1,337 research outputs found
Predicting the Pressure Dependence of Elastic Velocities of Dry Granular Assemblies Using a Modified GCT Model
No full textEvaluating abnormal pore pressure (overpressure zones) is a major safety issue in well drilling for oil and gas exploration. Nevertheless, presently, the problem of assessing the dependence of elastic moduli with pressure in unconsolidated media is still an open question even for the simple case of dry materials and packing of identical spherical grains. This is because the effective medium theory (EMT) based on the Hertz-Mindlin contact theory fails to predict the measured trend in laboratory data. To overcome this issue, we test a modified grain contact theory (GCT) model that fits elastic moduli with pressure proposed by Saul et al. (2013). We optimized this method by allowing a non linear relation between the calibration parameter and porosity and a simpler relation between pressure and porosity. We show that this model can predict the Vp and Vs pressure trends using published laboratory datasets by performing a blind test on Santa Cruz agglomerate samples
"Residenze a patio Fornace del Bersaglio, Faenza RA"
No full textProgetto (Architettura Ingegneria) di recupero di area industriale dismessa con funzione di Fornace di Laterizi del primi del novecento costruita all'interno di una cava di argilla. Il progetto si propone come modello sotto vari aspetti. La riattivazione di tutta l'area industriale dismessa con l'inserimento di funzioni pubbliche culturali mescolate a nuove residenze e parchi pubblici. Una proposta sociale per un abitare collettivo in campagna contemporaneo. Una trasformazione con un forte carattere di sostenibilità ambientale. In ultimo, si tratta di un progetto sperimentale di una trasformazione a costi contenuti inserita nell'ambito del social housing. La scelta di sviluppare la tipologia della casa a patio mediterranea va nella direzione di costruire un piccolo borgo apparentemente denso, costituito da piccole residenze a patio con doppio giardino. Un condominio orizzontale sotto un bosco di alberi che si configura come il giardino della vecchia Fornace recuperata a spazi pubblici ad uso culturale. Nella parte residenziale, le tipologie sono tutte a patio, ma con leggere differenze, morfologiche e dimensionali allo scopo di renderle peculiari e adatti a diverse tipologie di nuclei familiari o altri usi. La sostenibilità ambientale è riferita sia alle tecnologie costruttive, che utilizzano materiali naturali: laterizio, strutture e solai in legno, pavimentazioni in ghiaino pressato e legno e i tetti verdi, sia allo studio della filiera del processo costruttivo che utilizza le risorse locali artigianali, riducendo al minimo l'uso del prodotto industriale assemblato. Particolare attenzione viene posta nella proposta di abitare in campagna, indagando nella relazione fra decoro dello spazio pubblico e privacy dello spazio privato
Performance and Stability Analysis of Echo Cancellers Based on Training Sequences
No full textWe analyze a two-stage echo cancellation technique
for on-channel repeaters (OCRs) based on the reconstruction
of the coupling channel impulse response via digital filtering.
The estimation of the coupling channel between the transmitting
and the receiving antennas is achieved through the injection
in the repeated signal of locally generated low-power pseudonoise
sequences or trains of short pulses. The analytical model
developed in this paper permits the investigation of some important
performance figures, such as the mean rejection ratio, the
echo suppression and the echo suppression at nominal position.
In addition, a new analytical framework dealing with canceller
stability issues, arising due to the non perfect echo cancellation,
is derived. Specifically, an upper bound on the probability
of instability of the canceller is provided. As shown in the
numerical results, this framework permits the identification of
the main OCR design guidelines. Finally, we will validate our
analytical models by showing their accordance with the experimental
measurements realized with the OCR prototypes we
developed
Parcoverde housing complex
No full textL’intervento di progettazione urbana Parco Verde di Faenza si inserisce all’interno di un sistema di infrastrutture verdi molto ampio e ricco di servizi. La parte dedicata alla residenza, circa 200 appartamenti di diverse dimensioni, è sviluppata all’interno del social housing e propone una morfologia urbana compatta con la stessa densità del centro storico, ma immersa nel verde. L’area residenziale è car free e lo spazio pubblico è completamente pedonalizzato. Gli edifici sono semplici, ma hanno alcuni elementi propositivi che ne definiscono il carattere. La forma strutturale degli edifici a telaio è avvolta in una cortina muraria poligonale che disegna la dinamicità dello spazio pubblico. Il rapporto pubblico privato è filtrato da un uso massiccio di ampie logge su cui affacciano le aperture private. Le bucature delle logge si relazionano sullo spazio privato con una composizione su una facciata libera assicurando così una maggiore privacy alle residenze. L’interno delle residenze è strutturato in modo da impostare una vita intorno alla loggia. La volontà di proporre un intervento a basso costo ha portato a scegliere tecnologie costruttive tradizionali. Il carattere innovativo dell’intervento ha avuto riscontri in pubblicazioni e premi. Gabriele Lelli (capogruppo) risulta finalista con il social housing "Parcoverde housing complex" al Premio Internazionale "Ugo Rivolta" 2015 – la quinta edizione del premio, volta a divulgare i migliori progetti di edilizia sociale realizzati in ambito europeo negli ultimi cinque anni. Il Premio è un'iniziativa della Fondazione dell'Ordine degli Architetti PPC della Provincia di Milano insieme ai partner scientifici: Unità di ricerca '2C Casa e Città - Dipartimento di Architettura e Studi Urbani - Politecnico di Milano', con una Giuria Internazionale; è un riferimento internazionale per la ricerca e il dibattito sulla qualità complessiva dell'ambiente costruito e la sostenibilità del progetto architettonico
Correction to: When terminology hinders research: the colloquialisms of transitions of control in automated driving (Cognition, Technology & Work, (2022), 10.1007/s10111-022-00705-3)
No full textIn the original article, author affiliation published with error. The correct affiliations are: Davide Maggi—Institute for Transport Studies, Leeds, UK. Richard Romano—Institute for Transport Studies, Leeds, UK. Oliver Carsten—Institute for Transport Studies, Leeds, UK. Joost C. F. De Winter—Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands. The original article has been corrected.Human-Robot Interactio
Preoperative valgus deformity has twice the risk of failure as compared to varus deformity after total knee arthroplasty
No full textPurpose: The aim of this study was to assess whether preoperative valgus or varus deformity affected survivorship after total knee arthroplasty (TKA) and to quantify the risk factors for implant failure in a registry-based population. Methods: The Emilia-Romagna Registry of Prosthetic Orthopedic Implants was examined regarding TKAs performed on patients with a preoperative diagnosis of valgus or varus deformity. Demographics, implant characteristic and survivorships were investigated and compared. A total of 2327 TKA procedures performed from 2000 to 2016 were included in the study. Six hundred and forty primary TKAs with a diagnosis of valgus deformity were evaluated with a median follow-up of 3.3 years; 1687 primary TKAs with a diagnosis of varus deformity were evaluated with a median follow-up of 2.5 years. Results: Bi-compartmental, cemented posterior stabilised fixed-bearing implants were preferred. For both diagnoses, the implant survivorship rate was greater than 98% in the first year. However, the survival curve of the TKAs implanted for valgus deformity showed a greater slope in the first 3 years as compared to the survival curve of those implanted for varus deformity. Valgus deformity had a 2.1-fold higher risk for revision as compared with varus deformity. Infection was a major cause of implant failure in TKAs for varus deformity, 9/24 (37.5%), while its incidence was lower for valgus deformity, 1/21 (4.8%). Conclusions: Preoperative valgus alignment showed a twofold risk of failure as compared to varus alignment after TKA. This should be considered in daily practice, and surgeons are called on to pay more attention when performing TKAs on such patients. Prospective randomised controlled trials are, therefore, necessary to better understand the role of preoperative coronal knee deformity in implant failure. Level of evidence: Prognostic study, level III
An upper bound on the probability of instability of a DVB-T/H repeater with a digital echo canceller
No full textThe architecture of a digital On-Channel Repeater
(OCR) for DVB-T/H signals is described in this paper. The
presence of a coupling channel between the transmitting and the
receiving antennas gives origin to one or more echoes, having
detrimental effects on the quality of the repeated signal and
critically affecting the overall system stability. A low-complexity
echo canceller unit is then proposed, performing a coupling
channel estimation based on the local transmission of lowpower
training signals. In particular, in this paper we focus
on the stability issues which arise due to the non perfect echo
cancellation. An upper bound on the probability of instability
of the system is analytically found, providing useful guidelines
for conservative OCR design, and some performance figures
concerning different propagation scenarios are provided
Admiel Kosman, Siamo giunti a Dio
No full textInternational audienceSix poems from Israeli poet Admiel Kosman translated from the Hebrew into Italian. Selection of poems, presentation of the author, translation and notes by Davide Mano
Admiel Kosman, Siamo giunti a Dio
No full textInternational audienceSix poems from Israeli poet Admiel Kosman translated from the Hebrew into Italian. Selection of poems, presentation of the author, translation and notes by Davide Mano
Starchitecture: Scenes, Actors and Spectacles in Contemporary Cities
No full textHow and why do spectacular buildings get commissioned and procured? What are their visible urban effects? What can urban planners, architects, and policymakers learn in order to engage in more successful citymaking?
In recent years, media and critical attention has been lavished on famous architects, and the contributions of their designs to the branding of cities. The post-“Bilbao effect” global landscape is one where cities compete for the highest-profile skyscrapers, cultural projects, and high-profile developments designed by star architects whom even casual readers know by first name: Frank Gehry, Bjarke Ingels, Jean Nouvel, Zaha Hadid, Norman Foster, Rem Koolhaas. Far less is known about the decision-making processes behind these projects and their subsequent urban effects.
A unique combination of urban studies and photography, Starchitecture investigates projects designed by star architects in cities including Paris, New York, Abu Dhabi, Bilbao, and the architectural microcosm of the Vitra campus in Weil am Rhein, Germany. Author Davide Ponzini and photographer Michele Nastasi seek to explain and critique a growing global condition by revealing how starchitecture has been and continues to be deployed in cities around the world. The arguments they raise are vital to understanding the urban landscapes of today, and tomorrow
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