Atmospheric Systems
Mostrando 1-12 de 125 artigos, teses e dissertações.
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1. MGF Methods for Fixed and Gain Saturated Optically Preamplified FSO Links Impaired by Misalignments and Atmospheric Turbulence
Abstract The Gaussian approximation is commonly used to evaluate the performance of free space optical communication systems. However, other performance evaluation methods such as the saddle point approximation, Chernoff bound and the modified Chernoff bound have also been used. This paper investigates the performance of fixed and gain saturated optically pr
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Key Terrestrial and Space Environment Sources
ABSTRACT Natural (Terrestrial & Space) Environment (NE) phenomena play a significant role in the design and flight of aerospace vehicles and in the integrity of the associated aerospace systems and structures. Both the terrestrial environment (0-90 km altitude) and the space environment (Earth orbital altitudes) parameters and their engineering application p
J. Aerosp. Technol. Manag.. Publicado em: 17/01/2020
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3. DEEP EUTECTIC SOLVENTS BASED ON BETAINE AND PROPYLENE GLYCOL AS POTENTIAL DENITRIFICATION AGENTS: A LIQUID-LIQUID EQUILIBRIUM STUDY
Abstract Two deep eutectic solvents (DES) based on betaine (B) and propylene glycol (PG) in molar ratios of 1:4 and 1:5 were prepared and their physico-chemical properties were determined. Liquid-liquid equilibria at 298.15 K and atmospheric pressure were determined for 13 quasi-three-component systems with a hydrocarbon (n-hexane, n-heptane, i-octane or tol
Braz. J. Chem. Eng.. Publicado em: 13/01/2020
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4. EFFECT OF CYCLOPENTANE HYDRATES ON THE STABILITY OF DODAC AND AOT STRUCTURES
Abstract Hydrates are crystalline structures formed by water and substances with low molar mass molecules. Hydrate formation can occur during oil production when oil, gas and water flow through the same lines in conditions of high pressure and low temperatures. The deposition of hydrate crystals in production lines can severely jeopardize the safety of oper
Braz. J. Chem. Eng.. Publicado em: 13/01/2020
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5. How increased atmospheric carbon dioxide and ‘The Law of the Minimum’ are contributing to environmental obesity
Resumo Justus von Liebig observou que era possível aumentar a produção agrícola adicionando pequenas quantidades de nitrogênio (N), fósforo (P) e potássio (K) aos solos. Essa descoberta levou a mais recente revolução agrícola. Contudo, uma vez que a maioria das plantas e microrganismos podem ser não-homeostáticos em relação a composição quím
Acta Limnol. Bras.. Publicado em: 28/11/2019
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6. The Role of Terrestrial and Space Environments in Launch Vehicle Development
ABSTRACT: Natural (Terrestrial & Space) Environment (NE) phenomena play a significant role in the design and flight of aerospace vehicles and in the integrity of the associated aerospace systems and structures. Natural environmental design criteria guidelines described here are based on measurements and modeling of atmospheric and climatic phenomena relative
J. Aerosp. Technol. Manag.. Publicado em: 04/11/2019
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7. KLOBUCHAR AND NEQUICK G IONOSPHERIC MODELS COMPARISON FOR MULTI-GNSS SINGLE-FREQUENCY CODE POINT POSITIONING IN THE BRAZILIAN REGION
Abstract One of the main error sources in GNSS positioning comes from the ionosphere, an atmospheric layer that stays in the signal path between the satellite and the receiver. For single frequency positioning, the ionospheric effects can be minimized by using an ionospheric model e.g. Klobuchar or NeQuick G. These models are respectively associated to GPS a
Bol. Ciênc. Geod.. Publicado em: 14/10/2019
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8. Uso de VANT para Prospecção Eólica em Sistemas Aquáticos: Desenho Amostral e Avanços Instrumentais
Resumo O Projeto “uso de VANT para prospecção eólica em sistemas aquáticos” consistiu num esforço multi-instrumental e multi-institucional para estudar a camada limite atmosférica influenciada por extensos corpos d’água e pelas feições do entorno como colinas, rampas e mudanças abruptas de rugosidade. Dois trabalhos de campo foram conduzidos
Rev. bras. meteorol.. Publicado em: 05/08/2019
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9. ÉTERES DIFENÍLICOS POLIBROMADOS (PBDE) COMO CONTAMINANTES PERSISTENTES: OCORRÊNCIA, COMPORTAMENTO NO AMBIENTE E ESTRATÉGIAS ANALÍTICAS
Flame retardants are substances mixed with numerous materials to inhibit the combustion process, reducing risks and damages caused by fires. Among these substances, polybrominated diphenyl ethers (PBDEs) have been widely used for decades due to their low cost and high efficiency. However, since they are mixed and not chemically bonded to the materials, PBDEs
Quím. Nova. Publicado em: 2018-07
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10. A model for implementation of HACCP system for prevention and control of mycotoxins during the production of red dried chili pepper
Abstract Hazard analysis and critical control points (HACCP) is a process control system describes the potential hazards during food production flow chart. In contrast to the conventional way of ensuring product safety by end-product testing, HACCP establishes control systems, focuses mainly on preventive measures. Quality of red dried chili pepper (RDCP) sh
Food Sci. Technol. Publicado em: 13/03/2017
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11. Comparison of In-Flight Measured and Computed Aeroelastic Damping: Modal Identification Procedures and Modeling Approaches
ABSTRACT The Operational Modal Analysis technique is a methodology very often applied for the identification of dynamic systems when the input signal is unknown. The applied methodology is based on a technique to estimate the Frequency Response Functions and extract the modal parameters using only the structural dynamic response data, without assuming the kn
J. Aerosp. Technol. Manag.. Publicado em: 2016-06
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12. Preliminary Study about the Origin of Trace Elements in the Atmospheric Deposition in Two Brazilian Subtropical Estuaries
The atmospheric deposition of dissolved trace elements was investigated in two subtropical estuarine systems, located on the coast of Paraná, Southeast Brazil. The samples (n = 91) were collected in three periods, from May to September 2010, in four different areas. Trace elements concentrations (Al, Fe, Zn, Mn, Ba, Ca, Mo, V, As, Cu, Co, Ni, Cr and Pb) wer
J. Braz. Chem. Soc.. Publicado em: 2016-04