Seismic Response of a Platform-Frame System with Steel Columns

Timber platform-frame shear walls are characterized by high ductility and diffuse energy dissipation but limited in-plane shear resistance. A novel lightweight constructive system composed of steel columns braced with oriented strand board (OSB) panels was conceived and tested. Preliminary laboratory tests were performed to study the OSB-to-column connections with self-drilling screws. Then, the seismic response of a shear wall was determined performing a quasi-static cyclic-loading test of a full-scale specimen. Results presented in this work in terms of force-displacement capacity show that this system confers to shear walls high in-plane strength and stiffness with good ductility and dissipative capacity. Therefore, the incorporation of steel columns within OSB bracing panels results in a strong and stiff platform-frame system with high potential for low- and medium-rise buildings in seismic-prone areas

Registro del comportamiento de corrientes con derrubios en el torrente Moscardo (Alpes italianos)

[ES] Los datos sobre corrientes con derrubios recogidos en cuencas monitoreadas tienen gran importancia para mejorar la comprensión de estos peligrosos fenómenos, a fin de desarrollar medidas de mitigación (sistemas de alerta temprana, obras de ordenación). El torrente Moscardo, un pequeño curso de los Alpes Orientales (área de la cuenca: 4.1 km2) ha sido instrumentado para el monitoreo de las corrientes con derrubios, registrándose catorce eventos desde 1990 hasta 1997. La instrumentación de monitoreo instalada en la cuenca incluye pluviógrafos, sensores ultrasónicos, sensores sísmicos y una telecámara, que permiten medir la lluvia, el nivel del flujo y las vibraciones causadas por el paso de la corriente con derrubios. Otras importantes variables, como la velocidad media del frente del flujo, el caudal máximo y el volumen, se estiman elaborando los datos medidos. Las imágenes registradas por la telecámara han sido utilizadas para interpretar las diferentes fases que se producen en una creLas investigaciones sobre las corrientes con derrubios en el torrente Moscardo se desarrollan en el contexto del proyecto nacional GNDCI – (U.O. 1.29 y 2.63).Marchi, L. (2004). Registro del comportamiento de corrientes con derrubios en el torrente Moscardo (Alpes italianos). Ingeniería del agua. 11(3):275-280. https://doi.org/10.4995/ia.2004.2536OJS275280113Arattano, M. (1999) On the use of seismic detectors as monitoring and warning systems for debris flows. Natural Hazards 20 (2-3), 197-213.Arattano, M., Grattoni, P. (2000) Using a fixed video camera to measure debris-flow surface velocity. In: Wieczorek, G., Naeser, N. (Eds.), Proceedings, Second International Conference on Debris-flow Hazard Mitigation: Mechanics, Prediction, and Assessment. A.A. Balkema, Rotterdam, 273-281.Bovis, M.J. and Jakob, M. (1999) The role of debris supply conditions in predicting debris flow activity. Earth Surface Landforms and Processes, 24 (11), 1039-1054.Coussot, Ph., Laigle, D., Arattano, M., Deganutti, A.M., Marchi, L. (1998) Direct determination of rheological characteristics of debris flow. Journal of Hydraulic Engineering ASCE 124(8), 865-868.Deganutti, A.M., Marchi, L., Arattano, M. (2000) Rainfall and debris flow occurrence in the Moscardo basin (Italian Alps). In: Wieczorek, G., Naeser, N. (Eds.), Proceedings, Second International Conference on Debris-flow Hazard Mitigation: Mechanics, Prediction, and Assessment. A.A. Balkema, Rotterdam, 67-72.Hürlimann, M., Rickenmann, D., Graf, C. (2002) Field and monitoring data of debris-flow events in the Swiss Alps. Canadian Geotechnical Journal, 40 (1), 161-175.Marchi, L., Arattano, M., Deganutti, A.M. (2002) Ten years of debris-flow monitoring in the Moscardo Torrent (Italian Alps). Geomorphology, 46 (1/2), 1-17.Mizuyama T., Kobashi S. & Ou G. (1992) Prediction of debris flow peak discharge. Interational Symposium Interpraevent 1992 - Bern, vol. 4, 99-108.Moscariello, A., Deganutti, A.M. (2000) Sedimentary and hydrologic processes of a debris-flow dominated alluvial fan - Moscardo Fan, Italy. In: Wieczorek, G., Naeser, N. (Eds.), Proceedings, Second International Conference on Debris-flow Hazard Mitigation: Mechanics, Prediction, and Assessment. A.A. Balkema, Rotterdam, 301-310.Okuda, S., Suwa, H., Okunishi, K., Yokoyama, K., Nakano, M. (1980) Observations on the motion of a debris flow and its geomorphological effects. Zeitschrift für Geomorphologie N.F., Suppl. Bd. 35, 142-163.Pierson, T.C. (1986) Flow behavior of channelized debris flows, Mount St. Helens, Washington. In: Abrahms, A.D., (Ed.), Hillslope Processes. Allen and Unwin, Boston, 269-296.Suwa, H., Yamakoshi, T., Sato, K. (2000) Relationship between debris-flow discharge and ground vibration. In: Wieczorek, G., Naeser, N. (Eds.), Proceedings, Second International Conference on Debris-flow Hazard Mitigation: Mechanics, Prediction, and Assessment. A.A. Balkema, Rotterdam, 311-318.Tecca, P.R., Galgaro, A., Genevois, R., Deganutti, A.M. (2003) Development of a remotely controlled debris flow monitoring system in the Dolomites (Acquabona, Italy). Hydrological Processes, 17, 1771-1784.Zhang, S. (1993) A comprehensive approach to the observation and prevention of debris flows in China. Natural Hazards 7(1), 1-23

Three-dimensional geometric morphometric analysis of the first metacarpal distal articular surface in humans, great apes and fossil hominins

Understanding the manual abilities of fossil hominins has been a focus of palaeoanthropological research for decades. Of interest are the morphological characteristics of the thumb due to its fundamental role in manipulation, particularly that of the trapeziometacarpal joint. Considerably less attention has been given to the thumb metacarpophalangeal (MCP) joint, which plays a role in stabilizing the thumb during forceful grasps and precision pinching. In this study we use a three-dimensional geometric morphometric approach to quantify the shape of the first metacarpal head in extant hominids (Homo, Pan, Gorilla and Pongo) and six fossil hominin species (Homo neanderthalensis Tabun C1 and La Chappelle-aux-Saints, Homo naledi U.W. 101-1282, Australopithecus sediba MH2, Paranthropus robustus/early Homo SK84, Australopithecus africanus StW 418, Australopithecus afarensis A.L. 333w-39), with the aims of identifying shapes that may be correlated with human-like forceful opposition and determining if similar morphologies are present in fossil hominins. Results show that humans differ from extant great apes by having a distally flatter articular surface, larger epicondyle surface area, and a larger radial palmar condyle. We suggest that this suite of features is correlated with a lower range of motion at the MCP joint, which would enhance the thumbs ability to resist the elevated loads associated with the forceful precision grips typical of humans. Great ape genera are each differentiated by distinctive morphological features, each of which is consistently correlated with the predicted biomechanical demands of their particular locomotor and/or manipulatory habits. Neanderthals and U.W. 101-1282 fall within the modern human range of variation, StW 418, SK 84 and U.W. 88-119 fall in between humans and great apes, and A.L. 333w-39 falls within Pan variation. These results agree with those of traditional linear analyses while providing a more comprehensive quantitative basis from which to interpret the hand functional morphology of extinct hominins

A quasi-complete mechanical model for a double torsion pendulum

We present a dynamical model for the double torsion pendulum nicknamed PETER, where one torsion pendulum hangs in cascade, but off-axis, from the other. The dynamics of interest in these devices lies around the torsional resonance, that is at very low frequencies (mHz). However, we find that, in order to properly describe the forced motion of the pendulums, also other modes must be considered, namely swinging and bouncing oscillations of the two suspended masses, that resonate at higher frequencies (Hz). Although the system has obviously 6+6 Degrees of Freedom, we find that 8 are sufficient for an accurate description of the observed motion. This model produces reliable estimates of the response to generic external disturbances and actuating forces or torques. In particular, we compute the effect of seismic floor motion (tilt noise) on the low frequency part of the signal spectra and show that it properly accounts for most of the measured low frequency noise.Comment: 15 pages, 6 figure

Statistical inferential techniques for approaching forest mapping. A review of methods

The increasing availability of remote sensing data at no or low costs can be used as ancillary data in order to spatialize and improve the estimation of forest attributes and without increasing the sampling effort and costs. In this review paper, a description of the main statistical inferential techniques for approaching forest mapping is proposed. This article reviews the most used forest mapping methods based on the sole spatial information as well as techniques exploiting auxiliary information from remotely sensed data. The advantages and drawbacks of each method have been described on the basis of several factors, such as the aims of the investigation and the area under examination. Two main groups were here discussed with model-based methods on one side and model-assisted methods on the other, moving the attention from the model used to interpolate surfaces to the sampling scheme. Model-based methods include kriging, locally weighted regression, K-NN, decision trees and neural networks, while the inverse distance weighting interpolator is presented in the model-assisted group.Reliable and up-to-date information on forest characteristics are mandatory tools for any decisional process. The main input data of such systems are wall-to-wall maps depicting the spatial structures of forests and additional elements. Actually, if the original aim of forest inventories was to estimate harvestable timber amounts, a general interest towards multipurpose surveys is mandatory. Such information must deal with increased costs and more time-consuming procedures.

Ghrelin plasma levels after 1 year of ketogenic diet in children with refractory epilepsy

The ketogenic diet (KD) is a high-fat, low carbohydrate nutritional treatment adopted in several countries for refractory epilepsy. However, the use of KD is limited by adverse events including growth retardation. In a previous investigation, we demonstrated that ghrelin is reduced in children maintained on KD for 3 months. As ghrelin regulates growth hormone (GH) secretion, it can be hypothesized that growth retardation depends on the reduced ghrelin availability. To assess this hypothesis, in this study we evaluate ghrelin and growth during 1 year of KD. We examined a small cohort of 6 children (2 males and 4 females, age range 3\u201310.4 years) affected by refractory epilepsy, who received the KD as add-on treatment. All patients were on drug polytherapy. Endpoints of the study were: (i) ghrelin plasma levels at 0, 15, 30, 90, and 365 days from KD onset, (ii) growth, and (iii) seizure control by ketogenesis. Ghrelin levels were 1253 and 1247% of basal levels, respectively, at 90 and 365 days (P < 0.05 for both). Mean height index z scores were reduced, but not significantly, by comparing basal values with those at the end of observation. Instead, body mass index z scores slightly increased. Ketosis induced by the KD was within 2\u20135 mmol/L and satisfactorily reduced the seizure frequency (>50%) in all patients. We show that ghrelin plasma levels are consistently reduced in children with refractory epilepsy and maintained on the KD. This change was associated with low growth indexes in the majority of patients