8,602 research outputs found

    The carmine maggiore bell tower: An inclusive and sustainable restoration experience

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    The preservation of cultural heritage needs a restoration design format that can only be achievable by an in-depth multidisciplinary approach. Besides, a sustainable project requires that the link between architecture and technology be expressed through a “conscious” approach to the building. Therefore, each design must be based on the in-depth knowledge of history, construction rules, and mechanical properties of buildings to be restored. The bell towers are among the most exposed to degradation and earthquake damage constructions for their intrinsic geometry and structure. The “Carmine Maggiore” bell tower is one of the most important symbols of Naples (Italy) and, at 72 m high, it has stood out for centuries against the city. The tower underwent many significant damages and structural changes over time. The design, here illustrated, was aimed at restoring and repairing this bell tower, preserving existing materials, without altering the signs of time. The paper shows the methodology followed in the project, which, starting from an in-depth historical analysis and a detailed geometric and diagnostic survey, through several structural analyses, allowed an “inclusive” project (restoration, structural, and lighting project) based on suitable solutions that meet all the requirements of compatibility, sustainability, and structural safety

    Assembly and Characterization of SAMs Formed by the Adsorption of Alkanethiols on Zinc Selenide Substrates

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    Alkanethiols HS(CH2)nCH3 (n = 7, 11, 15, 17) and the hydroxy functional thiol HS(CH2)12OH are shown to adsorb from solution onto zinc selenide crystals and form well-organized monolayers. The chemisorption of these organosulfur compounds has been studied using transmission Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and surface wetting properties. FTIR indicates that the longer chain alkanethiols (n = 15, 17) form well-defined SAMs with crystalline-like conformations of the chains within the monolayers. As the chain length decreases, there is less conformational order present in the monolayers. The orientation of the largely trans-zigzag alkyl chains on the surface is at a slight tilt off the surface normal direction, as indicated by the dichroism of the infrared spectra and the chain-length-dependent scaling of the mass coverage of the SAM. The structural data obtained by XPS and FTIR are compatible with the inferences derived from measurements of surface wetting properties. The thickness of the SAM layers calculated using XPS is found to be comparable to the thickness of alkanethiol SAMs formed on gold and other metal surfaces. Changes in the surface of the ZnSe crystal because of chemisorption of the thiols are illustrated by data from AFM imaging. The feasibility of forming cohesive patterned monolayers by microcontact printing is also demonstrated

    Morphological Characterization of Some Local Varieties of Fig (Ficus carica L.) Cultivated in Southern Italy

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    Figs (Ficus carica L.) are ancient fruits of the Mediterranean basin. In Southern Italy, they are particularly important in the traditional course of local cuisine. In Southern Italy, fig trees are rarely cultivated in specialized orchards but are present in association with other fruit trees (for example, olive, almond, pear, pomegranate, and grapevine). These mixed orchards are particularly important in the traditional agroecosystems of the south of Italy. This study reports preliminary results on the local fig variety’s leaf morphological characterization, aiming to elucidate the presence of synonymousness or homonymy for in situ and ex situ conservation and further exploitation. A field survey was carried out during the summer of 2018 in some areas of the Basilicata district. Thirty local putative varieties were collected, and each of them was identified by GPS coordinates and recorded photographically. Moreover, they were cataloged with the name of the Municipality of origin, year, details of growing location (main crop, mixed orchard, gardens, and single plants), approximate age, and the local name supplied by the donor. All relevant information was included in the accession code. Leaf samples were collected from each accession from medium-length shoots. A digital image of each leaf sample was captured using a digital camera. Leaf morphometric traits were recorded using ImageJ and statistically analyzed using the software PAST 4.11 to discriminate among fig accessions. The multivariate morphometric approach applied correctly classified more than 90% of the leaves and helped to discriminate among accession. Moreover, linear discriminant analysis helped to recognize the presence of different synonymousness and homonymy of different accessions. The results revealed that measured leaf morphometric aided by image analysis could be a simple and inexpensive accessions classification tool

    Effects of Surface Morphology on the Anchoring and Electrooptical Dynamics of Confined Nanoscale Liquid Crystalline Films

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    The orientation and dynamics of two 40-nm thick films of 4-n-pentyl-4‘-cyanobiphenyl (5CB), a nematic liquid crystal, have been studied using step-scan Fourier transform infrared spectroscopy (FTIR). The films are confined in nanocavities bounded by an interdigitated electrode array (IDA) patterned on a zinc selenide (ZnSe) substrate. The effects of the ZnSe surface morphology (specifically, two variations of nanometer-scale corrugations obtained by mechanical polishing) on the initial ordering and reorientation dynamics of the electric-field-induced Freedericksz transition are presented here. The interaction of the 5CB with ZnSe surfaces bearing a spicular corrugation induces a homeotropic (surface normal) alignment of the film confined in the cavity. Alternately, when ZnSe is polished to generate fine grooves along the surface, a planar alignment is promoted in the liquid crystalline film. Time-resolved FTIR studies that enable the direct measurement of the rate constants for the electric-field-induced orientation and thermal relaxation reveal that the dynamic transitions of the two film structures are significantly different. These measurements quantitatively demonstrate the strong effects of surface morphology on the anchoring, order, and dynamics of liquid crystalline thin films

    Investigation of the Temperature Effects on Copper Losses in Hairpin Windings

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    Today, an extensive electrification is occurring in all industrial sectors, with a special interest seen in the automotive and aerospace industries. The electric motor, surely, is one of the main actors in this context, and an ever-increasing effort is spent with the aim of improving its efficiency and torque density. Hairpin windings are one of the recent technologies which are implemented onto the stator of the electric motor. Compared to conventional random windings, it inherently features lower DC resistance, higher fill factor, better thermal performance, improved reliability, and an automated manufacturing process. However, its bottleneck is the high ohmic losses at high-frequency operations due to skin and proximity effects (AC losses), resulting in a negative impact on the temperature map of the machine. Nevertheless, while it is well-known that DC losses increase linearly with the operating temperatures, the AC losses trend needs further insight. This paper demonstrates that operating the machine at higher temperatures could be beneficial for overall efficiency, especially at high-frequency operations. This suggests that a paradigm shift is required for the design of electric motors equipped with hair-pin windings, which should therefore focus on a temperature-oriented approach. In addition, the effect of the rotor topology on AC losses, which is often overlooked, is also considered in this paper. The combination of these effects is used to carry out observations and, eventually, to provide design recommendations. Finite element electromagnetic and thermal evaluations are performed to prove the findings of this research

    Considerations on the preliminary sizing of electrical machines with hairpin windings

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    Although the standard preliminary sizing of electrical machines equipping random windings is well consolidated and is worldwide acknowledged to be a good starting point for the design, there is no proof of accuracy and confidence when it comes to hairpin windings. This winding technology is gaining extensive attention due to its inherently high slot fill factor, good heat dissipation, strong rigidity, and short end-windings. These features make hairpin windings a potential candidate for some traction application to enhance power and/or torque densities. In this paper, a comparative design is done using the classical sizing tools available in literature between two surface-mounted permanent magnet synchronous machines, one featuring a random winding and one with a hairpin layout. The study aims at highlighting the hairpin winding challenges at high frequency operations and at showing limits of applicability of these standard approaches when applied to this technology. For verification purposes, finite element evaluations are also performed

    Surface Effects on the Dynamics of Liquid Crystalline Thin Films Confined in Nanoscale Cavities

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    The dynamics of 4-n-pentyl-4\u27-cyanobiphenyl (5CB) nematic liquid crystalline thin films have been studied in real time using step-scan Fourier transform infrared spectroscopy (FTIR). In these studies, the liquid crystal was confined in a nanocavity defined and bounded by an interdigitated gold electrode array. The gold microstructures were microfabricated on a zinc selenide (IR-transparent) window. The 5CB interactions with the ZnSe substrate result in surface-induced ordering of the ultrathin layers (on the order of 40 nm). As the films increase in thickness, the nanoscale organization induced by the surface layer becomes a less significant contributor to the overall bulk structure of the sample. Time-resolved FTIR studies have enabled the measurement of rate constants for the orientation and relaxation of the thin films under an applied electric field as a direct function of confinement dimensions. Cell thicknesses ranging from 40 to 300 nm were studied. The measured rate behaviors demonstrate the strong effects of the interactions occurring between the surfaces of the ZnSe crystals and the 5CB on the dynamics of the liquid crystalline assembly. Time-resolved studies reveal kinetically inhomogeneous line shapes for thicker films while ultrathin films maintain kinetically homogeneous peaks, suggesting the development of liquid crystalline domains or other inhomogeneities over this length scale in the transition from the surface layer to bulk

    Comparative study of imiquimod 3.75% vs. photodynamic therapy for actinic keratosis of the scalp

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    Background/purpose: To assess efficacy, tolerability, adverse effects, recurrence, and aesthetic results of imiquimod 3.75% vs. photodynamic therapy with 5-aminolaevulinic acid (MAL-PDT) for actinic keratosis (AK). Methods: A small randomized, intraindividual right-left pilot study for AK treatment of multiple scalp lesions was performed. Patients were treated with imiquimod and subsequently MAL-PDT (on opposite sides of the scalp) 14 days apart. Study end points were evaluated with clinical and dermoscopic examinations at 1, 3, 6, and 12 months. Results: Nine male bald patients were enrolled. Imiquimod achieved a slightly higher overall clearance rate than MAP-PDT (68.1% vs 56.5%). According to AK degree of severity, clearance rates were greater for degree I and III with imiquimod (68.8%, 64.5% and 75% with imiquimod vs. 48%, 69.8%, and 66.7% for MAL-PDT, respectively). At 12 months, a slightly higher total recurrence rate was noted for imiquimod compared with MAL-PDT (9.9% vs. 8.6%); new lesions were 2 degree I for imiquimod and 4 degree I for MAL-PDT. For both treatments, pain was moderate/strong (even if MAL-PDT seems to be less tolerable) adverse effects are common and transient; aesthetic results excellent. Conclusion: Both imiquimod and MAL-PDT were effective in the reduction in the number of AK. In the long-term, both present a good effectiveness maintained over time with excellent aesthetic results. A combination or sequential therapy could optimize the management of the cancerization field

    Autonomous Light Management in Flexible Photoelectrochromic Films Integrating High Performance Silicon Solar Microcells

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    Commercial smart window technologies for dynamic light and heat management in building and automotive environments traditionally rely on electrochromic (EC) materials powered by an external source. This design complicates building-scale installation requirements and substantially increases costs for applications in retrofit construction. Self-powered photoelectrochromic (PEC) windows are an intuitive alternative wherein a photovoltaic (PV) material is used to power the electrochromic device, which modulates the transmission of the incident solar flux. The PV component in this application must be sufficiently transparent and produce enough power to efficiently modulate the EC device transmission. Here, we propose Si solar microcells (μ-cells) that are i) small enough to be visually transparent to the eye, and ii) thin enough to enable flexible PEC devices. Visual transparency is achieved when Si μ-cells are arranged in high pitch (i.e. low-integration density) form factors while maintaining the advantages of a single-crystalline PV material (i.e., long lifetime and high performance). Additionally, the thin dimensions of these Si μ-cells enable fabrication on flexible substrates to realize these flexible PEC devices. The current work demonstrates this concept using WO₃ as the EC material and V₂O₅ as the ion storage layer, where each component is fabricated via sol-gel methods that afford improved prospects for scalability and tunability in comparison to thermal evaporation methods. The EC devices display fast switching times, as low as 8 seconds, with a modulation in transmission as high as 33%. Integration with two Si μ-cells in series (affording a 1.12 V output) demonstrates an integrated PEC module design with switching times of less than 3 minutes, and a modulation in transmission of 32% with an unprecedented EC:PV areal ratio

    In situ polymerization of soil organic matter by oxidative biomimetic catalysis.

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    Background: Agricultural practices that enhance organic matter content in soil can play a central role in sequestering soil organic carbon (SOC) and reducing greenhouse gases emissions. Methods: We used a water-soluble iron-porphyrin to catalyze directly in situ oxidative polymerization of soil organic matter in the presence of H2O2 oxidant, with the aim to enhance OC stabilization, and, consequently, reduce CO2 emissions from soil. The occurred SOC stabilization was assessed by monitoring soil aggregate stability, OC distribution in water-soluble aggregates, soil respiration, and extraction yields of humic and fulvic acids. Results: Soil treatment with H2O2 and iron-porphyrin increased the physical stability of water-stable soil aggregates and the total OC content in small aggregates, thereby suggesting that the catalyzed oxidative polymerization increased OC in soil and induced a soil physical improvement. The significant reduction of CO2 respired by the catalyst- and H2O2-treated soil indicated an enhanced resistance of polymerized SOC to microbial mineralization. The catalyzed oxidative polymerization of SOC also significantly decreased the extraction yields of humic and fulvic acids from soil. Conclusions: The oxidative catalytic technology described here may become an efficient agricultural practice for OC sequestration in soils and contribute to mitigate global changes
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