Urban Air Mobility Vehicle and Fleet-level Life-Cycle Assessment Using a System-of-Systems Approach

Can Urban Air Mobility (UAM) systems constitute viable and sustainable mobility solutions? This question has increasingly been concerning scientists, companies, policy makers, and authorities as more and more UAM vehicle concepts are seeing the light of day. In order to come closer to answering this question and to demonstrate the dependencies and impacts of the numerous parameters used to describe a highly complex system of a fleet of UAM vehicles operating in an urban environment, this paper employs a System of Systems (SoS) approach. A collaborative SoS framework with an agent-based simulation is introduced, which connects the UAM vehicle design, fleet performance, vertiport network, and re-energizing infrastructure with a Life-Cycle Assessment (LCA). The framework is used to simulate four exemplary UAM fleet-operation scenarios based on two cities and two operational modes, namely urban and suburban operations. Different vehicle design configurations, e.g. multirotor and lift + cruise vehicles, are evaluated in each scenario based on respectively realistic Concepts of Operations (CONOPS). Additionally, two different points in time, namely 2025 and 2050, are considered and assessed for powering the vehicles by taking into account the characteristics of batteries as well as the underlying electricity mix for their operation. Lithium nickel manganese cobalt oxide battery and lithium-sulfur (Li-S) batteries are considered. The SoS framework helps to asses various UAM metrics such as the average wait time for a passenger, the ideal number of aircraft needed for transporting all passengers within given time, the energy required on a vehicle and fleet level, sustainability metrics, e.g. the global warming potential associated with the energy carriers and many more. The capability to explore a wide design space and to visualize the dependencies between the system parameters and their impacts on different SoS metrics provides stakeholders with a helpful tool for their decision making

Flujos digitales en beneficio de una atención integral y complementaria del paciente con necesidades estéticas y funcionales

Introducción: el flujo de trabajo digital se define como una secuencia de procesos compuesta por ayudas computarizadas que suponen: la adquisición de imágenes, el diseño asistido por ordenador (CAD), el maquinado asistido por ordenador (CAM) y la posproducción del resultado logrado. La tecnología digital en Odontología, si bien está asociada en gran parte a los sistemas CAD/CAM, involucra, además, diversos dispositivos que hoy son de uso diario en la consulta odontológica y que facilitan la virtualización del paciente. Objetivo: conceptualizar la secuencia de tratamiento basada en el diagnóstico, planificación, ejecución y mantenimiento; y su complementación con otros procedimientos, todos digitalmente guiados, con efectos positivos en la rehabilitación oral de un paciente. Caso clínico: paciente masculino de 59 años, con desgastes de bordes incisales, alteraciones cromáticas, estéticas y funcionales (ausencia de guía anterior) del grupo dentario anterosuperior de canino a canino, con lateral superior derecho con fractura coronaria, proporción corono radicular insuficiente y relleno endodóntico defectuoso. Se realiza exodoncia guiada de la pieza 1.2 y colocación de implante, posteriormente se realizaron las preparaciones dentarias de canino a canino superior con chamfer. Se diseñaron digitalmente las restauraciones parciales estéticas en cerámica feldespática policromática. El implante dental se rehabilitó con un pilar fresado en cerámica feldespática con di silicato de litio y se colocó corona de cerámica feldespática. Finalmente se elaboró férula de estabilización y a los 14 meses se realizo un control.Introduction: The digital workflow is defined as a sequence of processes composed of computerized aids that involve: the acquisition of images, computer-aided design (CAD), computer-aided machining (CAM) and post-production of the achieved result. Digital technology in Dentistry, although it is largely associated with CAD/CAM systems, Digital technology in Dentistry, although it is largely associated with CAD/CAM systems, it also involves various devices that today are of daily use in the dental office and that facilitate the virtualization of the patient. Objective: to conceptualize the treatment sequence based on diagnosis, planning, execution and maintenance and its complementation with other procedures, all digitally guided, with positive effects on a patient's oral rehabilitation. Clinical case: 59-year-old male patient, with incisal edge wear, chromatic, aesthetic and functional alterations (absence of anterior guidance) of the upper anterior tooth group from canine to canine, with upper right lateral crown fracture, insufficient crown-root ratio and filling endodontic defect. Guided extraction of piece 1.2 and implant placement were performed, then dental preparations were made from canine to upper canine with chamfer. Esthetic partial restorations in polychromatic feldspathic ceramics were digitally designed. The dental implant was restored with a lithium disilicate feldspathic ceramic milled abutment and a feldspathic ceramic crown was placed. Finally, a precision splint was made and a control was performed at 14 months.OdontólogoCuenc

Prospective Life Cycle Assessment of Future Propulsion Systems for Aviation: A Fuel-cell Based Auxiliary Unit for a Commercial Aircraft

According to the Air Transport Action, in 2020 the aviation sector represented around 3,5 % of all anthropogenic climate impact. However, this figure is expected to grow in the future due to the increasing demand for commercial flights. Therefore, there is a need to reduce the environmental impacts of aviation in the long term and to start evaluating the environmental performance of novel lower-emission propulsion technologies. In this context, the project EXACT of the German Aerospace Center (DLR) investigates different aircraft concepts to achieve sustainable a commercial flight by 2040. One of the conceptual aircrafts considers gas turbines combusting hydrogen for propulsion, supported by fuel cells generating electric energy for auxiliary onboard power. Although this system has already been successfully demonstrated for small electric loads in commercial aircraft, there are still some challenges that need to be addressed until the technology reaches maturity and becomes competitive. For instance, the fuel cell system should have a low system mass but also be able to achieve a high efficiency. To investigate the potential environmental impacts of such emerging technologies in the future, different prospective methods are employed within the context of a life cycle assessment. Based on this specific aircraft concept, we conducted a prospective life cycle assessment for the production phase of the fuel cell-based auxiliary power unit. As the commercial aircraft is expected to enter the market in 2040, uncertainty arises and should be considered in the analysis. Thus, our contribution demonstrates the application of prospective methods and uncertainty analysis in this specific use case, by: • Describing the methodology used to conduct a prospective life cycle assessment of the production phase of a PEM fuel cell-based auxiliary power unit for a hydrogen-powered commercial aircraft • Identifying environmental hotspots in terms of climate change, resource availability, water scarcity, ecotoxicity, etc. within the production phase of the system • Depicting the approaches used to characterize the uncertainty present in the life cycle inventory data • Including parameter uncertainty of the foreground and background system in the analysis and interpretation of the result

Clinical outcomes of the biologically oriented preparation technique (BOPT) in fixed dental prostheses: A systematic review

Statement of problem: The biologically oriented preparation technique is a concept with a vertical tooth preparation, gingitage, an immediate interim restoration preserving the clot, and a specific laboratory technique aiming to adapt the marginal periodontal tissue to a remodeled emergence profile of the crown. However, the published scientific evidence on this subject is limited. Purpose: The purpose of this systematic review was to analyze whether using the biologically oriented preparation technique leads to improved clinical outcomes in terms of probing depth, gingival inflammation index, gingival marginal stability, and fewer mechanical and biological complications. Material and methods: Recommendations from the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were used in this systematic review. An electronic search of the MEDLINE/PubMed, EMBASE, Science Direct, Wiley Online Library, Cochrane, and ProQuest databases was made for articles published between March 2010 and July 2021 using keywords. Three reviewers selected and analyzed all articles that mentioned the biologically oriented preparation technique and met the inclusion criteria. Results: A total of 6 articles met the inclusion criteria: 1 prospective randomized clinical study, 1 randomized clinical study, 1 prospective clinical study, and 3 case series. According to these studies, of all the teeth treated with the biologically oriented preparation technique, probing depth (greater than 3 mm) increased in only 2.3%, gingival inflammation was present in 22.8%, gingival recession occurred in 1.7% (decreased gingival stability), and mechanical and biological failures occurred in 4.4% of the teeth. Conclusions: Fixed dental prosthesis treatments performed following the concept of the biologically oriented preparation technique did not increase probing depth and showed a moderate rate of gingival inflammation, lower recession rates, and lower mechanical and biological failures at the 5-year follow-up. The biologically oriented preparation technique appears to be a viable alternative technique for obtaining satisfactory and stable clinical results up to 5 years. Long-term randomized clinical trials are recommended to reach more conclusions about this protocol