Attività svolta nell’ambito delle verifiche di agibilità nella provincia de L’Aquila e considerazioni sulle registrazioni accelerometriche del 06/04/2009

Nel presente articolo si illustra l’attività svolta dagli Autori nell’ambito delle verifiche di agibilità. In N. 5 - 2009 13 particolare tra tutti gli edifici esaminati ne sono stati selezionati tre, uno per tipologia strutturale (c.a., c.a.p. e muratura), ritenuti più rappresentativi. Si fornisce poi un breve resoconto della situazione riscontrata a Castelnuovo, una delle Località maggiormente colpite. Vengono inoltre date delle indicazioni preliminari sulla risposta del costruito, in base a quanto osservato sul campo ed in base ad alcune valutazioni che è già possibile fare sulle registrazioni accelerometriche del 06/04/2009. L’evento sismico in oggetto è stato inquadrato nella storia sismica del territorio de L’Aquila e messo in relazione con i terremoti più significativi verificatisi in Italia negli ultimi decenni: Friuli 1976, Irpinia 1980, Umbria– Marche 1997, Molise 2002. Infine si è proceduto ad un confronto con l’azione sismica prevista dall’attuale Normativa (D.M. LL.PP. del 14/01/2008 [3] e relativa C.M. LL.PP. N. 617 del 02/02/2009 [4]), confronto dal quale non può prescindere una lettura critica del grado di danneggiamento prodotto sulle diverse tipologie strutturali

Terahertz rectifyier for integrated image detector

We present a new CMOS compatible direct conversion terahertz detector operating at room temperature. The rectenna consists in a truncated conical helix extruded from a planar spiral and connected to a nanometric metallic whisker at one of its edges. The whisker reaches the semiconductor substrate that constitutes the antenna ground plane. The rectifying device can be obtained introducing some simple modifications of the charge storage well in conventional CMOS APS devices, making the proposed solution easy to integrate with existing imaging systems. No need of scaling toward very scaled and costly technological node is required, since the CMOS only provides the necessary integrated readout electronics. On-wafer measurements of RF characteristics of the designed rectifying junction are reported and discussed

CMOS-Compatible Room-Temperature Rectifier Toward Terahertz Radiation Detection

In this paper, we present a new rectifying device, compatible with the technology of CMOS image sensors, suitable for implementing a direct-conversion detector operating at room temperature for operation at up to terahertz frequencies. The rectifying device can be obtained by introducing some simple modifications of the charge-storage well in conventional CMOS integrated circuits, making the proposed solution easy to integrate with the existing imaging systems. The rectifying device is combined with the different elements of the detector, composed of a 3D high-performance antenna and a charge-storage well. In particular, its position just below the edge of the 3D antenna takes maximum advantage of the high electric field concentrated by the antenna itself. In addition, the proposed structure ensures the integrity of the charge-storage well of the detector. In the structure, it is not necessary to use very scaled and costly technological nodes, since the CMOS transistor only provides the necessary integrated readout electronics. On-wafer measurements of RF characteristics of the designed junction are reported and discussed. The overall performances of the entire detector in terms of noise equivalent power (NEP) are evaluated by combining low-frequency measurements of the rectifier with numerical simulations of the 3D antenna and the semiconductor structure at 1 THz, allowing prediction of the achievable NEP

Out-of-plane capacity of cladding panel-to-structure connections in one-story R/C precast structures

AbstractThe interaction between cladding panels and the main structure is a crucial point to assess the seismic response, and above all the structural safety, of RC precast industrial building. In the past, connections were often designed to allow construction tolerances and to accommodate both thermal and wind-induced displacements. The lack of specific details to allow relative in-plane displacements between cladding panels and the main structure often led to the participation of cladding panels in the structure seismic-resistant system with consequent connection failures. In the last decades, a lot of experimental tests were performed to investigate the in-plane performance of panel connections, and some design recommendations have been developed accordingly. In the out-of-plane direction, the connections were often considered to be infinitely rigid and not to suffer any damage by the seismic load. This work deals with the out-of-plane response of panel-to-structure connections for vertical panels typical of industrial and commercial precast buildings. Both standard hammer-head strap and new devices, called SismoSafe, were investigated. Tests were performed in the Structures and Materials Testing Laboratory of the Department of Civil and Environmental Engineering of Florence, where a specific setup was designed to perform cyclic and monotonic tests on the connection devices. Standard connections showed a rather limited resistance, while the innovative connections exhibited a high out-of-plane resistance. Numerical analyses were also performed on a case study building to evaluate the distribution of the out-of-plane demand on the connections

A setup for soft proton irradiation of X-ray detectors for future astronomical space missions

Protons that are trapped in the Earth's magnetic field are one of the main threats to astronomical X-ray observatories. Soft protons, in the range from tens of keV up to a few MeV, impinging on silicon X-ray detectors can lead to a significant degradation of the detector performance. Especially in low earth orbits an enhancement of the soft proton flux has been found. A setup to irradiate detectors with soft protons has been constructed at the Van-de-Graaff accelerator of the Physikalisches Institut of the University of T\"ubingen. Key advantages are a high flux uniformity over a large area, to enable irradiations of large detectors, and a monitoring system for the applied fluence, the beam uniformity, and the spectrum, that allows testing of detector prototypes in early development phases, when readout electronics are not yet available. Two irradiation campaigns have been performed so far with this setup. The irradiated detectors are silicon drift detectors, designated for the use on-board the LOFT space mission. This paper gives a description of the experimental setup and the associated monitoring system.Comment: 20 pages, 10 figures, 4 table

Numerical insights on ionic microgels: structure and swelling behaviour

Recent progress has been made in the numerical modelling of neutral microgel particles with a realistic, disordered structure. In this work we extend this approach to the case of co-polymerised microgels where a thermoresponsive polymer is mixed with acidic groups. We compare the cases where counterions directly interact with microgel charges or are modelled implicitly through a Debye-H\"uckel description. We do so by performing extensive numerical simulations of single microgels across the volume phase transition (VPT) varying the temperature and the fraction of charged monomers. We find that the presence of charges considerably alters the microgel structure, quantified by the monomer density profiles and by the form factors of the microgels, particularly close to the VPT. We observe significant deviations between the implicit and explicit models, with the latter comparing more favourably to available experiments. In particular, we observe a shift of the VPT temperature to larger values as the amount of charged monomers increases. We also find that below the VPT the microgel-counterion complex is almost neutral, while it develops a net charge above the VPT. Interestingly, under these conditions the collapsed microgel still retains a large amount of counterions inside its structure. Since these interesting features cannot be captured by the implicit model, our results show that it is crucial to explicitly include the counterions in order to realistically model ionic thermoresponsive microgels

Dark current spectroscopy of transition metals in CMOS image sensors

We have investigated the effects of deliberate heavymetals contamination on dark current and image defects in CMOS Image Sensors (CIS). Analysis of dark current in these imager dice has revealed different behaviors among most important 3d metals present in the process line. We have implanted directly in 3 Mega array pixels the following metals: Cr, V, Cu, Ni, Fe, Ti, Mo, W, Al and Zn. Analyzing the dark current "spectrum" as obtained for fixed integration periods of time by means of standard image-Testing equipment, these impurities can be identified and detected with a sensitivity of ∼ 109 traps/cm3 or higher