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The direct chemical reactivity between phosphorus and nitrogen was induced under high-pressure and high-temperature conditions (9.1 GPa and 2000−2500 K), generated by a laser heated diamond anvil cell and studied by synchrotron X-ray diffraction, Raman spectroscopy, and DFT calculations. α-P3N5 and γ-P3N5 were identified as reaction products. The structural parameters and vibrational frequencies of γ-P3N5 were characterized as a function of pressure during room-temperature compression and decompression to ambient conditions, determining the equation of state of the material up to 32.6 GPa and providing insight about the lattice dynamics of the unit cell during compression, which essentially proceeds through the rotation of the PN5 square pyramids and the distortion of the PN4 tetrahedra. Although the identification of α-P3N5 demonstrates for the first time the direct synthesis of this compound from the elements, its detection in the outer regions of the laser-heated area suggests α-P3N5 as an intermediate step in the progressive nitridation of phosphorus toward the formation of γ-P3N5 with increasing coordination number of P by N from 4 to 5. No evidence of a higher pressure phase transition was observed, excluding the existence of predicted structures containing octahedrally hexacoordinated P atoms in the investigated pressure range.

Heterostructures of single- and few-layer black phosphorus (2D bP) functionalized with gold nanoparticles (Au NPs) have been recently reported in the literature, exploiting their intriguing properties and biocompatibility for catalytic, therapeutical and diagnostic applications. However, a deeper insight on the structural and electronic properties at the interface of the 2D bP/Au NP heterostructure is still lacking. In this work, 2D bP is functionalized with Au nanoparticles (NPs) through in situ deposition-precipitation heterogeneous reaction. The smallest realized Au NPs have a diameter around 10 nm as revealed by atomic-force and scanning electron microscopy, and are partially positively charged as revealed by X-ray Photoelectron Spectroscopy (XPS). XPS, UV-vis and Raman spectroscopy, supported by density functional theory (DFT) calculations, confirmed that while the structural and electronic properties of 2D bP are overall preserved, a soft-pairing between P atoms at the surface of 2D bP and Au atoms at the surface of Au NPs occurs, leading to a partial charge transfer at the 2D bP/Au interface, with a positive charge being localized on the Au atoms directly bonded to 2D bP. DFT calculations also predicted a band gap lowering, by 0.8 eV, for phosphorene functionalized with a tetranuclear Au cluster. Larger effects are expected as the Au cluster nuclearity (and coverage) increases.

Among 2D-materials exfoliated black phosphorus (i.e. phosphorene) [1] is still attracting a great interest mostly as a consequence of its peculiar electronic and optical properties, which encompass a strong anisotropic behavior, a tunable band-gap, dependent on the thickness of the exfoliated phosphorene flake, and a high electron mobility. These intriguing properties follow from the unique corrugated two-dimensional structure of this p-type semiconducting material and have stimulated a huge amount of research mostly addressed to explore and exploit its potential applications in different areas of physics and materials sciences and technologies. [2] In contrast, much less attention has been paid to study the chemical and biologic properties of this innovative material and only recently intriguing results have appeared also in these areas. [3,4] Here, we present our recent results showing that phosphorene could behave as an extended, flat, molecular platform to be used for catalytic applications. In particular, we have demonstrated that nanoparticles of different transition metals (nickel, copper, palladium, etc.) can decorate the surface of the exfoliated material imparting to phosphorene a higher chemical stability towards air oxidation and forming a sort of inert support to host catalytically active nanoclusters.[5,6] Remarkably, attempts to functionalize the surface of the few-layer exfoliated material with organopalladium precursors do not result in the formation of any organometallic derivative atop the polyphosphorus surface, but affords a very unusual nanocomposite featuring dipallada units covalently bonded amidst two contiguous layers of the exfoliated black phosphorus.[7] The seclusion of the palladium centers in this latter material, makes its catalytic activity in standard hydrogenation reactions dropping to zero, thus indirectly confirming the inaccessibility of the metal centers.

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Additive Manufacturing (AM) technologies have expanded the possibility of producing unconventional geometries, also increasing the freedom of design. However, in the designer&rsquo, s everyday work, the decision regarding the adoption of AM for the production of a component is not straightforward. In fact, it is necessary to process much information regarding multiple fields to exploit the maximum potential of additive production. For example, there is a need to evaluate the properties of the printable materials, their compatibility with the specific application, redesign shapes accordingly to AM limits, and conceive unique and complex products. Additionally, procurement and logistics evaluations, as well as overall costs possibly extending to the entire life cycle, are necessary to come to a decision for a new and radical solution. In this context, this paper investigates the complex set of information involved in this process. Indeed, it proposes a framework to support and guide a designer by means of a structured and algorithmic procedure to evaluate the opportunity for the adoption of AM and come to an optimal design. A case study related to an ultralight aircraft part is reported to demonstrate the proposed decision process.

Functionalization is one of the most powerful tools in materials science for the development of new and innovative materials with tailored properties purposefully designed to enhance the overall stability of the system. This is particularly true for exfoliated black phosphorus, which suffers from easy decomposition by air and moisture, hampering its highly desirable applications, especially in electronics. The present work suggests an innovative approach to the functionalization process of this 2D-material based on the selective introduction of chalcogen atoms on the material surface through a reaction with suitable molecular precursors such as stibine chalcogenides (R3Sb(X), X = O or S; R = organyl group). These molecules may readily act as chalcogen-transfer agents and, upon releasing the chalcogen atom atop the bP surface, leave stable stibines (R3Sb) as byproducts, which may be easily removed from the functionalized bP surface. The work provides an overview of all the possible structural, electronic and energy aspects associated with the chalcogen-atom transfer from the stibine to phosphorus based compounds, exemplified by trialkyl phosphines and single layer exfoliated black phosphorus, i.e. phosphorene, Pn. In both cases the oxygen transfer is more exergonic than the sulfur transfer, with the associated free energy barrier for the phosphine process being higher. Although the sulfur transfer for the Pn is found to be endergonic (ca. +3.6 kcal mol-1), the process may surely occur at high temperature. The evolution of the band structure upon the chalcogen transfer has been depicted in detail. This journal is

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Smart CPSs (S-CPSs) have been evolving beyond what was identified by the traditional definitions of CPSs. The objective of our research is to investigate the concepts and implementations of S-CPSs, and more specifically, the frameworks proposed for the fuzzy front end of their reasoning processes. The objectives of the paper are: (i) overview of the various framework concepts and implementations in the context of S-CPS, and (ii) analyze the presented frameworks from the points of view of reasoning processes of S-CPSs that included the concepts of structuring knowledge, building awareness, situated reasoning, decision making, and system adaptation. Our major findings are: (i) model-based and composability approaches do not support a development of S-CPSs; (ii) awareness and adaptation behaviors are considered as system level characteristics of S-CPSs that are not achieved by traditional design approaches; (iii) a new framework development should support a compositional design for reasoning in S-CPS. Based on the findings above, we argue that a development of S-CPSs should be supported by a proper framework development for compositional design of smart reasoning and coping with the challenges of compositionality requires both software-level integration and holistic fusion of knowledge by means of semantic transformations. It needs further investigation if a compositionality enabling framework should appear in the form of a meta-framework (abstract) or in the form of a semantically integrated (concrete) framework.

Companies are getting increasingly interested in learning how different customers use their products. Collecting data about the use of products provides useful insights and facilitates design enhancements. Effective data analytics needs dedicated tools. In this paper, we summarize the results of our literature research done with special attention to existing tools. We observed that everything is changing rapidly and getting more complex in terms of data and processing methods and tools. While remarkable attention has been paid to processing big data, much less is being devoted to effective semantic progressing of middle-of-life (MoL) data. One of our findings is that commercialized data analytics tools have not addressed extraction, aggregation, and handling genuine MoL data adequately. Another one is that the currently available tools are in the lack of the capability to adapt themselves to designers needs and to produce results that could be reused in multiple design tasks. Nowadays products are equipped with smart capabilities and this offers new opportunities for exploiting middle-of-life data. The knowledge aggregated in this study will be used in the development of a sophisticated toolbox. This will: (i) integrate various tools under a unified interface, (ii) implement various semantics orientated and smart reasoning-based functions, and (iii) facilitate data transformations by practicing designers in contexts.

The system concept is a widely-used concept in research and practice. Already in the 50s of the previous century, a community was created to investigate interrelationships between domains and create a theory surpassing and comparing domains. The General Systems Theory (GST) community has tried to come up with such a theory for several decades. The ambition has grown more realistic in the years after, recognizing that an all-encompassing theory would not be possible. Since then, systems research was aimed at generating useful and usable approaches to compare and interrelate domains, thus creating a trans-disciplinary approach to enable description and analysis of large, and even complex, systems. The concept of systems, however, is often loosely used. Levels of abstraction are neglected, and interrelationships between systems ignored. In this paper, the concept of system is put in historical context, and further elaborated upon in the context of complex and trans-disciplinary systems. Two examples of transdisciplinary systems are presented and discussed to illustrate the use of the system concept.

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Costs associated with unscheduled and preventive maintenance can contribute significantly to an airline's expenditure. Reliability analysis can help to identify and plan for maintenance events. Reliability analysis in industry is often limited to statistically based approaches that incorporate failure times as the primary stochastic variable, with additional strict assumptions regarding independence of events and underlying distributions of failure phenomena. This foregoes the complex nature of aircraft operations, where a whole range of operational factors may influence the probability of occurrence of a maintenance event. The aim of this research is to identify operational factors affecting component reliability and to assess whether these can be used to reduce the number of unscheduled occurrences (i.e. failures). To do so, a data-driven approach is adopted where historical operational and maintenance data is gathered and analysed to identify operational factors with a measurable influence on maintenance event occurrence. Both time-independent and time-dependent Proportional Hazard Models (PHMs), models which incorporate operational factors as covariates, are employed to generate reliability estimates. Results obtained from analysing historical data of a set of ten components with respect to unscheduled removals indicates that adopting new maintenance schedules, derived from the proposed reliability models, could reduce the number of unscheduled occurrences by approximately 37%. The potential benefits of adopting the proposed strategy are extensive. Nonetheless, numerous assumptions have been introduced to overcome challenges imposed by the complex nature of the data. To overcome these challenges, recommendations are made for future development of the proposed approach

The aircraft dispatch decision is a complex analysis based on many factors related to airworthiness regulations, aircraft health status, resource availability at current and future stop(s) and operational preferences of the operator. Within the turnaround time (TAT) a decision has to be made whether the aircraft can return to service, defects have to be deferred, operational restrictions apply, maintenance has to be performed, or if the aircraft is unable to safely perform the next flight. This paper presents a framework for automated dispatch decision support and, as a first step of implementation of the framework, a proof of concept for automated root cause identification by means of a case study on a Airbus A320 wing anti-ice valve. A decision tree algorithm has been applied to a synthetic dataset, representing historical failure data with associated root causes and observed symptoms, achieving correct classification of the root cause for 40% of the cases. Analysis of the results show that the accuracy of the method increases with an increasing number of symptoms associated to a root cause. Furthermore, the method cannot distinguish between root causes with similar symptoms. Although the use of synthetic data restricts conclusions that can be drawn from the results, the work shows a proof of concept for automated root cause identification and leads to initial findings that are essential for future implementation and optimisation of the method. Eventually, the framework will be operationalised in the form of a mobile tool to assist stakeholders in on-site aircraft dispatch decision support.

The present study develops a method for the sake of evaluating Disposal and Recycle (D&R) cost in view of the increasing demand in aircraft retirement. Firstly, a process model is extracted. The subordinated cost elements are also identified. Next, the cost aggregations based on the D&R process steps are discussed. Moreover, it proposes an economic indicator to support the determination of the aircraft D&R strategies. The indicator is used to evaluate the economic performance and to facilitate the trade-off studies among different D&R scenarios. This analysis is demonstrated on two aircraft types with two scenarios. In addition, sensitivity analysis evaluating the impact of the salvage value, residual value, D&R cost, and the learning factor is performed. It is found that the engine D&R possesses more economic gains than that of the aircraft. The salvage value and residual value are the main factors which influence the D&R economic performance.

tBu2P-P(SiMe3)Li reacted with [(eta6-C6H6)RuCl2]2 at -40 °C in the presence of PR3 (PR3 = PEt3, PEt2Ph, PEtPh2) by the nucleophilic addition of the tBu2P-P(SiMe3) moiety to the benzene ring to yield solely the complexes [(R3P)2Ru(Cl){eta5-C6H6(Me3SiP-PtBu2)}] (1). These products decomposed slowly at ambient temperature to yield benzene, Ru clusters, and small amounts of the dinuclear ruthenium complexes [{(R3P)2Ru}2(mu,eta2:2-P2)2Ru(PR3)2] (Ru-Ru) (6). Single-crystal X-ray diffraction studies of [(PhEt2P)2Ru(Cl){eta5-C6H6(Me3SiP-PtBu2)}] (1b) and [(Ph2EtP)2Ru(Cl){eta5-C6H6(Me3SiP-PtBu2)}] (1c) revealed that the addition of the tBu2P-P(SiMe3) group occurred through an exo pathway. Complex 6a (R = Et) displays a planar rectangular P4 system consisting of two P2 units and a Ru-Ru distance that lies in the range of a single bond.

Metal-Organic Frameworks (MOFs) are porous materials built from metal-containing nodes and organic linkers. The virtually infinite combination of these two ingredients for the construction of MOFs is the key factor that makes them so successful for their practical exploitation in several fields of contemporary materials science. Typical linkers are usually represented by polycarboxylic acids and polydentate N-heterocyclic bases (such as pyridines, imidazoles, pyrazoles and tetrazoles). There are fewer examples of spacers containing more than one heteroatom type in the heterocyclic core. The replacement of a carbon atom with a heteroatom (N, O, S) in the spacer structure modifies its electron density distribution. Heteroatoms may also be additional coordination sites for metal ions. Thiazoles are the simplest N,S-heterocycles. The simultaneous presence of a hard (N) and a soft (S) base may favour the coordination to both hard and soft metal ions, making the related ligand more versatile for MOFs design. With this in mind, assorted ligands featured by both condensate (TzTz) and bonded (Tz_Tz) thiazole rings have been synthesized and combined under solvothermal conditions with 3d metal salts to obtain MOFs. The results will be presented.

Chemical hydrogen storage with small lightweight and hydrogen-rich molecules like ammonia-borane (NH3?BH3, AB, 19.3 wt.% H2) or amino boranes of general formula RNH2?BH3 (R = alifatic chain or cycle) is a topic of great interest, as witnessed by the exponential growth of the number of papers published in the recent literature. Transition metal complexes can catalyze H2 release from these species under mild conditions and offer great potential as H-storage materials. The reactions of assorted Co(I), Ir(I), Pd(II) and Ru(II) polyphosphine (Figure 1) and pincer type complexes with AB and amine boranes have been analyzed experimentally through variable-temperaure multinuclear (11B, 31P, 1H) NMR spectroscopy, kinetic rate measurements and kinetic isotope effect (KIE) determination with deuterated isotopologues. At the same time, a DFT modeling of the reaction mechanisms has been carried out, starting from the experimental data available. The results will be presented.

The alkylation of arylamines using stoichiometric amounts of aliphatic and benzylic alcohols in the presence of tBuOK was carried out at 55 °C using a low catalyst loading of [Ru(cod)Cl2]n/PTA (1,3,5-triaza-7-phosphaadamantane). The overall borrowing-hydrogen process does not require a controlled nitrogen atmosphere, and it could also be carried out at room temperature using higher loading of base. A wide range of substrates can be used in this transformation, and it has a good tolerance of different substituents. This catalytic system proved also to be efficient for other hydrogen-transfer reactions such as a tandem oxidation/C-C coupling between 1-phenylethanol and primary alcohols.