22 research outputs found
Herakleides Pontikos und die ps.-Plutarchische Schrift Peri Mousikes
No full textSi cerca di dimostrare che gli studiosi finora (seguendo Westphal) hanno attribuito troppe parti del trattatello ps.-plutarcheo "De musica" a Eraclide Pontico; a quest ́ ultimo l ́ ignoto autore ha attinto in realta ́ solo quello che dice di aver letto nell ́ iscrizione di Sicione.We try to show that up to now scholars (following Westphal) have attributed too many parts of the ps.-plutarcheo tract "De musica" to Eraclide Pontico; the unknown author drew from the latter only what he says he read in Sicyon's inscription
Imprese dell' Offitioso, accademico intronato /
No full textIncludes errata at end of both pts.Includes indexes.T.p. woodcuts of Medici arms (pt. 1), Gonzaga arms impaling Medici (pt. 2). Woodcut emblematic ill. Tail-pieces of printer's ornaments.Pt. 1 dated 1629. Pt. 2 has separate t.p. dated 1628, and is separately signed and paged.By Alcibiade Lucarini. See Praz.Praz, M. Studies in 17th-century imagery (2nd ed.)Mode of access: Internet.Armorial bookplate on front pastedown (lion's head erased and in chief a crowned eagle). Ownership inscription of Dominicus Portius.Binding: both pts. in 1 vol. cover in vellum, author & title written on spine, 2 pairs of new rawhide ties
Chemo-Resistive Gas Sensors Based on PbS Colloidal Quantum Dots
No full textIn this paper, we investigate the sensitivity and selectivity of lead sulphide colloidal quantum dots (CQDs) gas sensor. The benefits of CQDs, compared to commercial bulk sensor gas, are a large surface/volume ratio, a lower operating temperature, an easy deposition process and a precise control of dimensions to increase sensor sensitivity. The sensor is based on a chemo-resistive device with an active layer composed by PbS CQDs deposited on interdigitated metal contacts with a ligand exchange treatment. The sensor performance are validated on different gas pollutants (NO 2 , NO, CO 2 and CO) for increasing gas concentrations and times. The sensor shows high selectivity towards NO and NO 2 against CO and CO 2 at room temperature
Fabrication and Characterization of Capacitive Micromachined Ultrasonic Transducers Integrated on Ultra-thin and Flexible Substrates
No full textPolymer-based microfabrication approaches have been recently proposed as a low-cost alternative to traditional Capacitive Micromachined Ultrasonic Transducers (CMUT) fabrication methods. In most of the CMUT structures fabricated using such approaches, the electrodes passivation is achieved by a spin-coated polymer layer, with dielectric properties typically unsuitable to withstand the high in-cavity electrical fields. Moreover, typical layer thicknesses achievable by spin-coating bring to a significant increase of the effective gap height, inducing a very high collapse voltage and thus the need to use unpractically high operating voltages. In this paper, we investigate a process aimed at fabricating flexible CMUTs, potentially enabling high-performance, low-cost, curved, and ultra-miniaturized transducer configurations. In the proposed process, CMUT fabrication is carried out on an ultra-thin Polyimide substrate spun on a silicon wafer. The electrodes passivation is achieved by a thin SiO2 layer with excellent dielectric properties. A thin layer of SU-8 is used for the membrane fabrication and for sacrificial etch holes sealing. The devices are mechanically peeled-off from the wafer at the end of the process
Hydrological cycle over South and Southeast Asian river basins as simulated by PCMDI/CMIP3 experiments
No full textWe investigate how the climate models contributing to the PCMDI/CMIP3 dataset describe the hydrological cycle over four major South and Southeast Asian river basins (Indus, Ganges, Brahmaputra and Mekong) for the 20th, 21st (13 models) and 22nd (10 models) centuries. For the 20th century, some models do not seem to conserve water at the river basin scale up to a good degree of approximation. The simulated precipitation minus evaporation (P-E), total runoff (R) and precipitation (P) quantities are neither consistent with the observations nor among the models themselves. Most of the models underestimate P-E for all four river basins, which is mainly associated with the underestimation of precipitation. This is in agreement with the recent results on the biases of the representation of monsoonal dynamics by GCMs. Overall, a modest inter-model agreement is found only for the evaporation and inter-annual variability of P-E. For the 21st and 22nd centuries, models agree on the negative (positive) changes of P-E for the Indus basin (Ganges, Brahmaputra and Mekong basins). Most of the models foresee an increase in the inter-annual variability of P-E for the Ganges and Mekong basins, thus suggesting an increase in large low-frequency drywet events. Instead, no considerable future change in the inter-annual variability of P-E is found for the Indus and Brahmaputra basins © Author(s) 2013
Seasonality of the hydrological cycle in major South and Southeast Asian river basins as simulated by PCMDI/CMIP3 experiments
No full textIn this study, we investigate how PCMDI/CMIP3 general circulation models (GCMs) represent the seasonal properties of the hydrological cycle in four major South and Southeast Asian river basins (Indus, Ganges, Brahmaputra and Mekong). First, we examine the skill of the GCMs by analysing their performance in simulating the 20th century climate (1961-2000 period) using historical forcing (20c3m experiment), and then we analyse the projected changes for the corresponding 21st and 22nd century climates under the SRESA1B scenario. The CMIP3 GCMs show a varying degree of skill in simulating the basic characteristics of the monsoonal precipitation regimes of the Ganges, Brahmaputra and Mekong basins, while the representation of the hydrological cycle over the Indus Basin is poor in most cases, with a few GCMs not capturing the monsoonal signal at all. While the model outputs feature a remarkable spread for the monsoonal precipitation, a satisfactory representation of the western mid-latitude precipitation regime is instead observed. Similarly, most of the models exhibit a satisfactory agreement for the basin-integrated runoff in winter and spring, while their spread is large for the runoff during the monsoon season. For the future climate scenarios, most models foresee a decrease in the winter P - E over all four basins, while agreement is found on the decrease of the spring P - E over the Indus and Ganges basins only. Such decreases in P - E are mainly due to the decrease in precipitation associated with the western mid-latitude disturbances. Consequently, for the Indus and Ganges basins, the runoff drops during the spring season while it rises during the winter season. Such changes indicate a shift from rather glacial and nival to more pluvial runoff regimes, particularly for the Indus Basin. Furthermore, the rise in the projected runoff, along with the increase in precipitation during summer and autumn, indicates an intensification of the summer monsoon regime for all study basins. ©Author(s) 2014
Vertical and horizontal processes in the global atmosphere and the maximum entropy production conjecture
No full textThe objective of this paper is to reconsider the Maximum Entropy Production conjecture (MEP) in the context of a very simple two-dimensional zonal-vertical climate model able to represent the total material entropy production due at the same time to both horizontal and vertical heat fluxes. MEP is applied first to a simple four-box model of climate which accounts for both horizontal and vertical material heat fluxes. It is shown that, under condition of fixed insolation, a MEP solution is found with reasonably realistic temperature and heat fluxes, thus generalising results from independent two-box horizontal or vertical models. It is also shown that the meridional and the vertical entropy production terms are independently involved in the maximisation and thus MEP can be applied to each subsystem with fixed boundary conditions. We then extend the four-box model by increasing its resolution, and compare it with GCM output. A MEP solution is found which is fairly realistic as far as the horizontal large scale organisation of the climate is concerned whereas the vertical structure looks to be unrealistic and presents seriously unstable features. This study suggest that the thermal meridional structure of the atmosphere is predicted fairly well by MEP once the insolation is given but the vertical structure of the atmosphere cannot be predicted satisfactorily by MEP unless constraints are imposed to represent the determination of longwave absorption by water vapour and clouds as a function of the state of the climate. Furthermore an order-of-magnitude estimate of contributions to the material entropy production due to horizontal and vertical processes within the climate system is provided by using two different methods. In both cases we found that approximately 40mWm-2 K-1 of material entropy production is due to vertical heat transport and 5-7mWm-2 K-1 to horizontal heat transport. © Author(s) 2012
Fluorinated Agents Effects on Orthodontic Alloys: A Descriptive In Vitro Study
No full textFluoride-based mouthwashes and gels are preventive measures in countering demineralization and caries but, modifying environmental acidity, can reduce the wet corrosion resistance of orthodontic alloys. To evaluate chemical stability, in vitro experiments were conducted on stainless steel and nickel–titanium wires, weighed before and after immersion in household fluorinated mouthwashes and gels, measuring weight variations and elution of metal ions from acid corrosion phenomena. Elution samples were analyzed by inductively coupled plasma mass spectrometry, detecting residual ion concentration, while surface changes were analyzed under scanning electron microscopy. Results showed stainless steel wires do not undergo significant erosion when exposed to most fluorinated mouthwashes but, at prolonged exposure, alloys elute gradually greater amounts of metals and Ni–Ti wires become more sensitive to some mouthwashes. Ions’ elution varies considerably, especially for Ni–Ti wires, if exposed to household fluorinated gels, for which significant negative values were obtained. Changes, affecting wires’ outer layer, negatively act on shiny appearance and luster, reducing corrosion resistance. Although examined orthodontic wires showed good chemical stability and low toxicity, surface corrosion from exposure to fluorinated agents was observed. Home use must be accompanied by clinician prescription and, for household dental gels, must follow manufacturers’ recommendations, ensuring prophylactic action without damaging alloys surfaces
Toward sustainable electronics: exploiting the potential of a biodegradable cellulose blend for photolithographic processes and eco‐friendly devices
No full textFlexible electronics has emerged as a promising field for the development of electronic devices with applications in wearables, biomedical sensors, and edible electronics. Biomaterials play a crucial role in fabricating flexible substrates, and the utilization of polymer blends offers exciting possibilities for tuning mechanical and chemical properties. This paper highlights the potential of a novel polymer blend based on ethyl cellulose (EC) and hydroxypropyl cellulose (HPC) in the fabrication of substrates for flexible electronics. By blending the two cellulose ethers, it is possible to tune the mechanical and chemical properties of the final substrate, tailored to meet specific requirements. To exploit such innovative green substrates for photolithographic processes, their stability, and processability is extensively investigated. The feasibility of photolithographic processes on such biodegradable and edible substrates is demonstrated by fabricating both resistive and capacitive sensors through standard photolithographic processes, presenting a breakthrough in terms of applicability. The utilization of such biomaterials holds tremendous potential for driving technological advancements in various fields. These materials pave the way for innovative devices catering to diverse applications, from agriculture to food and biomedicine. Importantly, they also promote a sustainable approach for their fabrication, laying the foundation for an environment-aware future of technological progress
Towards Green Dentistry: Evaluating the Potential of 4D Printing for Sustainable Orthodontic Aligners with a Reduced Carbon Footprint
No full textClear aligners have transformed orthodontic care by providing an aesthetic, removable alternative to traditional braces. However, their significant environmental footprint, contributing to approximately 15,000 tons of plastic waste annually, poses a critical challenge. To address this issue, advancements in 4D printing have introduced “smart” aligners with shape memory properties, enabling reshaping and reducing the number of aligners required per treatment. This study focuses on ClearX aligners, an innovative 4D-printed solution aimed at extending usage duration and minimizing environmental impact. Using a comprehensive suite of tests, including morphological, optical, and mechanical evaluations conducted via scanning electron microscopy, UV-Vis spectroscopy, infrared spectroscopy, and bending and strain assessments, we evaluated the optical and mechanical stability of the ClearX material before and after thermal activation. Our results demonstrate that ClearX aligners retain their structural and functional properties after reshaping. Temporary changes in transparency, observed only under prolonged treatment durations exceeding manufacturer recommendations, are fully reversible within 12 h and do not compromise the aligner’s usability. These findings support the potential of ClearX aligners to effectively combine patient-centered, high-quality orthodontic care with sustainable practices
