Browsing by Tema "Aeronautics"

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A techno-economic and life cycle assessment of a new power and biomass to liquids (PBtL) configuration with negative emissions for producing sustainable aviation fuel (SAF)
(Elsevier BV, 2024) Maria Fernanda Rojas Michaga; Stavros Michailos; Evelyn Cardozo; Kevin J. Hughes; D.B. Ingham; Mohamed Pourkashanian
• Combined TEA and LCA of an integrated PBtL-CCS-SAF system. • The MJSP is OPEX intensive due to high electricity consumption, and biomass cost. • The WtWa GWP is negative for all the PBtL-CCS scenarios and falls below the UK-SAF mandate threshold. • The WtWa water footprints of the PBtL-CCS are greater than the one of fossil jet fuel. • SAF certificates could help to break-even with the conventional jet fuel. A novel configuration of the hybrid Power-and-Biomass to Liquids (PBtL) pathway for producing sustainable aviation fuels (SAF) has been developed and assessed from a techno-economic and environmental perspective. The proposed configuration can achieve negative emissions and hence a new bioenergy with carbon capture and storage (BECCS) route is proposed. The amount of CO 2 that is captured within the process and that is sent for storage ranges from 0 % to 100 %, defining the various PBtL-CCS scenarios that are evaluated. Mass and energy balances have been established through process modelling in Aspen Plus and validated using data available in the literature. Further, the System Advisor Model (SAM) tool was used to model a dedicated offshore wind farm, based on location specific wind data. Results from the technical assessment have set the foundation for economic and environmental evaluations. The economic evaluation of the proposed SAF production configurations estimates minimum jet fuel selling prices (MJSP) ranging from 0.0651 to 0.0673 £/MJ, mainly driven by electricity consumption and feedstock cost. Costs for CO 2 compression, transport, and storage have a small contribution to the MJSPs of all the proposed scenarios. Global warming potentials range from −105.33 to 13.93 gCO 2eq /MJ, with PBtL-CCS scenarios offering negative emissions and aligning with the aviation industry’s net-zero ambition for 2050. Water footprints range from 0.52 to 0.40 l/MJ, mainly driven by the water requirements of the alkaline electrolyser and refinery, followed by the wind electricity water footprint. Based on the outputs of the assessments, the resulting SAF could benefit of the support proposed by the UK SAF mandate, which could boost their economic performance by awarding certificates with monetary value. Estimates indicate that the cost of certificates that breakeven the fossil jet fuel price could reduce if negative emissions are also rewarded under this scheme. Overall, the study introduces for the first time and assesses a novel net-negative SAF configuration, and the new information generated provides meaningful insights to a variety of stakeholders such as process developers, academics and policy makers.
Aseguramiento Universal en Salud en el Perú
(2009) Oscar Ugarte Ubillúz
Book Review: Rohm and Haas: History of a Chemical Company, by Charles Cheape
(1987) Charles W. Cheape
Broadcasting System of Nagano Olympic Winter Games
(1998) Kenzo Muroi; Takashi Miyamoto; Ken-ichi Hashimoto; Kazuo Higuchi; Shoji Kanazawa; Hiromi Sueishi; Michihiko Hayashi; Hideaki Momozawa; Katsuya Higuchi; Noriaki Kumada
Colombian guerrillas disarm, starting their risky return to civilian life
(2017) Camille Boutron
Computational Prediction of a Vehicle Aerodynamics Using Detached Eddy Simulation
(2013) Natalia Castro; Omar López; Luis Muñoz
<div class="section abstract"><div class="htmlview paragraph">In the present paper, Computational Fluid Dynamics (CFD) simulations of the aerodynamics of a station wagon using DES (Detached Eddy Simulation), based on the Spalart-Allmaras turbulence model, are discussed and compared with experimental results. DES is a non-zonal hybrid turbulence model that uses both Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES), enabling a better equilibrium between the accurateness and the computational cost of the solution.</div><div class="htmlview paragraph">Simulations were run in parallel using the commercial software ANSYS/FLUENT v13.0, and required a computational grid of approximately 50 million cells. Some flow characteristics such as boundary layer separation, recirculation zones, and the entire pressure and velocity field were also obtained and analyzed. Computational results of drag force were compared with experimental results based on the SAE J1263 recommended practice (which describes a way to calculate the resistive loads that act on a vehicle during non- forced deceleration). Changes were made in the experimental estimation of the drag force, compared to the procedure stated in SAE J1263 (e.g., a differential formulation of the system was used, and the mass of the vehicle was altered by loading extra bodies into the vehicle). A selection among different sets of experimental conditions (vehicle velocities and vehicle weights) was made to improve the accuracy of the prediction.</div><div class="htmlview paragraph">Even though computational and experimental approaches involved different models and simplifications, results from each of them showed a fair agreement. Congruence was driven by the iterative improvements made on the boundary conditions and meshing parameters on the CFD approach, and the careful experimental design performed. The aerodynamic drag coefficient calculated by CFD was of 0.460 compared to 0.404 when calculated by experimental means, which represents a 13.8% difference or 56 drag counts.</div></div>
COVID-19 infection during the Olympic and Paralympic Games Tokyo 2020
(Elsevier BV, 2021) Tomoki Yashio; Anju Murayama; Masahiro Kami; Akihiko Ozaki; Tetsuya Tanimoto; Alfonso J. Rodríguez‐Morales
Elevating STEM Education: A Ground Station's Role in Encouraging Aerospace Science Learning
(2024) Jorge Soliz; Noelia Ayllon
Aerospace science in Bolivia faces educational chal-lenges due to economic constraints and a shortage of professionals. The Private Bolivian University has responded by establishing a specialized Ground Station (GS) for tracking and transmitting signals, with a strong emphasis on education. This GS serves as a pivotal educational hub, offering talks, workshops, and tours to both school and university students, actively promoting knowledge dissemination. Initiatives include interactive workshops and guided tours, providing students with hands-on experiences to profoundly expand their educational horizons. The GS emerges as a transformative educational resource, inspiring and actively engaging younger generations in space-related disciplines. Through a dedicated collaboration with schools, the university seeks to not only enhance educational experiences but also passionately train future professionals in the dynamic field of space science. Coordinated activities, led by GS staff, expose school students early on to exciting STEM (Science, Technology, Engineering, and Mathematics) careers, fostering the development of local talent.
Getting a Lift: The Impact of Aerial Cable Cars in La Paz, Bolivia
(2018) Sebastián Martínez; Raúl Sánchez; Patricia Yáñez
This paper studies the effects of areal cable cars on mode of transport, time use and employment in the metropolitan area of La Paz, Bolivia. Using an instrumental variables approach, we estimate local average treatment effects of cable car use for residents who use the system due to proximity to a cable car station. Results suggest that cable-car users substitute private transport in favor of public transit and experience large savings in commute time, which is reallocated toward educational and recreational activities. Users also increase self-employment activities, potentially reflecting improved access to local labor markets. The positive effects of the cable-car are driven by residents of the city of El Alto, a city with high concentration of poor and indigenous households on the high plateau bordering La Paz. The economic benefits of the cable car outweigh costs by a ratio of 1.05 to 2.16.
Influence of Inertial Properties on the Comfort of Road Vehicles
(2011) Alejandra Polanco; Luis Muñoz
<div class="section abstract"><div class="htmlview paragraph">In this paper the comfort sensitivity to the variation of the inertia parameters is studied. For the theoretical approach, two computational models that predict the comfort response of a vehicle are developed and verified. These models are used to study the effect of a change on the inertial properties of the car on its comfort response. The models are developed on a commercial multi-body package and also implementing handwritten equations with a numerical integration algorithm. The influence of the inertial properties on comfort is also experimentally studied. Both approaches use two different road patterns as input generating a roll and pitch excitation. An allowed uncertainty on the inertia properties is proposed, based on the sensitivity to those properties.</div></div>
Launch Management of a Nanosatellite for Bolivia
(Springer International Publishing, 2021) Rosalyn Puma-Guzman; Jorge Soliz
Methods of the international study on soccer at altitude 3600 m (ISA3600)
(BMJ, 2013) Christopher J. Gore; Robert J. Aughey; Pitre C. Bourdon; Laura A. Garvican‐Lewis; Rudy Soria; Jesus C Jimenez Claros; Charli Sargent; Gregory D. Roach; Martin Buchheit; Ben Simpson
Pivotal to the success of the project were the strong professional networks of the collaborators, with most exceeding 10 years, the links of several of the researchers to soccer federations, as well as the interest and support of the two head coaches.
Micropropulsión basada en combustible sólido - Caracterización y aplicación en el control de conservación de órbita en pequeños satélites
(Universidad de Los Andes, 2004) Gustavo Adolfo Ardila Rodríguez; Carole Rossi; Fernando Jiménez
This article presents the work made with the solid propellant micro-thrusters in the MIS group (Microsystems and Systems Integration) at LAAS-CNRS (Laboratory for Analysis and Architecture of Systems) located in Toulouse (France). In first place the ignition process and thrust level were characterized, then, in a second part, its applicability over the station keeping of spatial missions was evaluated, specifically missions concerning either individual or a group (constellation) of small satellites (microsatellites, nano-satellites).
MODERN DEVELOPMENTS IN RECENT HIGH SPEED AERODYNAMICS
(1963) Hongfen Chang
Neurodidáctica en ambientes virtuales de aprendizaje para la capacitación del personal de una aeronáutica
(2021) Ramiro Farias Condori Titirico
For the apprehension of knowledge by students, educational strategies are sought that guarantee better academic performance, in this sense neurodidactics is projected. Due to this, the objective of this research is to propose the implementation of neurodidactics in virtual learning environments for the training of aeronautical maintenance technical personnel at the El Alto airport, in Bolivia. The study was developed under a mixed approach (quantitative-qualitative), descriptive - propositional, non-experimental transectional design. A structured interview was applied to 2 technicians from the training program and the general director of civil aeronautics, and a survey was applied to 22 maintenance staff technicians at said airport. The main results highlight that those interviewed know about neurodidactics, but do not always apply it, although they are willing to implement it in academic training. These criteria were reflected in the opinion of those surveyed, the vast majority (41% always, 54% occasionally) consider that the lack of neurodidactic strategies is one of the factors that affect academic performance; Not very few (45% occasionally, 32% never) suggest that the teacher does not use methods focused on attention, memory, motivation and emotions; and almost all (41% occasionally and 54% never) agreed that strategies of this type are not applied to provide training. It is concluded that the implementation of neurodidactics contributes to the achievement of significant learning and the retention of knowledge, motivation and active participation of students
Pothole Identification in Flexible Pavement Using Unmanned Aerial Vehicles (UAVs)
(Springer Nature, 2021) Joaquín Humberto Aquino Rocha; Nahúm Gamalier Cayo Chileno; Silvia Natalia Azurduy Rodriguez; Alex Isaac Arrázola Brañez; José Gabriel Terán Camacho; Héctor Luis Sánchez Miranda
Review for the <i>Handbook of Aviation Neuropsychology: A Practical Guide for the Clinician</i>
(Taylor & Francis, 2025) Robert W. Elliott
Space travel in a high-altitude environment: One more step in human BioSpaceForming
(Medknow, 2018) GustavoRafael Zubieta-Calleja; NataliaMariela Zubieta-DeUrioste
BACKGROUND: Currently, space programs use sea-level pressures (760 mmHg) and normoxia (21% oxygen fraction) in space capsules. When astronauts need to go for a spacewalk, the pressure has to be reduced to 1/3 that of sea level (240 mmHg). This implies that in order to avoid decompression sickness (DCS) and acute mountain sickness (AMS), complex and time-consuming procedures need to be carried out. Furthermore, space suits have to sustain such pressure and protect them from radiation. A cooling vest is also used in order to keep the body temperature within normal values. This makes the space suits very voluminous and hence with rigid structures in order to sustain the pressure in space. Astronauts suffer, among many other complex microgravity alterations, anemia, that upon return to sea level, has to be correspondingly normalized to preflight levels. The reason that anemia presents is in part due to a lower requirement of oxygen by orthostatic muscles in microgravity. Exercise in space, reduces bone and muscle wasting. Over 200 million high-altitude residents live above 2000 m (6560 ft) of altitude and have adapted perfectly to life in the mountains. They live their life as if they were at sea level. They reproduce and practice sports, all this with a higher hematocrit. They even have proved extended longevity. METHODS: The knowledge acquired during 47 years of medical practice at high altitude, is applied to a proposal for a most efficient capsule environment for the human exploration of space. RESULTS: A cabin pressure similar to the city of La Paz, Bolivia (495 mmHg), that is, 2/3 that of sea level (760 mmHg) would not only maintain the hematocrit for reentry, but furthermore, could significantly accelerate the preparation for extravehicular activity that currently takes up several hours. High-altitude residents can tolerate lower levels of oxygen (hypoxia) providing them with an advantage of survival in oxygen poor environments. We likewise propose that a lower pressure (149 mmHg) be used in space suits, making them more flexible and thereby reducing the risks of DCS and AMS. This implies only 346 mmHg in pressure difference, from space capsule to space suit, as compared to 520 mmHg in the current methodology. CONCLUSIONS: The laws of physics in relation to pressure changes cannot be broken. However, human biology with adaptation to lower pressures and lower levels of oxygen and carbon dioxide, which is the case of high-altitude residents, can reduce the pressure gap significantly. Thereby, biology breaks the limitations of the laws of physics. Space travel will always have hypoxia as a fundamental threat, hence a hypobaric, normoxic space capsule environment results beneficial, practical, and one more step in “BioSpaceForming” of human beings.
The Grouping of Infantry Depots
(Taylor & Francis, 1937) G. G. R. Williams
The Utilization of Unmanned Aerial Vehicles (UAVs) in Cultural Heritage Buildings: A Systematic Literature Review
(Springer Science+Business Media, 2024) Joaquín Humberto Aquino Rocha; Roger Joel Rios Gonzales; Natalia Cecilia Revollar Castro; Marialaura Herrera Rosas; Alejandra Araoz Campos; Nahúm Gamalier Cayo Chileno; Alberto Casado Lordsleem Júnior