuova E3-ligasi, REN/Cul3, da noi identificata, appartenente alla famiglia delle RING E3-ligasi. Dati precedentemente pubblicati dal nostro gruppo avevano dimostrato che una riduzione dei livelli di ubiquitinazione di Gli1, con conseguente accumulo, avvengono nel medulloblastoma a causa della perdita di Numb, una proteina coinvolta nella determinazione del destino cellulare, nel self-renewal e nel differenziamento (Di Marcotullio et al., 2006; Gulino et al., 2010). Inoltre era stato dimostrato come l’ubiquitinazione e la degradazione di Gli1 indotta da Numb fosse mediata dall’E3 ligasi Itch (Di Marcotullio et al., 2006). Sebbene, il ruolo dell’asse Gli/Numb/Itch nello sviluppo del medulloblastoma fosse stato ben sviluppato, i meccanismi molecolari coinvolti nella regolazione dell’attività di queste proteine non erano stati chiariti. Nella prima parte del mio lavoro di tesi ci siamo occupati di approfondire i meccanismi alla base dell’interazione tra Numb, Itch e Gli1 e di evidenziarne il significato funzionale. Numb interagisce con la regione centrale di Itch, contenente i domini WW, in particolare con il secondo dominio WW (WW2). Domini WW sono comunemente utilizzati per il legame con i diversi substrati di Itch, ed infatti abbiamo anche scoperto che Gli1 interagisce con la medesima regione. Tramite esperimenti di legame, sia in vivo che in vitro, abbiamo dimostrato che Numb ha la funzione sia di attivare Itch che di reclutare Gli1. Itch si trova infatti in una conformazione inattiva auto-inibitoria, in cui il ripiegamento del dominio catalitico HECT (C-terminale) in corrispondenza della regione dei WW (N-terminale), ne inibisce la sua attività catalitica. Il legame di Numb destabilizza l’interazione HECT-WW promuovendo l’apertura della struttura e portando quindi ad una conformazione attiva. Ciò favorisce l’entrata di Gli1 nel complesso e la sua successiva ubiquitinazione. A tal proposito, abbiamo dimostrato che Itch è in grado di legare direttamente Gli1 e che tale legame avviene tra i domini WW di Itch e i WW-binding sites PPXY e la S1060P, presenti nella regione C-terminale di Gli1. Importante, la proteina Gli1 mutata in questi siti non è soggetta alla proteolisi indotta da Itch e presenta maggiori proprietà oncogeniche. La seconda parte del lavoro di tesi è stata finalizzata all’analisi dei meccanismi molecolari che regolano l’attività di RENKCTD11/Cul3 ed alla loro alterazione nel medulloblastoma. In un lavoro precedentemente pubblicato, avevamo identificato RENKCTD11 come un oncosoppressore, localizzato sul cromosoma 17p e capace di antagonizzare l’attività di Hh. Sebbene fosse stata dimostrata la capacità di RENKCTD11 di inibire la funzione trascrizionale di Gli1, i meccanismi responsabili di questo processo non erano stati chiariti. Il fatto che REN possiede un dominio BTB/POZ (coinvolto nell’interazione con la Cullina3), responsabile del suo effetto sulla crescita e differenziamento dei progenitori neuronali e che uno dei meccanismi di ubiquitinazione di Gli1, vede il coinvolgimento del complesso HIB-SPOP/Cul3, ci ha fatto ipotizzare che RENKCTD11 fosse in grado di interagire con Cul3 e regolare la stabilità di proteine del signaling di Hh. Tramite esperimenti di co-IP e saggi di ubiquitinazione in vitro ed in vivo, abbiamo mostrato che RENKCTD11, attraverso un legame diretto con il dominio BTB/POZ, forma un complesso con Cul3 e svolge azione ubiquitin-ligasica. In particolare, abbiamo dimostrato che RENKCTD11 è capace di indurre ubiquitinazione e degradazione di HDAC1, una deacetilasi recentemente identificata nel nostro laboratorio come un potente attivatore del signaling di Hh e altamente espressa nei medulloblastomi. L’espressione ectopica di RENKCTD11, in linee cellulari di medulloblastoma, determinava una riduzione dei livelli di HDAC1, portando ad inibizione dell’attività di Gli1 e ad arresto della proliferazione. I risultati ottenuti da questa ricerca svelano la funzione di RENKCTD11 come una nuova Cul3-E3 ligasi ed il meccanismo attraverso il quale RENKCTD11, regolando negativamente HDAC1, inibisce il signaling di Hh. Queste evidenze sperimentali identificano nuovi meccanismi di regolazione dell’attività di Gli1 e forniscono una solida ragione per indagare sull'ipotesi che le proteine, Numb, Itch e RENKCTD11, sono coinvolte nello sviluppo del medulloblastoma e possono rappresentare bersagli per nuove strategie terapeutiche

«Ovunque sono, / io sono ciò che manca». Per una tragedia dell’assenza tra Tacito e Anagoor

Is it possible to construct a work of art on absence? Anagoor’s performance on the battle of  Teutoburg Forest succeeds. Absence builds performance’s modes of expression, without any help of objects or scenography. Absence determines the theme, the legions disappeared in the deadly ambush of the Battle. Other voices able to express the absence’s strength take turns during the performance: poetic voices able to create a personal dialogue with the dead , the ancestors, who are par excellence absent, grafted on Tacitus’ text to create many nuances of absence. Absence is mourning, sadness for differences, for insurmountable boundaries. But also absence as hope, because art is able to learn to speak any silence. È possibile costruire un’opera d’arte sull’assenza? La performance di Anagoor dedicata alla battaglia di Teutoburgo, Germania. Römischer Komplex, riesce nell’intento. L’assenza costruisce le modalità espressive della performance, che rinuncia a qualsiasi aiuto di scenografia o di oggetti scenici  per comporsi in una nudità evocativa. L’assenza determina l’impalpabilità del tema, le legioni svanite nell’agguato mortale delle quali solo le tracce vengono, anni dopo, identificate dai commilitoni sconvolti. Ma altre voci capaci di esprimere tutta la forza dell’assenza, della perdita, si alternano nel lavoro: voci poetiche che a loro volta hanno tentato un personale dialogo con gli assenti per eccellenza, i defunti, gli antenati (Antonella Anedda, Frank Bidart, Durs Grunbein), innestate sulla spina dorsale del testo di Tacito per una tastiera di sfumature che è la chiave del lavoro. Perdita come lutto, come irrimediabile tristezza per diversità immedicabili, per confini non superabili. Ma anche assenza come speranza, animata dalla traditio lampadis dell’arte che attraverso l’evocazione sa far parlare qualsiasi silenzio.   &nbsp

Optimal design of the ideal grounded tuned mass damper inerter for comfort performances improvement in footbridges with practical implementation considerations

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Modeling Power Flow in a Hoist Motor of a Rubber-Tired Gantry Crane

A method for calculating the power demand of the hoist motor in rubber-tired gantry (RTG) cranes with nonparallel cables has been developed to measure the energy consumption in a typical lift cycle. From measurements taken at the Port of Felixstowe, it has been observed that the peculiar geometrical characteristics of the hoisting mechanism cause the power demand to increase with the container height in constant rotor speed conditions. The change in the angle of the hoisting ropes causes an increase in torque load and power consumption. By using information extracted from the crane's geometry, it has been possible to calculate the potential energy increase given the weight and vertical position of the container. The load torque on the hoist motor and the vertical speed of the mass have also been calculated, allowing for the modeling of the hoist motor power consumption when lifting containers with constant rotational speed. The proposed model has been compared to a constant power demand approximation, showing a higher accuracy for masses below 40 t

Vibration control of steel liquid storage tanks equipped with Inerter-based isolation systems

Base isolation represents a very widely used strategy to mitigate the effects of earthquake excitation on structures. However, it can induce high displacements between the isolation layer and the ground, which may cause serious damage, and even heavy and dangerous consequences in case of industrial components. Among them, big steel tanks for storage of petroleum or other chemical products, should be considered very carefully. Moreover, isolation technique doesn’t seem to be effective in the control of the sloshing modes, due to the length of their periods of vibration. This fact can imply severe negative effects on the free surface of the storage tank, where the sloshing wave can exceed the upper limit of the tank, overtopping it, or inducing breaking on the floating roof. Moving from the results available in the Literature, in which the introduction in civil applications of a two terminal device, named inerter, able to generate an inertial mass much greater than its gravitational mass, is proposed; the force produced by the inerter is proportional to the difference of acceleration between its terminals. This work concerns the evaluation, through numerical models, of the seismic performance of a passive base isolation system involving a ground inerter system, called IBIS in the following, connecting the isolation layer of a steel liquid storage tank to the ground. The model considered in the numerical analysis consists in a reduced 2DOF linear system. The first degree of freedom is represented by the first sloshing mode; the second is relative to the base isolation system, whose mass includes the basement, the tank and the impulsive component of liquid mass. The aim is to gain a reduction of the response in terms both of isolation layer displacement and of sloshing height. The effectiveness of the control strategy proposed has been evaluated considering both a random white noise process and earthquakes (near-fault and far-field) as base input, achieving strong reduction of the response, in terms of sloshing height and isolation displacement

The Gamelan in the Catholic Liturgy in Yogyakarta

This paper is a brief overview of the use of the gamelan together with the polyphonic choir in the Roman rite of Holy Mass. Through the examination ofrepertoires, interviews and active participation in rehearsals and Masses, thiswork illustrates the types of compositions of liturgical music for gamelan aswell as the way these compositions are used. Particular attention is addressedto some key-concepts of traditional gamelan music, such as gending, benthuk,laras, pathet, garap. It will be apparent that these concepts are adapted, firstlyto integrate the gamelan with a vocal element, the choir (which is based on awestern tradition) and secondly, to meet the needs of the rite of Holy Mass.Although indirectly, this paper also represents a paradigm of “Inculturation”,which describes a process distinct from “Enculturation”. The term“Inculturation” must be intended as “the incarnation of the Gospel in nativecultures and also the introduction of these cultures into the life of the Church”,so defined by the Pope John Paul II in the encyclical Slavorum Apostoli, 2ndJune 1985, VI-21. Instead, with the term “Enculturation” we intend the processby which an individual learns the traditional content of a culture andassimilates its practices and values. Thus, the two words represent twodifferent processes of assimilation of culture

Optimal tuning and assessment of inertial dampers with grounded inerter for vibration control of seismically excited base-isolated systems

In this paper, the concept of an ideal grounded linear inerter, endowing supplemental inertia to passive linear tuned mass-dampers (TMDs) through its inertance property without increasing the TMD mass, is considered to reduce lateral displacement demands in base isolated structural systems (BISs). Optimal tuned mass-damper-inerter (TMDI) design parameters are numerically determined to maximize energy dissipation by the TMDI under stationary white noise support excitation. Performance of these optimally designed TMDI-equipped BISs is assessed for stationary white and colored noise excitations as well as for four recorded earthquake acceleration ground motions (GMs) with different non-stationary frequency content. It is found that for fixed mass ratio the inclusion of the grounded inerter reduces significantly secondary mass displacement and stroke for all considered excitations while it improves appreciably BIS displacement demands except for the particular case of a near-fault accelerogram characterized by early arrival of a high-energy low-frequency pulse as captured in its wavelet spectrogram. More importantly, it leads further to reductions to BIS acceleration demands with the exception of colored noise excitation for which an insignificant increase is noted. The positive effects of the inerter saturate with increasing inertance and BIS damping ratio demonstrating that small inertance values are more effective in vibration suppression of BISs with low inherent damping. Overall, it is recommended to combine low damping isolation layers with large inertance and low secondary mass TMDIs

combinatorial principle in the use of drum kendhang formulae in gamelan music of yogyakarta from prescriptive models to the interpretation of a composition the case of kendhang pinatut

In this paper, I address the question to the use of drums (kendhang) in the traditional Gamelan music of Yogyakarta, by presenting some prescriptive models (or formulas). I illustrate how, the use of different prescriptive models in a composition follow what I labeled as "Combinatorial Principle". In order to describe the essential elements of this principle, I will analyze the modalities of interaction between a very flexible drum formula (known as pinatut) and three other prescriptive models for drum within some exemplary pieces of traditional Gamelan music. The concept of combinatorial principle illustrated in these pages, on the one hand explains the way of interaction between the drum's rhythmic formulas and their capacity to influence the choices made by the entire orchestra during a performance; on the other hand, through this principle we are able to trace a path that attempts to understand the "deep structures" that are the basics of making music in Gamelan tout court. Through the perspective of the combinatorial principle it is possible to analyze the prescriptive models and techniques of many other instruments of the Gamelan of central Java