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Uncertainty of facade sound insulation by a Round Robin Test. Evaluations of low-frequency procedure and single numbers
No full textThe international standard ISO 140-5 for the measurement of the sound insulation of building facades has been recently replaced by the new standard ISO 16283-3. The revised standard includes the procedure for measurements at low frequencies down to 50 Hz. The uncertainty of facade sound insulation, in particular at low frequencies, was evaluated by a Round Robin Test, conducted in a full-scale experimental building at the Construction Technologies Institute of the National Research Council of Italy (ITCCNR). Each of the 10 teams involved in the RRT replicated the tests 5 times, for a total of 50 measurements. The different measurement positions inside the receiving room were compared. In particular, all the teams involved in the RRT followed the low-frequency procedure, assessing corner and center room positions; the energy average values according to ISO 16283-3 were considered and the relative uncertainty, in terms of repeatability and in situ reproducibility standard deviations, was compared with the ones measured and calculated following the default measurement procedure. It was found that the uncertainty of the low-frequency procedure is higher than that of the default procedure. This would suggest the need to investigate further the reliability of the low-frequency procedure. At high frequency, the significant uncertainty values found are probably caused by the loudspeakers directivity and position; this aspect need to be investigated in greater detail, as wel
Scalability of ONOS reactive forwarding applications in ISP networks
No full textSoftware Defined Networking (SDN) is a powerful approach that enhances network control and management, and provides a flexible way to develop network applications. However, scalability of SDN networks is an important concern for many network operators. The main peculiarities of SDN when applied to an Internet Service Provider (ISP) network are the large geographical extension and the need of in-band transmission of control traffic. Therefore, the control traffic exchanged between the SDN controller and the network nodes must be carefully evaluated for the network design and dimensioning. We consider an ISP network controlled by the recently ONOS (Open Network Operating System) controller developed by ON.Lab. We devise a quantitative model to compute the exact number of exchanged OpenFlow messages and the corresponding bandwidth needed to install a traffic flow when running the default ONOS layer-2 forwarding applications. We compute also the exact number of flow rules installed in each switch. We show the general applicability of our models for a Point Of Presence (POP) network and for a large set of real nation-wide and world-wide ISP networks. Our quantitative models can be used for a safe network planning also when the network applications are not fully reactive
Thinking with interactive artifacts: Reflection as a concept in design outcomes
No full textReflection is a recurring notion in the HCI/interaction design literature. Throughout the years "reflection" has been highlighted as a key dimension of design thinking and as an important ingredient of design processes. In this paper we take stock in our community's interest in reflection and we suggest that while it has been acknowledged as a cornerstone for design processes, it has been less explored as a basis for design outcomes. In an attempt to approach this research problem, we conducted an extensive literature study. This study included a keyword analysis first in Scopus database and then in ACM library. In total, we filtered among 1,771 scientific papers. Given this extensive literature study, it seems that 1) the interest in this area is growing and we present tables that illustrate this growing interest over time, 2) reflection and behavioral change are two interrelated notions, and 3) these notions are well-explored in our field. Further on, we suggest that as interaction design is increasingly exploring the design of "tangible", "smart", "connected" and even "intelligent" artifacts, we should think about how reflection, and our ability to "think with artifacts" can be extended to include the design of interactive artifacts. In this paper we suggest how that might be done and we point at a design space for designing such interactive artifacts to think with
Core-substituted naphthalenediimides anchored on BiVO4 for visible light-driven water splitting
No full textIn this work, a novel catalytic system for the sunlight-driven water splitting reaction, which exploits the photocatalytic ability of BiVO4 coupled to a new kind of noble-metal-free organic dye molecules, is proposed. Hence, mono- and di-substituted naphthalenediimides (NDIs) were designed to have different functional groups that provide to them both tunable optical properties and adjustable HOMO/LUMO levels, and were selectively prepared (starting from 1,4,5,8-naphthalenetetracarboxylic acid) achieving yields >69%. Smart anchoring groups (i.e. carboxylates or aromatic amines) were added to the dyes in order to allow them to covalently bond to acidic -OH groups present on the BiVO4 surface. An easy and low-cost room temperature dip-coating technique was used to dye-sensitize both BiVO4 powders and thin films. NMR, MS, FT-IR, TG, FESEM, XRD, XPS and optical analyses confirmed the successful organic synthetic routes and good dyes/BiVO4 linkages. Photochemical and photoelectrochemical water oxidation reaction tests, together with DFT calculations, demonstrated that a proper alignment of the semiconductor/NDI-based dye energy levels is fundamental for enhancing the photocatalyst performance through a Z-scheme mechanism. The ability of the NDI organic molecules to delocalize the electronic charges was also a key factor for minimizing recombination processes and achieving more than a ten-fold increase in the photocurrent density of a 6 cm2 BiVO4 photo-electrode. The here reported results open new perspectives for the utilization of this new series of core-substituted NDIs, which are able to improve the activity of photocatalysts for different sunlight-driven applications, e.g. waste water treatment and organic contaminants' degradation, other than the production of solar fuels by water splitting mechanisms
An Optimal Scheduling for Medical Equipment Preventive Maintenance Over a Finite Planning Horizon Using Ant Colony Algorithm
No full textThe importance of preventive maintenance management has been gradually recognized specially with the great attention to the role of health technology management. Finding the optimal schedule to perform preventive maintenance for medical equipment is rarely considered in the literature. This research suggests using ant colony optimization method to solve the problem of finding the optimal preventive maintenance schedule. We developed 2 versions of the algorithm, both starting from a prioritized medical equipment list and differing in the heuristic function. The experimental results indicate the effectiveness of the ant colony optimization algorithm for this kind of problems
Highly active platinum supported Mo-doped titanium nanotubes suboxide (Pt/TNTS-Mo) electrocatalyst for oxygen reduction reaction in PEMFC
No full textIn this study, an innovative carbon-free electrocatalyst for oxygen reduction reaction was synthesized depositing platinum on titanium nanotube suboxide (trititanium pentoxide nanotubes, TNTS) obtained from titania doped with molybdenum (Pt/TNTS-Mo). The TNTS-Mo support was synthesized in autoclave, while the Pt/TNTS-Mo using the polyol method. The carbon-free support and the Pt-based catalyst were fully characterized via rotating disk electrode (RDE) technique and polymer exchange membrane fuel cell (PEMFC) station by preparing a membrane electrode assembly (MEA) with Nafion® 115, loaded with 0.35 mgPt cm−2 of Pt/TNTS-Mo at the cathode, and 0.35 mgPt cm−2 of commercial Pt/C (E-TEK) at the anode. In RDE experiments, the Pt/TNTS-Mo exhibited low overpotential and remarkable electroactivity toward oxygen reduction reaction (ORR: mass activity of 110.7 mA mgPt−1 at 0.9 V vs SHE). Moreover, the Pt/TNTS-Mo demonstrated excellent stability. Tests in a 25 cm2 single cell PEMFC resulted to maximum power density of 0.52 Wcm−2
Design, Synthesis, and Structure-Property Relationships of Er3+-Doped TiO2 Luminescent Particles Synthesized by Sol-Gel
No full textTitania particles doped with various concentrations of Erbium were synthesized by the sol-gel method followed by different heat treatments. The shape and the grain growth of the particles were noticeably affected by the concentration of Erbium and the heat treatment conditions. An infrared emission at 1530 nm, as well as green and red up-conversion emissions at 550 and 670 nm, were observed under excitation at 976 nm from all of the synthesized particles. The emission spectra and lifetime values appeared to be strongly influenced by the presence of the different crystalline phases. This work presents important guidelines for the synthesis of functional Er3+-doped titania particles with controlled and tailored spectroscopic properties for photonic applications
EMI-Induced Distortion of Baseband Signals in Current Feedback Instrumentation Amplifiers
No full textThe continuous trend toward the miniaturization of modules, comprising high sensitive devices alongwith noisy circuits likewireless transceivers and digital core blocks, has led us to investigate the effect of disturbances on analog front-end circuits used in system-in-package modules. In this context, this paper focuses on the distortion of radio frequency interference in CMOS current feedback instrumentation amplifiers like those used in MEMS readout circuits. The way baseband signals are distorted by such amplifiers, when the interference is superimposed onto the input signals, is analyzed referring to a math model, to computer simulations and to measurements carried out on a test chip designed and fabricated specifically for this purpose
