Factors affecting the adoption and use of urban air mobility

Technological advances have recently led to the development of urban air mobility (UAM), an alternative transportation mode with several concepts including vehicles operated by on-demand fully-automated vertical take-off and landing aircraft (VTOL) for intra-city passenger transportation. However, despite a growing interest in UAM, understanding users’ perceptions to it remains limited. This research aims to identify and quantify the factors affecting the adoption and use of UAM, based on relevant tools from the literature, such as recurring factors in studies on aerial vehicle concepts, ground autonomous vehicles, but also acceptance models, such as the Technology Acceptance Model by Davis et al. (1989). A stated-preference survey was developed to assess the perception of users in terms of adoption time horizon, including options such as the first six years of the service’s implementation, “unsure”, and “never”. The obtained results were evaluated using exploratory factor analyses, and the specification and estimation of suitable discrete choice models, multinomial logit models (MNLs) and ordered logit models (OLMs), with adoption time horizon as dependent variable. Findings revealed the importance of safety and trust, affinity to automation, data concerns, social attitude, and socio-demographics for adoption. Factors, such as the value of time savings, the perception of automation costs, and service reliability, were also found to be highly influential. There was also an indication that skeptical respondents, i.e. answering “unsure”, had a behavior similar to late and non-adopters, i.e. adoption time horizon higher than six years or answering “never”. The summarized results were represented in an extended Technology Acceptance Model for urban air mobility, and provided insights for policymakers and industrial stakeholders

Strategic planning for urban air mobility: Perceptions of citizens and potential users on autonomous flying vehicles

World’s current mobility systems are often inefficient and unsustainable, therefore the need for new schemes to satisfy mobility needs appears. This quest has given the impetus to the industry to invest in new technologies such as autonomous systems enabling self-driving vehicles. In this context, the concept of Urban Air Mobility (UAM), a term used for short-distance, on-demand, highly automated, passenger or cargo-carrying air mobility services, has arisen. This paper presents the introduction phase of strategic planning for the era of urban air mobility focusing on user and citizen acceptance of the system required for its operation. A survey is designed to capture the perception of citizens and potential users on aspects such as safety, security, well-being of the society (including issues of aesthetics, quality of life, social impacts), driving behaviour, mobility behaviour, expected benefits and their impact on the acceptance and the intention to use these systems. The acceptance of citizens and potential users (considered as two different groups) is analysed in terms of its potential uses (e.g. health emergencies, leisure, connectivity to remote regions). The survey is applied to the Metropolitan area of Lisbon and 207 responses were gathered. The collected data was analysed through correlation analysis and non-parametric tests. Conclusions are made on perceptions of citizens over different adoption and embracement levels.info:eu-repo/semantics/acceptedVersio

Photo-induced dynamics of the heme centers in cytochrome bc 1

The ultrafast response of cytochrome bc1 is investigated for the first time, via transient absorption spectroscopy. The distinct redox potentials of both c1- and b-hemes allow for a clear differentiation of their respective signals. We find that while the c1-heme photo-product exhibits the characteristics of a 5-coordinated species, the b-hemes presumably undergo photo-oxidation at a remarkably high quantum yield. The c1-heme iron–ligand recombination time is 5.4 ps, in agreement with previous reports on homologous cytochromes. The suggested photo-oxidized state of the b-hemes has a lifetime of 6.8 ps. From this short life-time we infer that the electron acceptor must be within van der Walls contact with the heme, which points to the fact that the axial histidine residue is the electron acceptor. The different heme-responses illustrate the flexibility of the c1-heme ligation in contrast to the more rigid b-heme binding, as well as the higher electronic reactivity of the b-hemes within the bc1 complex. This study also demonstrates the remarkable connection between the heme local environment and its dynamics and, therefore, biological functio

Effect of Maturation on Hemodynamic and Autonomic Control Recovery Following Maximal Running Exercise in Highly Trained Young Soccer Players

The purpose of this study was to examine the effect of maturation on post-exercise hemodynamic and autonomic responses. Fifty-five highly trained young male soccer players (12–18 years) classified as pre-, circum-, or post-peak height velocity (PHV) performed a graded running test to exhaustion on a treadmill. Before (Pre) and after (5th–10th min, Post) exercise, heart rate (HR), stroke volume (SV), cardiac output (CO), arterial pressure (AP), and total peripheral resistance (TPR) were monitored. Parasympathetic (high frequency [HFRR] of HR variability (HRV) and baroreflex sensitivity [Ln BRS]) and sympathetic activity (low frequency [LFSAP] of systolic AP variability) were estimated. Post-exercise blood lactate [La]b, the HR recovery (HRR) time constant, and parasympathetic reactivation (time-varying HRV analysis) were assessed. In all three groups, exercise resulted in increased HR, CO, AP, and LFSAP (P < 0.001), decreased SV, HFRR, and Ln BRS (all P < 0.001), and no change in TPR (P = 0.98). There was no “maturation × time” interaction for any of the hemodynamic or autonomic variables (all P > 0.22). After exercise, pre-PHV players displayed lower SV, CO, and [La]b, faster HRR and greater parasympathetic reactivation compared with circum- and post-PHV players. Multiple regression analysis showed that lean muscle mass, [La]b, and Pre parasympathetic activity were the strongest predictors of HRR (r2 = 0.62, P < 0.001). While pre-PHV players displayed a faster HRR and greater post-exercise parasympathetic reactivation, maturation had little influence on the hemodynamic and autonomic responses following maximal running exercise. HRR relates to lean muscle mass, blood acidosis, and intrinsic parasympathetic function, with less evident impact of post-exercise autonomic function

Digital audio and speech watermarking based on the multiple discrete wavelets transform and singular value decomposition

The ever-increasing illegal manipulation of genuine audio products has been a dilemma for the music industry. This situation calls for immediate, yet effective, solutions to avoid further financial losses and intellectual property violations. Audio and speech watermarking has been proposed as a possible solution, since this technology embeds copyright information into audio files as a proof of their ownership. In this paper, we propose an effective, robust, and an inaudible audio and speech watermarking algorithm. The effectiveness of the algorithm has been brought by virtue of applying a cascade of two powerful mathematical transforms; the discrete wavelets transform (DWT) and the singular value decomposition (SVD). Experimental results will be presented in this paper to demonstrate the effectiveness of the proposed algorithm

Does capital structure matter? Evidence from family-owned firms in Jordan

Purpose This study examines the potential impact of capital structure on the financial performance of family-owned firms in Jordan. Design/methodology/approach Using panel data of 107 listed companies from 2019 to 2021, the authors use a multivariate regression model to empirically examine the role that family firms' capital structure can play in engendering financial performance in the short and long terms. Findings This study's evidence indicates that family businesses rely on equity as their primary source of funding. This approach has been proven to be detrimental to their financial performance, as evidenced by the negative impact of capital structure on family firms' financial performance in the current study. Originality/value Capital structure-related decisions are essential to a firm's performance. Thus, there have been numerous empirical studies examining the relationship between capital structure and corporate performance in various settings worldwide. However, the findings of these studies are inconclusive. Also, there are relatively few empirical studies investigating the association between capital structure and the performance of family firms in emerging countries, particularly Jordan. This study, therefore, addresses this empirical gap in extant literature

Concepts for Reusing Composite Materials from Decommissioned Wind Turbine Blades in Affordable Housing

The very rapid growth in wind energy technology in the last 15 years has led to a rapid growth in the amount of non-biodegradable, thermosetting fiber reinforced polymer (FRP) composite materials used in wind turbine blades. This paper discusses conceptual architectural and structural options for recycling these blades by reusing parts of wind turbine blades in new or retrofitted housing projects. It focuses on large-sized FRP pieces that can be salvaged from the turbine blades and can potentially be useful in infrastructure projects where harsh environmental conditions (water and high humidity) exist. Since reuse design should be for specific regional locations and architectural characteristics the designs presented in this paper are for the coastal regions of the Yucatan province in Mexico on the Gulf of Mexico where low-quality masonry block informal housing is vulnerable to severe hurricanes and flooding. To demonstrate the concept a prototype 100 m long wind blade model developed by Sandia National Laboratories is used to show how a wind blade can be broken down into parts, thus making it possible to envision architectural applications for the different wind blade segments for housing applications