Aerospace Engineering

Thermodynamic analysis methods, based on an exergy metric, have been developed to improve system efficiency of traditional heat driven systems such as ground based power plants and aircraft propulsion systems. However, in more recent years interest in the topic has broadened to include applying these second law methods to the field of aerodynamics and complete aerospace vehicles. Work to date is based on highly simplified structures, but such a method could be shown to have benefit to the highly conservative and risk averse commercial aerospace sector. This review justifies how thermodynamic exergy analysis has the potential to facilitate a breakthrough in the optimization of aerospace vehicles based on a system of energy systems, through studying the exergy-based multidisciplinary design of future flight vehicles.

Lattice materials can be designed through their microstructure while concurrently considering fabrication feasibility. Here, we propose two types of composite lattice materials with enhanced resistance to buckling: (a) hollow lattice materials fabricated by a newly developed bottom-up assembly technique and the previously developed thermal expansion molding technique and (b) hierarchical lattice materials with foam core sandwich trusses fabricated by interlocking assembly process. The mechanical performance of sandwich structures featuring the two types of lattice cores was tested and analyzed theoretically. For hollow lattice core material, samples from two different fabrication processes were compared and both failed by nodal rupture or debonding. In contrast, hierarchical lattice structures failed by shear buckling without interfacial failure in the sandwich struts. Calculations using established analytical models indicated that the shear strength of hollow lattice cores could be...

This work involves the determination of transport coefficients and equation of state of supercritical fluids by molecular dynamics (MD) simulations on parallel computers using the Green-Kubo formulae and the virial equation of state, respectively. The MD program uses an effective Lennard-Jones potential, linked cell lists for efficient sorting of molecules, periodic boundary conditions, and a modified velocity Verlet algorithm for particle displacement. Previously, simulations had been carried out on pure argon, nitrogen and oxygen, and this has now been extended to ethylene, C^H^, at various supercritical conditions, with shear viscosity and thermal conductivity coefficients, and pressures computed for most of the conditions. The results compare well with experimental and National Institute of Standards and Technology (NIST) values.

Adhesive bonding technique is used successfully for joining the carbon fibre reinforced plastics to metals or composite structures. A good design of adhesive joint with either simple or more complex geometry requires its stress and deformation states to be known for different boundary conditions. In case the adhesive joint is subjected to thermal loads, the thermal and mechanical mismatches of the adhesive and adherends cause thermal stresses. The plate-end conditions may also result in the adhesive joint to undergo large displacements and rotations whereas the adhesive and adherends deform elastically (small strain). In this study, the thermal and geometrically non-linear stress analyses of an adhesively bonded composite tee joint with single support plus an angled reinforcement made of unidirectional CFRPs were carried out using the non-linear finite element method. In the stress analysis, the effects of the large displacements were considered using the small displacement -large displacement theory. The stress states in the plates and the adhesive layer of the tee joint configurations bonded to a rigid base and a composite plate were investigated. An initial uniform temperature distribution was attributed to the adhesive joint for a stress free state, and then variable thermal boundary conditions, i.e. air flows with different velocity and temperature were specified along the outer surfaces of the tee joints. The thermal analysis showed that a non-uniform temperature distribution occurred in the tee joints, and high heat fluxes took place along the free surfaces of the adhesive fillets at the adhesive free ends. Later, the geometrical non-linear thermal-stress analysis of the tee joint was carried out for the final temperature distribution and two edge conditions applied to the edges of the vertical and horizontal plates (HP). High stress concentrations occurred around the rounded adherend corners inside the adhesive fillets at the adhesive free ends, and along the adhesive -composite adherend interfaces due to their thermal -mechanical mismatches. The most critical joint regions were adhesive fillets subjected to high thermal gradients, the middle region of HP, the region of the vertical plate corresponding to the free end of the vertical adhesive layer -left support interface. In addition, the support length had a small effect of reducing the peak stresses at the critical adherend and adhesive locations. q

A model for predicting the refractive index of sodium iodide (NaI) aqueous solution n N I as a function of temperature T, NaI concentration c and wavelength was determined for moderate parameter variations. The equation accurately predicted the salt concentration required to match n N I to the refractive index of Pyrex n P .

The US National Aeronautics and Space Administration (NASA) Planetary Protection Office, in the Science Mission Directorate, has a long-term initiative under way in communication research and planning. The possibility of extraterrestrial life and efforts to search for evidence of it is one of NASAÕs key missions and a subject of great interest to the public. Planetary protection plays a key role in the search for signs of life elsewhere, and NASAÕs Planetary Protection Office has long recognized the importance of communications in accomplishing its goals and objectives. With solar system exploration missions advancing into the era of sample return and with the science of astrobiology changing assumptions about the nature and boundaries of life, the NASA Planetary Protection Office is expanding its communication research efforts. For the past decade, communication research sponsored by the NASA planetary protection program has focused on reaching members of the science community and addressing legal and ethical concerns. In 2003, the program broadened its communication research efforts, initiating the development of a communication strategy based on an interactive model and intended to address the needs of a broad range of external audiences. The NASA Planetary Protection Office aims to ensure that its scientific, bureaucratic, and other constituencies are fully informed about planetary protection policies and procedures and that scientists and officials involved in planetary protection are prepared to communicate with a variety of public audiences about issues relating to planetary protection. This paper describes NASAÕs ongoing planetary protection communication research, including development of a communication strategy and a risk communication plan.

This project is modeled around reducing the overall drag and lift coefficient by modifying the geometry and comprehending the underlying rootphenomenon for the variation in these drag values. The designing of models used in this project is done through SOLIDWORKS, and CFD simulation in FLUENT (ANSYS) respectively. The purpose of this project is to reduce the inefficiency caused due to aerodynamic factors of drag, lift by presenting development, design and optimization of the geometry modifications of the base model. The improvement of aerodynamic behaviour around the periphery of the model is investigated through numerical simulation. The Ahmed Reference Body having 10 degree rear slant angle has been taken as benchmark model in this paper. Simulation of variants of multifarious modifications and examination of their results is performed to find the best suited variant form (dimension) to boost the aerodynamic efficiency of the model. CFD simulations on Ahmed Body were carried out in order to serve as a benchmark for validating all the simulation results. The steady-state simulations are based on the Reynolds averaged Navier-Stokes equations, with turbulence closure provided through two-equation k-epsilon realizable models.

Hardware-in-the-loop Nanosatellite CubeSat a b s t r a c t This paper presents a study of a high rate closed-loop spin controller that uses only electromagnetic coils as actuators. The controller is able to perform spin rate control and simultaneously align the spin axis with the Earth's inertial reference frame. It is implemented, optimised and simulated for a 1-unit CubeSat ESTCube-1 to fulfil its mission requirements: spin the satellite up to 360 deg s À 1 around the z-axis and align its spin axis with the Earth's polar axis with a pointing error of less than 31. The attitude of the satellite is determined using a magnetic field vector, a Sun vector and angular velocity. It is estimated using an Unscented Kalman Filter and controlled using three electromagnetic coils. The algorithm is tested in a simulation environment that includes models of space environment and environmental disturbances, sensor and actuator emulation, attitude estimation, and a model to simulate the time delay caused by on-board calculations. In addition to the normal operation mode, analyses of reduced satellite functionality are performed: significant errors of attitude estimation due to nonoperational Sun sensors; and limited actuator functionality due to two non-operational coils. A hardware-in-the-loop test is also performed to verify on-board software.

Experiments studying cardiovascular geometries require a working fluid that matches the high index of refraction of glass and silicone, has a low viscosity, and is safe and inexpensive. A good candidate working fluid is diethyl phthalate (DEP), diluted with ethanol. Measurements were made of index of refraction and viscosity of varied dilutions at a range of temperatures, and empirical models are proposed. Material compatibility tests showed that only specific formulations of ABS, acrylic, vinyl and PVC are compatible. A silicone elastomer additionally tested negative for change in compliance with DEP exposure.

This paper shows the effect of self-shadowing on the coupled attitude-orbit dynamics of objects with high area-to-mass ratios (HAMR) in simulating standard multi layer insulation materials (MLI) as tilted single rigid sheets. Efficient and computationally fast self-shadowing methods have been developed. This includes an approximate selfshadowing method and a rapid exact self-shadowing method. Accuracy considerations are made and the effect of a chosen tessellation is shown. The coupled orbit-attitude perturbations of solar radiation pressure and Earth gravity field are taken into account. The results are compared to the attitude-orbit dynamics, when neglecting self-shadowing effects. An averaged physical shadow-map model is developed and compared to the full self-shadowing simulation. The combined effect of solar radiation pressure and selfshadowing leads to a rapid spin-up of the objects, even though they have uniform reflection properties. As a result, the observed brightness of these objects is subject to rapid changes.

Previous studies on stainless steel tubular section beam-columns have revealed shortcomings in established codified design methods. These shortcomings stem principally from inaccurate predictions of the bending and column buckling end points of the design interaction curves, where the bending moment end points are tied to the elastic or plastic moment capacities without considering strain hardening, while the column buckling end points are often overpredicted. Inaccuracies also arise due to the adopted interaction factors, which do not fully capture the structural response of the stainless steel members under combined loading. These observations prompted the present research, which is aimed at developing more efficient design rules for stainless steel tubular section beam-columns. In the presented design proposals, the deformation-based continuous strength method (CSM), allowing for strain hardening, was used to determine the bending moment capacities (i.e. the bending end points), while the column buckling strengths (i.e. the column end points) were calculated according to recently proposed buckling curves. Based on these more accurate end points, new interaction factors were derived following a comprehensive numerical simulation programme. The accuracy of the new proposals was assessed through comparisons against over 3000 Zhao, O., Gardner, L., & Young, B. (2016). Behaviour and design of stainless steel SHS and RHS beam-columns. Thin-Walled Structures, 106, 330-345. experimental and numerical results. Compared to the current design standards, the new proposal yields a higher level of accuracy and consistency in the prediction of stainless steel square and rectangular hollow section (SHS and RHS) beam-column strengths. Use of the proposed interaction factors but with the Eurocode bending moment capacities and revised column buckling strengths as the end points was also assessed and shown to result in more accurate and less scattered strength predictions than the current Eurocode provisions. The reliability of the proposals has been confirmed by means of statistical analyses according to EN 1990, demonstrating its suitability for incorporation into future revisions of international design codes for stainless steel structures.

ISHTAR or VENUS ORBITER is a mission to Venus similar to the mission Mars Express to Mars, with the use, possibly, of the same spacecraft and subsystems. This mission has been proposed to ESA for a feasibility study as a small mission (F2, F3). We shall descrii here briefly the scientific objectives of the mission, and how could be implemented. The scientific objectives of the mission are evenly distributed in three broad areas: atmospheric science, planetary interior and sut&ce, and interaction with the solar wind. Ishtar will study the surface and the atmosphere of the planet by making use of remote sensing instruments, and, if possible, by a descending meteorological balloon/lander. The model payload of the orbiter should include an Imaging Spectrometer, a Fourier Spectrometer, a Radar imaging/altimeter, a W spectrometer and a Plasma Package studying also the Energetic Neutral Atoms population resulting from the plasma interaction with the planetary atmosphere.

Sometime in the 1950s while experimenting with tip-mounted ramjet engines, Eugene M. Gluhareff built the first working pressure jet engine, a variation on the classical ramjet engine that uses an acoustically-pressurized inlet system to boost the chamber pressure at static
conditions to produce efficient thrust. Despite successful development and varied applications, Gluhareff himself never published his design methods nor any extensive information on the engines except what was necessary to sell his design. This study has compiled much of the
limited data available on Gluhareff’s engines and attempted to reverse engineer as many of its design principles as possible. It details what is known about the engine’s design and operation and works to match scaling trends with injector sizing. All sizing trends with the exception of thrust force were found to have reasonably good linear trends as represented by R-squared values. This study concludes with a discussion of past applications of the engine and the potential for future study of the pressure jet and its design principles.

In 1907 aviation pioneer Santos-Dumont had the idea of building a very light airplane. He designed and built No.19, the Demoiselle, an aircraft with a 6 meter wing span and a 24 HP engine of his own design. The Demoiselle was very successful in flying, became very popular and its development continued as No.20, No.21 and No.22 (his last airplane). The Demoiselle was one of the first aircraft that fully satisfies the criteria for physical and conceptual precursors performs the same basic function such unassisted takeoff , maneuvering and landing. The influence of the Demoiselle on design principles of light aircraft and general aviation were studied in this work, using statistical entropy. The statistical entropy is based on the probability distribution and produces satisfactory results in studies of evolutionary phenomena at the level of any population of heterogeneous entities (Saviotti, 1988 [5]). The methodology used for this work is that described by Frenken; Leydersdorff, 1999 [1]. The designs are organized by the first flight, or first operational flight as reference date. The main characteristics of the aircraft are stored into a database. The parameters chosen for analysis are: wing loading, power loading, empty weight ratio and total weight, structural efficiency, structural efficiency ratio and wing loading, global configuration, construction materials and lift coefficient. This paper assesses the critical and transition rates of diffusion and convergence of the aircraft designs. The combination of these indices in the timeline sets the schedule of technological change.

Efforts are being taken to make space missions more affordable. Reusable Launch Vehicle (RLV) is one such innovation aimed to reduce the manufacturing costs drastically. Developments are being made to make improvements on the already existing landers and also to make the full rocket reusable. This article examines the present state of the technology for reusable launch vehicles. and also aims to provide an enhancement to the already existing landing legs used on reusable launch vehicles (RLV) which can help the rocket land on uneven surfaces. This landing mechanism employs honeycomb shock absorber to absorb the energy during landing. The main purposefulness of this idea is to avoid the moment which topples the rocket during landing on uneven terrain. The paper also provides results from various analyses conducted to support the proposed idea.

It is a precious knowledge of ancient india. this script was originally composed by mahrshi BHARADWAJA, the great indian sage around 5000 BC  ,it content english transtation of some of its sanskrit stotras and shlokas.before wright brothers first aircraft was made by dr Talpade was an Indian scholar who is said to have constructed and flown an unmanned airplane in 1895 with reference of this ancient hindu sanskrit manuscript .

Separation control, by nominally two-dimensional periodic excitation, was studied experimentally by the authors and co-workers at Reynolds numbers ranging from 3 × 10 4 to 4 × 10 7 , including compressibility effects. The tests demonstrated that active control using oscillatory flow excitation can effectively delay flow separation from, and reattach separated flow to, aerodynamic surfaces at various flight conditions. At Reynolds number below 10 5 , where transition does not occur naturally and cannot be passively forced, active separation control may be the only effective method for delaying separation and generating useful lift. The essence of active separation control relies on exploiting instabilities that are inherent in the flow, generally requiring relatively small amplitude excitation. Effective excitation frequencies generate one to four vortices over the controlled region at all times, irrespective of Reynolds number, and perturbations should preferably be amplified over the region that is susceptible to separation. Periodic excitation is vastly superior to steady blowing in terms of performance benefits and eliminates abrupt flow responses, which are undesirable from a control point of view. The effects of compressibility in the absence of shocks are weak and undesirable effects accompanying separation, such as vortex-shedding and buffet, can be significantly reduced or completely eliminated. Separation resulting from shock-wave/boundary-layer interaction can be ameliorated, providing that excitation is introduced upstream of separation.  2004 Published by Elsevier SAS.

Aircraft is a brilliant man-made structure which helps us to fly over the world. At the same time, aircraft is a complex structure to be checked and maintained for the aero elasticity due to aerodynamic properties. In this paper, the fluid-structure interaction problem in super critical NASA SC(2)-0412 airfoil is discussed. The main aim of this project is to find the best performance and deformation limit of the wing on different Mach numbers. This project is completely done by numerical methods of designing the wing using CATIA and flow properties in Computational Fluid Dynamics (CFD) method. Finally, the structural analysis for deformation is analysed in ANSYS. The analytical approach of fluid-structure interaction over an Aircraft wing is complex.

Reconocer, identificar y conocer las propiedades de los materiales es muy importante en el campo de la ingeniería, ya que son ellos los que aportan las características de resistencia y estabilidad de lo que se va a diseñar. Si no se tuviese en cuenta las características de los materiales en los diseños y simplemente se construyera, existiría una amplia posibilidad de que fallaran las estructuras y/u objetos.

The paper is about preliminary sizing and analysis of a trainer aircraft wing. The main objective is to fix an appropriate
structure within the given envelope and to estimate the Gross take-off weight, wing loading, Stress distribution, low
frequency vibrational modes, take-off distance and stall velocity. Sizing is done by using classical engineering theories and
FEA packages. Skin and web are considered as shell elements. Flange, spar and stringer are considered as beam elements.
From the analysis structure has been optimally designed which satisfies the strength and stability criteria. The detailed
design of trainer aircraft wing structure is modelled using CATIA V5 R20. Then stress analysis of the wing structure is
carried out by using the finite element approach with the help of MSC NASTRAN/PATRAN to find out the safety factor of
the structure.

The latest advances in bioregenerative strategies for long-term life support in extraterrestrial outposts such as on Mars have indicated soil-based cropping as an effective approach for waste decomposition, carbon sequestration, oxygen production, and water biofiltration as compared to hydroponics and aeroponics cropping. However, it is still unknown if cropping using soil systems could be sustainable in a Martian greenhouse under a gravity of 0.38g. The most challenging aspects are linked to the gravity-induced soil water flow; because water is crucial in driving nutrient and oxygen transport in both liquid and gaseous phases, a gravitational acceleration lower than g = 9.806 m s À2 could lead to suffocation of microorganisms and roots, with concomitant emissions of toxic gases. The effect of Martian gravity on soil processes was investigated using a highly mechanistic model previously tested for terrestrial crops that couples soil hydraulics and nutrient biogeochemistry. Net leaching of NO À 3 solute, gaseous fluxes of NH 3 , CO 2 , N 2 O, NO and N 2 , depth concentrations of O 2 , CO 2 and dissolved organic carbon (DOC), and pH in the root zone were calculated for a bioregenerative cropping unit under gravitational acceleration of Earth and for its homologous on Mars, but under 0.38g. The two cropping units were treated with the same fertilizer type and rate, and with the same irrigation regime, but under different initial soil moisture content. Martian gravity reduced water and solute leaching by about 90% compared to Earth. This higher water holding capacity in soil under Martian gravity led to moisture content and nutrient concentrations that favoured the metabolism of various microbial functional groups, whose density increased by 5-10% on Mars as compared to Earth. Denitrification rates became substantially more important than on Earth and ultimately resulted in 60%, 200% and 1200% higher emissions of NO, N 2 O and N 2 gases, respectively. Similarly, O 2 and DOC were consumed more rapidly in the Martian soil and resulted in about 10% increase in CO 2 emissions. More generally, Martian cropping would require 90% less water for irrigation than on Earth, being therefore favourable for water recycling treatment; in addition, a substantially lower nutrient supply from external sources such as fertilizers would not compromise nutrient delivery to soil microorganisms, but would reduce the large N gas emissions observed in this study.

The SARA satellite was conceived as a microgravity recoverable and reusable research platform by both Brazilian Institute of Aeronautics and Space (IAE) and Space Agency (AEB). Figure 1a shows an artistic design of the platform and Fig. 1b, the planned launch vehicle of the spacecraft. The satellite was designed to carry a 55 kg payload mass, with total launch mass not exceeding 350 kg. Missions were projected to take place in circular orbits at 300 km altitude, with two-degree inclination. After completion of the microgravity experiments, up to ten days, the reentry procedure began by providing the right positioning of the satellite followed by the deboost impulse. Final deceleration took place by a high performance parachute system (Koldaev and Moraes, 1997). The spacecraft was scheduled to pass through a series of uali cation tests in ballistic ights reaching 350 km apogee and falling at about 300 km from the launch site. The system should be accelerated by a Brazilian VS-40 sounding rocket (Fig. 1b). To date, solid and liquid rocket propulsion systems were the only technological means considered for the deboost

Optical surveys have identified a class of high area-to-mass ratio (HAMR) objects in the vicinity of the Geostationary Earth Orbit (GEO) ring n . The exact origin and nature of these objects are not well known, although their proximity to the GEO belt poses a hazard to active GEO satellites. The prevalent conjecture is that many of these objects may be thermal materials shed from derelict spacecraft in 'graveyard' orbits above the GEO ring. Due to their high area-to-mass ratios and unknown attitude dynamics and material characteristics, solar radiation pressure (SRP) perturbs their orbits in ways that makes it difficult to predict their orbital trajectories over periods of time exceeding a week or less. To better understand and track these objects and infer their origins, we have made observations that allow us to determine physical characteristics that will improve the non-conservative force modeling used for orbit determination (OD) and prediction. Information on their temperatures, areas, emissivities, and albedos may be obtained from thermal infrared and visible measurements. Simultaneous observations in the thermal infrared and visible wavelengths may allow disentangling of projected area, albedo, and object emissivity. Further analysis and modeling of observational data on certain of the HAMR objects collected at the AMOS observatory 3.6 m AEOS telescope are presented. The thermal-IR spectra of these geosynchronous orbit objects acquired by the Broadband Array Spectrograph System (BASS) span wavelengths 3 to 13 mm and constitute a unique data set, providing a means of measuring object fluxes in the infrared and visible wavelengths. These, in turn, allow temperatures and emissivity-area products to be calculated, and in some cases provide information on rotation rates. We compare our observational results with the outputs of simple models, in terms of visible and infrared flux and orbital characteristics. The resulting temperatures and rotation rates are used in SRP acceleration models to demonstrate improvements in OD and prediction performance relative to models which assume default ambient temperature and static attitude dynamics. Additionally, we have the capability and plans to measure material properties with the same instrument in the lab as used at the telescope to facilitate direct comparisons.

Vent holes can be used to reduce the aerodynamic pressure loads on nonstructural elements of buildings. The analysis of these loads applied on nonstructural elements of buildings (window panes, closure panels, etc.) with vent holes, under gusty wind conditions, have been studied both experimentally and employing a theoretical model. An experimental setup based on an open circuit, closed test section, and low speed wind tunnel, designed and built at the Instituto de Microgravedad “Ignacio Da Riva” of the Universidad Politécnica de Madrid (IDR/UPM) has been used. A mechanism in the wind tunnel generates sinusoidal gusty winds inside the test section. Theoretical predictions of the pressure loads have been obtained using a mathematical model based on the mass conservation equation and polytropic law gas evolution. In the experimental setup, an air reservoir with a vent hole has been selected as a model to simulate the internal pressure loads acting on the walls of a building under a ta...

This paper describes the summary of a three-year development program for the first-stage stationary vane and rotating blade for the next generation, 1500°C class, high-efficiency gas turbine. In such a high-temperature gas turbine, the first turbine vane and blade are the most important hot parts. Full-coverage film cooling (FCFC) is adopted for the cooling scheme, and directionally solidified (DS) nickel base superalloy and thermal barrier coating (TBC) will be used to prolong the creep and thermal fatigue life. The concept of the cooling configuration, fundamental cascade test results, and material test results will be presented.

Results from the feasibility study of the "GiZero" free falling capsule are reported. GiZero is a capsule designed to perform experiments in free fall from ballooning at stratospheric altitude. It is shown that the residual gravitational disturbances inside GiZero during 20 s of free fall are smaller than 1 O-l2 g / &.

The space segment of NASA's Earth observing system (EOS) includes three series of intermediate-sized spacecraft, plus two smaller spacecraft. The EOS-AM spacecraft is the first of the intermediate-sized spacecraft. EOS-AM accommodates sensors that measure cloud and aerosol radiative properties, and that provide data to study the water and energy cycles. Scheduled for launch in the late 199Os, the EOS-AM spacecraft is designed for a 5-year mission. The spacecraft will be launched from the Western Space and Missile Center (California) into a polar, Sun-synchronous, low-Earth orbit with a 16-day repeat cycle. In its flight configuration, the spacecraft is almost 20 ft long (including instruments mounted at the fore end of the spacecraft) and 6 ft wide (in its widest dimension), has a mass of about 13,000 lbs and uses about 3000 W of electrical power. The spacecraft is compatible with the Atlas IIAS launch vehicle. EOS-AM has on-board storage for at least two orbits of science data. These data will be transmitted to the ground via the tracking and data relay satellite system (using data structures and protocols in compliance with the recommendations of the Consultative Committee for Space Data Systems). A direct downlink system to support distributed users will also be available.

A radio heliograph operating in the frequency range of 1200–1700 MHz is planned by INPE, Brazil, for investigations of time evolution of active regions, which will lead to better understanding of the physics of the flares energy release and particle acceleration, in order to suggest better criteria for the prediction of solar flares, Coronal Mass Ejections (CME), and solar terrestrial relations, such as geomagnetic storms and radio blackouts. In the first phase, the Brazilian Decimetric Array (BDA) will be a T shaped array 256 m by 144 m, consisting of 26 parabolic dish antennas of 4 m diameter. This array will produce full disk images of the sun with a spatial resolution of 3 by 5 arc minutes at 1420 MHz with a time resolution of 100 ms and sensitivity of ∼ 10 Jy. In the second phase, in addition to the compact T array there will be 6 more 7 m diameter antennas on an East-West baseline of 2560 m to obtain higher spatial resolution and better sensitivity. Thus, finally this radioheliograph will have wide field of view and couple of arcsec spatial resolution and high time resolution (100 ms).

The role of different processes which could be responsible for deceleration of the solar wind upstream of the martian bow shock is discussed. It is shown that the geometry of the foreshock strongly controls variations of the solar wind velocity. Deceleration of the solar wind was observed on three elliptical orbits when the spacecraft approached the planet inside the foreshock. Variations of the solar wind speed are not consistent with the ones expected for ring-like distribution of pickup protons. Effects related with deceleration in the foreshock and transient phenomena (Alfven waves) dominate and mask mass-loading effects if they do exist.

The intention of the NETLANDER mission is to establish for the first time a Network of stations on the surface of Mars. Four identical surface modules are equipped with science payloads dedicated to study the atmosphere and geosphere of Mars at four different landing locations spread over the two hemispheres. The mission duration will be one Martian year. The surface modules and their sensitive electronics compartments have to withstand a wide range of hostile conditions on Mars. Further constraints are given during flight, where heat can be exchanged only across small interfaces. The purpose of the NETLANDER thermal control system is to maintain the electronics and battery temperatures within a narrow band. Contrasting demands of reduced heat leaks and effective dump of surplus heat require new technologies and advanced design concepts to be satisfied under strict mass limits imposed. Recently, the first thermal test model with the original thermal equipment has been completed and tested. The model includes a high performance insulation combined with an innovative loop heat pipe system integrated into a one-to-one lander-structure. The paper describes the design and development activities as well as the ground test campaign performed in simulated Martian environment. (N. Schneider).

The INTEGRAL satellite observed the binary black hole system Cygnus X-1 on 2003 June 7-11. The source was detected up to 800 keV, its spectrum beeing compatible with a power law of photon index 2.3. In the framework of the accreting black hole phenomenology, the source was in an unusual state, probably the so-called ''intermediate state''. Using the results of the analysis performed on these INTEGRAL data, we present here the spectral properties of our observations over the whole energy range covered by the high-energy instruments on board INTEGRAL. We then compare them with those obtained from earlier observations of Cygnus X-1 performed during the INTEGRAL performance and verification phase in the fall of 2002. At that time, the source was found in the low/hard state, indicating that Cygnus X-1 underwent a transition towards a softer state in 2003 June. We discuss the spectral parameters obtained from a Comptonization model.

Measurements of the velocity and concentration in axisymmetric, turbulent, isothermal and buoyant jets have been performed with laser-Doppler velocimetry and planar and point laser-induced fluorescence to quantify the mixing enhancement achieved by periodic forcing when the jet exit has a fully-developed turbulent pipe flow, a situation less well-studied than the case of laminar initial conditions. It was found that forcing at Strouhal numbers around 0.6 enhances mixing in the developing region of the jet and this enhancement increased with increasing amplitude of excitation, consistent with results of initially-laminar jets. The initial turbulence intensity did not have any effect, but an increase in the initial lengthscale of the turbulence, controlled by a perforated plate inside the nozzle, caused faster mixing. In agreement with previous experiments, the initial conditions of the jet did not affect the far-field rate of decay, but the jet-fluid concentration there was significantly reduced by forcing due to the increased mixing during the early stages of development, an effect that can be described by a smaller virtual origin in decay laws of jet decay. These results are independent of the Froude number because the initial conditions have an influence only in the early stages where the flow is still momentum dominated.

Pulsatile action can be used to mix two streams entering a tube from two separate branches of a bifurcation at low Reynolds numbers. The pulsatile action is provided by two pinch valves, which deform flexible tubing immediately upstream of the connection. The pinch valve action is controlled using a master-slave pulse generator setup. The quality of mixing is evaluated directly by measuring the fluorescence that results from the chemical reaction of species transported in the two streams, one containing native biotin and the other, fluorescein biotin bound to streptavidin. The reaction kinetics are accounted for by normalization using fluorescence measurements on well mixed solutions at the same residence time. The results show that the pulsatile micromixer provides almost complete mixing. Furthermore, the present measurements match results obtained in a previous experiment where flow visualization and image analysis were used to measure mixing quality in a scaled-up model.

The complexity of the conceptual design of tailless aircraft can appear daunting to many. The multiple design aspects that are able to be broken out into individual problems on conventional designs, are all interrelated on the tailless aircraft configuration. This paper documents additional methods for tailless aircraft design for aspect ratios ≤ 10, and sweep angles ≤ 45°. These methods are based upon well known references that should be readily available to any designer during the conceptual design phase. Since better tools exist in the major design houses, it's assumed that a majority of conceptual designers using these methods would be homebuilt aircraft enthusiasts or modellers. Nomenclature A = wing aspect ratio c' = wing mean aerodynamic chord í µí° ¶ í µí°· í µí°¿ = wing drag coefficient due to lift í µí° ¶ í µí°¿ = wing lift coefficient í µí± ℓ í µí»¼ = airfoil section lift curve slope í µí° ¶ í µí±š = wing pitching moment coefficient í µí° ¶ í µí±š 0 = wing zero-lift pitching moment coefficient (í µí° ¶ í µí±š 0) í µí¼ƒ=0 = wing zero-lift pitching moment coefficient with zero twist ∆í µí° ¶ í µí±š 0 í µí¼ƒ = change in wing zero-lift pitching-moment coefficient due to a unit change in linear wing twist í µí± í µí±š 0 = airfoil zero-lift pitching moment coefficient í µí±‘í µí° ¶ í µí±š í µí±‘í µí° ¶ í µí°¿ = static margin (-x/c') e = Oswald span efficiency M = Mach number í µí±£ = induced-drag factor due to linear twist í µí±¤ = zero-lift drag factor due to linear twist x = distance from the center of gravity to the aerodynamic center  = compressibility factor (√1 − í µí±€ 2 í µí±“í µí±œí µí±Ÿ í µí± í µí±¢í µí±í µí± í µí±œí µí±›í µí±–í µí±) í µí¼ƒ = wing twist (positive for washin, negative for washout)  c 4 ⁄ = wing sweep measured at the ¼ chord point  = wing taper ratio í µí»¾ = compressibility correction factor to the wing zero-lift pitching moment coefficient ((í µí° ¶ í µí±š 0) í µí±€ (í µí° ¶ í µí±š 0) í µí±€=0 ⁄)

The role of transverse shear is crucial in modeling ultrasonic wave propagation in composites. The approximate plate theories have been extremely useful in providing solutions to problems involving static and dynamic loadings of uniform or laminated plates of finite dimensions. Moreover, since their simple formulations, they can also be useful for solving wave propagation problems in laminates of finite thickness and large lateral dimensions. A four-node plate bending element based on first order shear deformation theory is used in this work to predict the propagation velocity of first antisymmetric Lamb wave mode in graphite/epoxy composite plates by numerical simulation. Calculations are made using material properties obtained from a unidirectional panel via mechanical tests. For investigation, propagation along multiple directions is evaluated. Experimental and numerical results are compared at different angles of propagation and agreement between experimental and numerical approaches is found. © 2014 Elsevier Ltd.

This work provides a suboptimal continuous torque solution for controlling an underactuated spacecraft using two control inputs. A sequential submaneuver strategy is proposed. Classical quadratic penalty approaches for the control lead to jump discontinuities in the resulting control time history that can potentially excite an unwanted flexible body response. To address this operational concern, this work revises the definition for the optimal control problem by introducing a torque-rate penalty in the performance index. The significant advantage derived from this approach is that control design freedom becomes available for specifying internal control state boundary conditions, which effectively eliminates the undesirable jump discontinuities. Further optimization is achieved by introducing a positive definite weight matrix that penalizes the quadratic control term. This allows optimal tuning for the control performance where a balance is achieved between the often conflicting goals of minimizing the applied control during the maneuver and simultaneously enforcing the requirement that the resulting control be free of jump discontinuities. Numerical simulation results are presented to prove the effectiveness of the proposed method. The resulting control solutions are compared with a related approach for an underactuated system.

Abstract This paper proposes an MPC based compound flight control technique for trajectory tracking and attitude control for a ducted fan aircraft subject to different uncertainties and external disturbances. This approach aims to ensure flight robustness and achieves adequate tracking without sacrificing nominal performance while satisfying constraints under external disturbances and various uncertainties. A nonlinear ducted fan aircraft with non-minimum phase behavior is considered. By unifying a nonlinear disturbance observer with MPC, a compound flight controller is constructed. The recursive feasibility of the optimization problem for the compound controller is guaranteed, and the closed-loop stability is ensured. To demonstrate the effectiveness of the developed scheme, a robust MPC framework is employed for comparative analysis. Finally, numerical simulations and discussions are provided to corroborate the performance of both compound strategies.

The authors aimed with this work to study the "vortex" on the wing tip of a "Blended Wing Body" aircraft using computational tools available that use the methods of"finite element" and "Computational Fluid Dynamics". The purpose of it is to reduce the vortex intensity, improving stability, reducing the "induced drag" and promoting less turbulence in the aircraft. This new aircraft configuration is a little different from the ones we have today. Blend Wing Body aircrafts fuselage and wings are one body, changing a loot o fight characteristics.

It is well known that certain fluids are birefringent and when flows are viewed in polarised light interference fringes are observed. The fringes are caused by a phase shift in the light passing through the fluid and are proportional to the integral of the maximum shear strains in the fluid. In order to understand what is happening within the flow and overcome the difficulties due to this integration of analysing three dimensional flows, additional computational or experimental information is needed. In this work, a commercially available computer code (Fluent) is used for the first time to model the flows. The flow data are then exported to a spreadsheet where the shear rates are integrated across the field and then banded for graphical output. The results from this are then compared to results generated from birefringent flow experiments and the agreement is found to be good since the modelled fringes show the same patterns as those in the experiment. This novel use of computational and experimental techniques together will allow quantitative analysis of three dimensional flows in the future. 2 Currently, there are still a lot of empirical variables involved in fitting the computational fringes to the experiment, but the results of this preliminary study show that this is a promising approach to this type of problem.