Nitrogen fertilization in wet and dry climate

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Synthesis of highly ordered L1 0 MPt alloys (M= Fe, Co, Ni) from crystalline salts: an in situ study of the pre-ordered precursor reduction strategy

The synthesis of highly ordered magnetic L10 alloys by means of the so-called pre-ordered precursor reduction (PPR) approach is deeply investigated by in situ X-ray absorption spectroscopy experiments. By following the chemical and structural evolution of the M(H2O)6PtCl6 (M = Fe, Co, Ni) precursor salts during hydrogen-assisted thermal reduction, it was possible to shed light on the key role of the crystalline initial compound whose intrinsic atomic order serves as a driving force to kinetically favor the formation of highly ordered FePt, CoPt and NiPt L10 alloys under milder conditions with respect to ordinary thermal treatments. The results confirm the potentiality of the PPR synthesis approach that can be suitably extended, by properly choosing the precursor salt, for the synthesis of other binary and ternary alloys where the chemical order represents a key property of the material, with a potential strong impact on several technological applications

Advanced documentation methodologies combined with multi-analytical approach for the preservation and restoration of 18th century architectural decorative elements at Palazzo Nuzzi in Orte (Central Italy)

This contribution reports the documentation of the conservation status and the pictorial technique of a wall painting and a stucco arch at Palazzo Nuzzi in Orte, central Italy (Viterbo district), achieved using a wide combination of non-invasive and micro-invasive diagnostic techniques. Specifically, a photogrammetric approach has been used for 2D and 3D ultraviolet fluorescence (UVF) acquisitions. Moreover, the conservation status of the wall painting has been also investigated by a non-invasive active infrared thermograghy technique, i.e. Pulse Compression Thermography (PuCT), used here for the first time on a wall painting to map the surface and sub-surface cracks in the first layers. Pigments, grounds and organic binders were characterised by X-ray fluorescence spectroscopy, micro-stratigraphic analysis, Fourier transform infrared spectroscopy and gas chromatography coupled with mass spectrometry. The results of this unique combination of advanced tools corroborated the historical-artistic attribution to the school of the architect Andrea Pozzo

Synthesis of highly ordered L10 MPt alloys (M = Fe, Co, Ni) from crystalline salts: an in situ study of the pre-ordered precursor reduction strategy

The synthesis of highly ordered magnetic L1(0) alloys by means of the so-called pre-ordered precursor reduction (PPR) approach is deeply investigated by in situ X-ray absorption spectroscopy experiments. By following the chemical and structural evolution of the M(H2O)(6)PtCl6 (M = Fe, Co, Ni) precursor salts during hydrogen-assisted thermal reduction, it was possible to shed light on the key role of the crystalline initial compound whose intrinsic atomic order serves as a driving force to kinetically favor the formation of highly ordered FePt, CoPt and NiPt L1(0) alloys under milder conditions with respect to ordinary thermal treatments. The results confirm the potentiality of the PPR synthesis approach that can be suitably extended, by properly choosing the precursor salt, for the synthesis of other binary and ternary alloys where the chemical order represents a key property of the material, with a potential strong impact on several technological applications

The use of pulse-compression thermography for detecting defects in paintings

Interest in the conservation of paintings grows year by year. Their periodic inspection is essential for their conservation over the time. Thermographic non-destructive inspection is one technique useful for paintings, but it is essential to be able to detect buried defects while minimising the level of thermal stimulus. This paper describes a pulse-compression infrared thermography technique whereby defect detection is optimized while minimising the rise in temperature. To accomplish this task, LED lamps driven by a coded waveform based on a linear frequency modulated chirp signal have been used on paintings on both a wooden panel and a canvas layer. These specimens contained artificially fabricated defects. Although the physical condition of each painting was different, the experimental results show that the proposed signal processing procedure is able to detect defects using a low temperature contrast

An ultrasonic metallic Fabry–Pérot metamaterial for use in water

Fabry-Pérot ultrasonic metamaterials have been additively manufactured using laser powder bed fusion to contain subwavelength holes with a high aspect-ratio of width to depth. Such metamaterials require the acoustic impedance mismatch between the structure and the immersion medium to be large. It is shown for the first time that metallic structures fulfil this criterion for applications in water over the 200–800 kHz frequency range. It is also demonstrated that laser powder bed fusion is a flexible fabrication method for the ceration of structures with different thicknesses, hole geometry and tapered openings, allowing the acoustic properties to be modified. It was confirmed via both finite element simulation and practical measurements that these structures supported Fabry-Pérot resonances, needed for metamaterial operation, at ultrasonic frequencies in water. It was also demonstrated the the additively-manufactured structures detected the presence of a sub-wavelength slit aperture in water

Trapped air metamaterial concept for ultrasonic sub-wavelength imaging in water

Acoustic metamaterials constructed from conventional base materials can exhibit exotic phenomena not commonly found in nature, achieved by combining geometrical and resonance effects. However, the use of polymer-based metamaterials that could operate in water is difficult, due to the low acoustic impedance mismatch between water and polymers. Here we introduce the concept of “trapped air” metamaterial, fabricated via vat photopolymerization, which makes ultrasonic sub-wavelength imaging in water using polymeric metamaterials highly effective. This concept is demonstrated for a holey-structured acoustic metamaterial in water at 200–300 kHz, via both finite element modelling and experimental measurements, but it can be extended to other types of metamaterials. The new approach, which outperforms the usual designs of these structures, indicates a way forward for exploiting additive-manufacturing for realising polymer-based acoustic metamaterials in water at ultrasonic frequencies

Infliximab in the treatment of Crohn's disease

The recent introduction of infliximab, a chimeric monoclonal antibody against tumor necrosis factor-alpha, has greatly modified the treatment of Crohn's disease (CD). Data from the literature show encouraging results after intravenous infusion both for closure of intestinal or perianal fistulas and for induction and maintenance of remission in patients with moderate to severe intestinal disease unresponsive to other treatments. However, some contraindications such as fibrostenosing CD and sepsis have been identified. In addition, the data on long-term outcomes and safety is still limited. Our initial experience showed that in selected cases local injection of infliximab is effective in the treatment of complex perianal disease offering the possibility of using such treatment even in small bowel obstructing disease with minimal systemic effects. This paper analyzes the state of the use of both intravenous and local injection of infliximab in patients with CD

Facile and fast synthesis of highly ordered L10-FeNi nanoparticles

The chemically ordered L1(0)-FeNi alloy is a promising candidate for next generation rare-earth-free permanent magnets, which can revolutionize the high-performance magnets market currently dominated by Nd-Fe-B. Despite many efforts, the experimental results fall short of theoretical predictions, and current approaches are not suitable for industrial implementation. In this work, we propose an innovative and efficient synthesis method that exploits the natural order of a crystalline Ni/Fe complex, which closely mimics the atomic organization in the L1(0) structure, to drive the formation of the ordered phase. By low-temperature reduction of the complex salt, carbon coated aggregates of FeNi alloy nanoparticles (20 - 120 nm) with a >55% of L1(0) phase, high coercivity (up to 65 mT) and large saturation magnetization (similar to 140 Am-2/kg) were obtained. The results pave the way for the development of a novel and sustainable route to produce high-anisotropy FeNi nanoparticles of potential interest for next generation critical-element-free permanent magnets

The interplay between single particle anisotropy and interparticle interactions in ensembles of magnetic nanoparticles

This paper aims to analyze the competition of single particle anisotropy and interparticle interactions in nanoparticle ensembles using a random anisotropy model. The model is first applied to ideal systems of non-interacting and strongly dipolar interacting ensembles of maghemite nanoparticles. The investigation is then extended to more complex systems of pure cobalt ferrite CoFe2O4 (CFO) and mixed cobalt-nickel ferrite (Co,Ni)Fe2O4 (CNFO) nanoparticles. Both samples were synthetized by the polyol process and exhibit the same particle size (DTEM 48 5 nm), but with different interparticle interaction strengths and single particle anisotropy. The implementation of the random anisotropy model allows investigation of the influence of single particle anisotropy and interparticle interactions, and sheds light on their complex interplay as well as on their individual contribution. This analysis is of fundamental importance in order to understand the physics of these systems and to develop technological applications based on concentrated magnetic nanoparticles, where single and collective behaviors coexist