The Solar Wind interactions with Lunar Magnetic Anomalies: A case study of the Chang’E-2 plasma data near the Serenitatis antipode

In this paper, we present the first and preliminary results on the near-Moon plasma environment, based on the spectrogram data obtained with the Solar Wind Ion Detector (SWID) onboard Chang’E-2 from four lunar orbits on 10–11 Oct 2010. These orbits, at a constant altitude of ∼100 km, approach gradually the Lunar Magnetic Anomaly (LMA) at the Serenitatis antipode. The data reveal tentatively a region with decrement in proton density and enhancement in temperature. The near coincidence of this region with the Serenitatis antipode probably suggests the presence of a minimagnetosphere associated with the LMA, which effectively shields and heats the incident Solar Wind (SW) protons.     

Observation of fast variations of the helium-ion abundance in the solar wind

This paper describes the results of studying the helium component of the solar-wind ion-flux measurement by the BMSW instrument on the Spektr-R satellite with a time resolution of 3 s. In contrast to most previous works that presented values averaged over large (hourly average or daily average) intervals, we have shown that the relative helium-ion abundance in the solar wind experiences considerable (by a few percent and even 10%) variations on such short intervals as 10 seconds or even several seconds.     

Chemical mapping of proterozoic organic matter at submicron spatial resolution

A NanoSIMS ion microprobe was used to map the submicron-scale distributions of carbon, nitrogen, sulfur, silicon, and oxygen in organic microfossils and laminae in a thin section of the approximately 0.85 billion year old Bitter Springs Formation of Australia. The data provide clues about the original chemistry of the microfossils, the silicification process, and the biosignatures of specific microorganisms and microbial communities. Chemical maps of fossil unicells and filaments revealed distinct wall- and sheath-like structures enriched in C, N, and S, consistent with their accepted biological origin. Surprisingly, organic laminae, previously considered to be amorphous, also exhibited filamentous and apparently compressed spheroidal structures defined by strong enrichments in C, N, and S. By analogy to NanoSIMS data from the well-preserved microfossils, these structures were interpreted as being of biological origin, most likely representing densely packed remnants of microbial mats. Given that the preponderance of organic matter in Precambrian sediments is similarly "amorphous," our findings indicate that a re-evaluation of ancient specimens via in situ structural, chemical, and isotopic study is warranted. Our analyses have led us to propose new criteria for assessing the biogenicity of problematic kerogenous materials, and, thus, these criteria can be applied to assessments of poorly preserved or fragmentary organic residues in early Archean sediments and any that might occur in meteorites or other extraterrestrial samples.     

Impact of reduced frequency on the time lag in pressure distribution over a supercritical airfoil in a pitch-pause-return motion

Effects of reduced frequency, stop angle, and pause duration have been studied on a thin supercritical airfoil undergoing a pitch-pause-return motion, which is one of the classic maneuvers introduced by the AIAA Fluid Dynamics Technical Committee. Experiments were conducted in a low-speed wind tunnel at both a constant mean angle of attack and an oscillation amplitude with a reduced frequency ranging from 0.01 to 0.12. The desired stop angles of the airfoil were set to occur during the upstroke motion. The unsteady pressure distribution on the airfoil was measured for below, near, and beyond static stall conditions. Results showed that the reduced frequency and stop angle were the dominant contributors to the time lag in the flowfield. For stop angles in both below- and post-stall regions, the time for the flowfield to reach its steady state conditions, known as the time lag, decreased as the reduced frequency was increased. However, in the static-stall region and for a certain value of reduced frequency, a resonance phenomenon was observed, and a minimum time lag was achieved. The pressure distribution in this condition was shown to be highly influenced by this phenomenon.     

Old tail lobes effect on the solar-wind – Magnetosphere energy transport for the 27 August 2001 substorm

The magnetic flux of tail lobes Ψ is divided in two parts of comparable values Ψ₁ and Ψ₀₂, with the first that appears during substorm and the second, observed before substorm start. The first was named “new magnetic flux”, the second – “old magnetic flux”. The first, Ψ₁, is known to play a definitive role in the energy transport from the solar wind into the magnetosphere-ionosphere-atmosphere system, but the role of Ψ₀₂ in this transport is not well known. From the 27 August 2001 substorm data we study the involvement in the above transport process of the old flux Ψ₀₂. This involvement is observed in the polar cap (PC) area, which existed prior to the substorm and is called respectively “the old PC”. In this study, as distinct from earlier works, we use the balance equation of the energy stored in magnetosphere and energy consumed. Activation of the old PC magnetic flux Ψ₀₂ was found to increase the energy input by ∼85% in the event under consideration.     

Physical modeling of electromagnetic interferences in the unmanned aerial vehicle in the case of high-voltage transmission line impact

A technique has been developed for studying the interference resistance of electronic systems for unmanned aerial vehicles based on physical modeling The paper proposes mathematical models, a scheme of a test stand and examples of parameter calculation for physical modeling of electromagnetic interferences in communication links of the unmanned aerial vehicle in the case of electromagnetic fields of high-voltage transmission lines interference. Examples demonstrating successful implementation of physical modeling for similar tasks ascertain the feasibility of this approach.     

The OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS): Spectral Maps of the Asteroid Bennu

The OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) is a point spectrometer covering the spectral range of 0.4 to 4.3 microns (25,000–2300 cm^?1). Its primary purpose is to map the surface composition of the asteroid Bennu, the target asteroid of the OSIRIS-REx asteroid sample return mission. The information it returns will help guide the selection of the sample site. It will also provide global context for the sample and high spatial resolution spectra that can be related to spatially unresolved terrestrial observations of asteroids. It is a compact, low-mass (17.8 kg), power efficient (8.8 W average), and robust instrument with the sensitivity needed to detect a 5% spectral absorption feature on a very dark surface (3% reflectance) in the inner solar system (0.89–1.35 AU). It, in combination with the other instruments on the OSIRIS-REx Mission, will provide an unprecedented view of an asteroid’s surface.     

Determination of ingredient composition of atmospheric emissions of the turbojet engine combustion gases by the fine-structure spectroscopy

The application of the method of absorbing fine-structure spectroscopy to determine the composition of ingredient emissions of products of combustion of the turbojet engine. Applied for research of ingredient composition of complex spectrophotometric instrumentation provides a measurement of the concentration of the various ingredients in the products of combustion to limit sensitivity of 1–10 ppm. The technology of measurement and processing of the data of spectrometric measurements are discussed. The results of measurements of the ingredient composition released into the atmosphere of the combustion products of the turbojet engine are analysed.     

Formation of required transfer zero location in the multiconnected dynamic system

A method for providing the required location of a transfer zero set in the linear multiconnected dynamic system with an equal number of inputs and outputs is considered.     

Three-phase rectifiers that apply optimal current injection

A class of current injection based three-phase high power factor rectifiers is proposed. Low distortion of the input currents and high power factor are obtained applying near optimal current injection. The optimal current injection is discussed, and requirements it imposes to the current injection network are derived. A class of simple current injection networks that provide near optimal current injection, consisting of a transformer, two capacitors, and a number of resistors or resistance emulators is proposed. The power processed by the resistors or resistance emulators is shown to be 8.81% of the input power. Design of the current injection network is discussed, and dependence of the input current distortion on capacitance of the applied capacitors is analyzed. Volt-ampere rating of the transformer is shown to be only 0.16% of the input power. Effects caused by the output current ripple are studied, and a method for their compensation is proposed. Analytical results are experimentally verified. Switching resistance emulation is discussed and its feasibility is experimentally demonstrated