Economic and Environmental Sustainability for Aircrafts Service Life

Aircrafts are responsible for a significant environmental impact mainly due to the air pollution caused by their motors. The use of composite materials for their production is a way to significantly reduce the weight of the structures and to maximise the ratio between the payload weight and the gasoline consumption. Moreover, the design phase has to consider the cost of different operations performed during the aircraft service life. During the entire life cycle, one of the main costs is the maintenance one. In the current literature, there is a lack of knowledge of methods for maintenance cost estimation in the aircraft industry; moreover, very few environmental assessment methods have been developed. Thus, the aim of this paper is to define a new method to support the aircraft design process; both the environmental and the economic dimensions have been included with the purpose of assessing the aircraft sustainability during its service life. A green index has been identified mixing the maintenance cost and an environmental parameter with the aim of identifying the greenest solution. A final practical application shows the feasibility and the simple application of the proposed approach

A Cost Estimation Approach for Aircraft Design Enhancement

This paper presents a novel reliability-based parametric methodology for quantifying the reliability of cost estimates for new composite aircraft components. In recent years, the aircraft production sector has increased its attention on optimizing their composite manufacturing operations. It has become clear that a key factor in the success of these operations is the consideration that not only technical factors, but also economic ones as well are relevant. Composite manufacturing variability is greatly influenced by many of these factors, and since manufacturing with composites is significantly more difficult than with more traditional materials, there are many sources of uncertainty that could influence the reliability of manufacturing cost estimates for new composite aircraft components. Therefore, it is worth considering these sources of uncertainty during the cost estimation process and to quantify the reliability of the cost estimates. To demonstrate the proposed methodology, a numerical example featuring a real-life composite aircraft component from a Boeing 787, with real-life data, is presented. Results show that the proposed methodology can quantify the uncertainty associated with cost estimates for new composite aircraft components in an effective manner, thereby supporting engineers in optimising the cost of their designs, helping them avoid errors in budget definition, and enabling them to allocate resources more efficiently

Increased myocardial apoptosis in patients with unfavorable left ventricular remodeling and early symptomatic post-infarction heart failure

AbstractObjectivesThe purpose of this study was to evaluate a potential correlation between apoptotic rate (AR), post-infarction left ventricular (LV) remodeling, and clinical characteristics in subjects who died late (≥10 days) after an acute myocardial infarction (AMI) with evidence of persistent occlusion of the infarct-related artery at autopsy.BackgroundApoptosis contributes to myocardiocyte loss in cardiac disease and may have a pathophysiologic role in post-infarction LV remodeling.MethodsThe AR was calculated at the site of infarction and in remote unaffected LV regions, using co-localization of in situ end labeling for deoxyribonucleic acid fragmentation and immunohistochemistry for caspase-3, in 14 subjects who died within two months after AMI. Correlation between AR and clinical characteristics such as age, site of AMI, transmural extension, multivessel coronary disease, and signs and/or symptoms of heart failure (HF), at the time of initial hospitalization for AMI or subsequently before death, was assessed using non-parametric statistical tests. Parameters of LV remodeling including diameters, free wall thickness, diameter-to-wall-thickness ratio, and mass were measured at gross examination at autopsy. Values are expressed as median (interquartile range).ResultsAmong clinical variables, early symptomatic post-infarction HF (9 cases, 64%) was associated with nearly fourfold increased AR at the site of infarction (26.2% [24.5% to 28.8%] vs. 6.4% [1.9% to 13.3%], p = 0.001). Moreover, AR both at the site of infarction and in unaffected regions was significantly correlated with parameters of progressive LV remodeling (p < 0.05).ConclusionsOur data show that in patients dying ≥10 days after AMI, myocardial apoptosis is strongly associated with and may be a major determinant of unfavorable LV remodeling and early symptomatic post-infarction HF

Produzione, qualità e analisi della filiera produttiva del lino da fibra in Italia

Fibre flax (Linum usitatissimum L.) is disappeared from the ltalian crop systems, while the textile industry has reached a leading position. The reintroduction of the crop is than potentially promising but the crop techniques and the production processes have to be set up. In 12 environments: crop development and growth, cultivar response, straw, fibre and seed yields, and fibre quality were analysed in the 1992-98 period. The data pointed out crop cycles of 176 and 110 d for the autumn and the spring sowing time respectively, corresponding to 1125 and 990°C d cumulated growing degree. Straw yield at pulling was on average of 6.3 t ha-1, with relevant differences among years and environrnents. Early maturity cultivar yielded more in the less favourable sites. N fertilization was occasionally relevant, and a generally distributions of 60 kg N ha-1 was the more effective. In the Mediterranean environments, with the autumn, sowing flax was more productive and the yield steady. The long fibre ratio was often low (10-13%) and the quality uneven because of the insufficient cleanliness due to retting difficulties. Occasionally, the value of the fibre was affected by the insufficient stem length. In the less dense crop, the seed yield was on average 0.9 t ha-1. Such productions were similar to those assessed for the more dense crop. In conclusion: because of the complexity of the interactions among the crop growth, the yield, the retting process and the fibre quality flax reintroduction is doubtful. In the production processes retting seems to be the crucial phase. Il lino da fibra (Linum usitatissimum L.) è da tempo assente negli ordinamenti colturali italiani, mentre è assai importante l'industria di filatura. La reintroduzione della coltura appare quindi potenzialmente promettente, ma richiede la messa a punto dell'agrotecnica e della filiera produttiva. Nel periodo 1992-1998 in 12 ambienti sono stati esaminati: lo sviluppo e la crescita della coltura, l'adattamento di cultivar, la produzione di paglia, fibra e seme, la resa alla stigliatura, la qualità della fibra. I dati raccolti evidenziano cicli colturali in media di 176 e 110 d rispettivamente per le semine autunnali (ambienti del centro-sud) e vemino-primaverili; corrispondenti a somme termiche di 1125 e 990°C d. La produzione di paglia alla estirpatura è stata in media di 6.3 t ha-1 con valori assai variabili tra annate e ambienti. Le varietà a ciclo corto sono apparse migliori nelle condizioni difficili. L'effetto della concimazione azotata è apparsa talvolta rilevante e comunque con dosi ottimali prossime a 60 kg ha-1 di N. Negli ambienti del centro-sud le semine autunnali si sono dimostrate spesso le più interessanti e sicure. La resa in fibra lunga è stata bassa (10-13%) e la qualità variabile per la scarsa pulizia dovuta alle difficoltà di macerazione. La modesta lunghezza tecnica dello stelo sovente riduce il valore del prodotto. In coltura rada, la produzione di seme è variata da 0.5 a 1.5 t ha-1; tali valori non si sono discostati in modo apprezzabile da quelli ottenuti in coltura fitta. In conclusione, la diffusione del lino appare problematica per le complesse interazioni tra la produzione, il processo di macerazione e la qualità della fibra. Soprattutto la macerazione appare il passaggio chiave

Human interleukin 17–producing cells originate from a CD161+CD4+ T cell precursor

We demonstrate that CD161 is a highly up-regulated gene in human interleukin (IL) 17 T helper cell (Th17) clones and that all IL-17–producing cells are contained in the CD161+ fraction of CD4+ T cells present in the circulation or in inflamed tissues, although they are not CD1-restricted natural killer T cells. More importantly, we show that all IL-17–producing cells originate from CD161+ naive CD4+ T cells of umbilical cord blood, as well as of the postnatal thymus, in response to the combined activity of IL-1β and IL-23. These findings implicate CD161 as a novel surface marker for human Th17 cells and demonstrate the exclusive origin of these cells from a CD161+CD4+ T cell progenitor

Maintenance Digital Twin using vibration data

Maintenance represents a critical aspect of manufacturing systems. Its optimization may lead companies to save costs related to production losses and can extend the whole lifecycle of assets or components. This paper aims at proposing a methodology for evaluating the behavior of systems for maintenance purpose by means of analysis carried out on real vibration data collected in the work environment. To this purpose, a digital twin approach has been developed and the statistical method of the control charts has been integrated to conduct the analysis about the vibration data. The methodology has been applied to a real case study in order to analyze the behavior of an electric motor used in the industrial sector and the results show that the method is effective in predicting possible failures that can lead to apply preventive maintenance actions. (C) 2022 The Authors. Published by Elsevier B.V

From Conservation to Revitalization. Ambiguous and Critical Conditions in the Heritage Conservation Experiences of Erice

The plans and the evolutionary trends of policies and practices implemented in Erice old town, in the south of Italy, in the western part of Sicily, can be considered a case study of total conservation as highly representative of Italian urban planning of the last 60 years. This paper aims to deal with the actual problems and the perspective of sustainable development of the historical centre of Erice, by adopting the approach of urban and territorial regeneration. This paper also highlights the historical and cultural context in which the Gubbio Charter (issued in 1960) is affirmed; i.e. the most appropriate approaches to historical urban centres; what we can learn from Erice’s integral conservation experience thanks to and/or without the direct influence of plans and other updated kinds of policy; some reflections regarding the rationale of differentiation in the urban/territorial functions and the actual asset and town management issues. In the final part of the paper, the authors propose a scenario in which the future of historical centres will no longer be based only on the quality of the safeguarding methods of restoration and recovery, nor on the ability of the architects/experts involved. The evidence of Erice’s recovery process, intended as an example of the protection and restoration models applied in Italy and in the foreign school of architectural restoration, shows that the social, economic, environmental and cultural aspects of the regeneration of the historical centres are intertwined and depend on the developmental conditions of the entire city. The experience of the complete recovery of the historical centre of Erice, where the restoration and accessibility of the buildings and the historical urban fabric was perfectly successful, did not, however, resolve the trend towards abandonment. The latest experiments to enhance the historical centre in a completely fresh and creative way, with the improvement of the accessibility system, could form the basis of a new urban and territorial role for the ancient part of the city. Without an integrated approach, it will be very difficult to regenerate historical centres; for this reason, it is indispensable to leverage on the interconnections between cultural built heritage and the entire urban context

A High Throughput Experimentation Protocol for Quantitative Measurements of Regioselectivity in Ziegler-Natta Polypropylene Catalysis

This paper introduces a High Throughput Experimentation method for fast and accurate evaluations of regioselectivity in Ziegler-Natta (ZN) propene polymerizations. With a simple protocol, the (very low) fraction of regioirregular 2,1 monomeric units in the polymers can be quantitated by means of 13C NMR chain-end analyses on single H2-terminated polypropylene samples. The method, that was successfully validated for three representative ZN catalyst systems, also provides information on catalyst ‘dormancy’ and propensity to undergo chain hydrogenolysis. This opens the door to the rapid and accurate implementation of Quantitative Structure-Activity Relationship (QSAR) databases of regioselectivity and ‘hydrogen response’ in this important industrial catalysis