Aerodynamical Properties Research Articles

Origin of Isotopic Diversity among Carbonaceous Chondrites

Carbonaceous chondrites are some of the most primitive meteorites and derive from planetesimals that formed a few million years after the beginning of the solar system. Here, using new and previously published Cr, Ti, and Te isotopic data, we show that carbonaceous chondrites exhibit correlated isotopic variations that can be accounted for by mixing among three major constituents having distinct isotopic compositions, namely refractory inclusions, chondrules, and CI chondrite-like matrix. The abundances of refractory inclusions and chondrules are coupled and systematically decrease with increasing amount of matrix. We propose that these correlated abundance variations reflect trapping of chondrule precursors, including refractory inclusions, in a pressure maximum in the disk, which is likely related to the water ice line and the ultimate formation location of Jupiter. The variable abundance of refractory inclusions/chondrules relative to matrix is the result of their distinct aerodynamical properties resulting in differential delivery rates and their preferential incorporation into chondrite parent bodies during the streaming instability, consistent with the early formation of matrix-poor and the later accretion of matrix-rich carbonaceous chondrites. Our results suggest that chondrules formed locally from isotopically heterogeneous dust aggregates, which themselves derive from a wide area of the disk, implying that dust enrichment in a pressure trap was an important step to facilitate the accretion of carbonaceous chondrite parent bodies or, more generally, planetesimals in the outer solar system.

Moisture‐dependent engineering properties of arugula seed relevant in mechanical processing and bulk handling

AbstractKnowledge of the engineering properties of seeds, grains, nuts, kernels, and fruits is vital in the design of planting, harvesting, and postharvesting machines. This study investigates moisture‐dependent geometrical, gravimetrical, frictional, rheological, and aerodynamical properties of arugula seed. The length, width, and thickness of the seed distributions were modeled by the Normal, Log‐normal, and Weibull probability density functions. In the moisture ranges of 4.68–20.50%, the major, intermediate, and minor seed dimensions increased from 2.01 to 2.35 mm, 1.60 to 1.98 mm, and 1.17 to 1.33 mm, respectively. The results indicated that Log‐normal distribution had the best performance in most cases. Values of 1,000‐seed mass, bulk density, particle density, and porosity ranged between 1.33 to 1.77 g, 703.07 to 644.37 kg m−3, 1,160 to 1,392 kg m−3, and 39.39 to 53.71% as in the above moisture ranges. The filling and emptying angles of repose increased from 29.21° to 34.78° and 37.95° to 39.75°, respectively, as the moisture content increased. Incremental trends were observed for terminal velocity in water and air and residual stress during relaxation tests. Decreasing trends were observed for drag coefficient, modulus of elasticity, maximum contact stress, toughness, hardness, rupture force, and reduced stress during relaxation tests.Practical ApplicationsArugula (Eruca vesicaria L. or Eruca sativa Mill L.) is a popular worldwide vegetable. Besides consuming its leaves as a vegetable, the oil extracted from its seeds has industrial uses. This study investigated properties of arugula seeds with varying moisture contents with a view to understand their relevance in mechanical processing and bulk handling. The results presented in the current work would contribute to designing the metering devices (distributors), sorters, separators, cleaners, transportation systems, conveyors, oil extractors, etc.

Formulation and In Vitro and In Silico Characterization of "Nano-in-Micro" Dry Powder Inhalers Containing Meloxicam.

Pulmonary delivery has high bioavailability, a large surface area for absorption, and limited drug degradation. Particle engineering is important to develop inhalable formulations to improve the therapeutic effect. In our work, the poorly water-soluble meloxicam (MX) was used as an active ingredient, which could be useful for the treatment of non-small cell lung cancer, cystic fibrosis, and chronic obstructive pulmonary disease. We aimed to produce inhalable “nano-in-micro” dry powder inhalers (DPIs) containing MX and additives (poly-vinyl-alcohol, leucine). We targeted the respiratory zone with the microcomposites and reached a higher drug concentration with the nanonized active ingredient. We did the following investigations: particle size analysis, morphology, density, interparticular interactions, crystallinity, in vitro dissolution, in vitro permeability, in vitro aerodynamics (Andersen cascade impactor), and in silico aerodynamics (stochastic lung model). We worked out a preparation method by combining wet milling and spray-drying. We produced spherical, 3–4 µm sized particles built up by MX nanoparticles. The increased surface area and amorphization improved the dissolution and diffusion of the MX. The formulations showed appropriate aerodynamical properties: 1.5–2.4 µm MMAD and 72–76% fine particle fraction (FPF) values. The in silico measurements proved the deposition in the deeper airways. The samples were suitable for the treatment of local lung diseases.

Physical and Aerodynamic Characterization of Particle Clusters at Sakurajima Volcano (Japan)

The process of particle aggregation significantly affects ash settling dynamics associated with volcanic explosive eruptions. Several experiments have been carried out to investigate the physics of ash aggregation and dedicated numerical schemes have been developed to produce more accurate forecasting of ash dispersal and sedimentation. However, numerical description of particle aggregation is complicated by the lack of complete datasets on natural samples required for model validation and calibration. Here we present a first comprehensive dataset for the internal structure, aerodynamical properties (e.g., size, density, terminal velocity) and grain size of constituting particles of a variety of aggregate types collected in the natural laboratory of Sakurajima Volcano (Japan). Even though the described particle clusters represent the most common types of aggregates associated with ash-rich fallouts, they are of difficult characterization due to the very low potential of preservation in tephra-fallout deposits. Properties were, therefore, derived based on a combination of high-resolution-high-speed videos of tephra fallout, scanning electron microscope analysis of aggregates collected on adhesive paper and analysis of tephra samples collected in dedicated trays. Three main types of particle clusters were recognized and quantitively characterized: cored clusters (PC3), coated particles (PC2), and ash clusters (PC1) (in order of abundance). A wide range of terminal velocities (0.5–4 m/s) has been observed for these aggregates, with most values varying between 1 and 2 m/s, while aggregate size varies between 200 and 1,200 µm. PC1, PC2, and PC3 have densities between 250 and 500, 1,500 and 2,000, and 500 and 1,500 kg/m3, respectively. The size of the aggregate core, where present, varies between 200 and 750 µm and increases with aggregate size. Grain size of tephra samples was deconvoluted into a fine and a coarse Gaussian subpopulation, well correlated with the grain size of shells and of the internal cores of aggregates, respectively. This aspect, together with the revealed abundance of PC3 aggregates, reconciles the presence of a large amount of fine ash (aggregate shells) with coarse ash (aggregate cores) and better explains the grain size distribution bimodality, the high settling velocity with respect to typical PC1 velocities and the low settling velocities of large aggregates with respect to typical PC2 velocity. Furthermore, ash forming the aggregates was shown to be always finer than 45 µm, confirming the key role played by aggregation processes in fine ash deposition at Sakurajima.

Large Eddy Simulation of a Turbulent Spray Jet Flame Using Filtered Tabulated Chemistry

This work presents Large Eddy Simulations of the unconfined CORIA Rouen Spray Burner, fed with liquid n-heptane and air. Turbulent combustion modeling is based on the Filtered TAbulated Chemistry model for LES (F-TACLES) formalism, designed to capture the propagation speed of turbulent stratified flames. Initially dedicated to gaseous combustion, the filtered flamelet model is challenged for the first time in a turbulent spray flame configuration. Two meshes are employed. The finest grid, where both flame thickness and wrinkling are resolved, aims to challenge the chemistry tabulation procedure. At the opposite the coarse mesh does not allow full resolution of the flame thickness and exhibits significant unresolved contributions of subgrid scale flame wrinkling. Both LES solutions are extensively compared against experimental data. For both nonreacting and reacting conditions, the flow and spray aerodynamical properties are well captured by the two simulations. More interesting, the LES predicts accurately the flame lift-off height for both fine and coarse grid conditions. It confirms that the modeling methodology is able to capture the filtered turbulent flame propagation speed in a two-phase flow environment and within grid conditions representative of practical applications. Differences, observed for the droplet temperature, seem related to the evaporation model assumptions.

Prediction of plywood deformation under the impact of windborne debris using Taguchi method

Windstorms and tornados can cause severe damages to different structure types regardless the materials they have been made of. These damages are caused both by the extreme wind velocity and any flying debris within the wind field. Windborne debris is classified based on shape and aerodynamical properties into three types: compact, rod, and plate-like debris. According to both American and Australian Standards, the performance of any structural element is to be tested under the impact of rod-like debris. Plywood is used globally to create both structural and non-structural elements such as doors and window shutters, and thus, in this study, a numerical simulation of rod-like debris was conducted using LS-DYNA to study the effect of debris impact velocity on the deformation of a plywood plate. In this way, the effect of the plate thickness and modulus of elasticity on the deformation were also investigated. Taguchi Method was adopted to make the simulation more robust and reduce the required computational time and costs. The results showed that as the debris impact velocity increased, both the deformation of the plywood plate at penetration and the residual kinetic energy of the debris increased. However, for the same plate thickness and debris impact velocity, as the modulus of elasticity increased, the deformation of the plate at the point of penetration decreased.

Stability test of novel combined formulated dry powder inhalation system containing antibiotic: physical characterization and in vitro–in silico lung deposition results

Objective: The aim was to study the stability of dry powder inhaler (DPI) formulations containing antibiotic with different preparation ways – carrier-based, carrier-free, and novel combined formulation – and thereby to compare their physicochemical and in vitro–in silico aerodynamical properties before and after storage. Presenting a novel combined technology in the field of DPI formulation including the carrier-based and carrier-free methods, it is the most important reason to introduce this stable formulation for the further development of DPIs.Methods: The structure, the residual solvent content, the interparticle interactions, the particle size distribution and the morphology of the samples were studied. The aerodynamic values were determined based on the cascade impactor in vitro lung model. We tested the in silico behavior of the novel combined formulated samples before and during storage.Results: The physical measurements showed that the novel combined formulated sample was the most favorable. It was found that thanks to the formulation technique and the use of magnesium stearate (MgSt) has a beneficial effect on the stability compared with the carrier-based formulation without MgSt and carrier-free formulations. The results of in vitro and in silico lung models were consistent with the physical results, so the highest deposition was found for the novel combined formulated sample during the storage.Conclusions: It can be established that after the storage a novel combined formulated DPI contained amorphous drug to have around 2.5 μm mass median aerodynamic diameter and nearly 50% fine particle fraction predicted high lung deposition in silico also.

Post harvest processing, cooking and textural properties of horse gram (Mycrotyloma uniflorum) varieties

Four Horse gram varieties GPM-6, Hebbal Hurrali-1, BHK and Paiyur-2 from southern region of India were studied for various physical, mechanical, aerodynamical and cooking properties. These parameters were often utilized to design and develop more economical and efficient agricultural produce processing machinery and equipment especially during post-harvest operations and for consumer accepatance. Length, width, thickness and volume of the horse gram varieties were in the range of 5.44–6.01, 3.99–4.09, 2.21–2.29 and 25.57–29.48mm3, respectively. Moisture content, thousand kernel weight, bulk density, true density, and porosity were in the range of 10.13–11.63%, 30.32–32.98 g, 810–901, 1250–1426 kg/m3, 34.92–36.87% respectively. Angle of repose ranged from 22.73 to 25.42°. The shape of individual grain was ellipsoidal. The experimental terminal velocity was greater for all varieties in comparison to its theoretical terminal velocity. Results showed that the soaking prior to cooking leads to reduction in cooking time for the horse gram varieties. A strong significant negative correlation of soaking duration with cooking time (r = −0.912, p < 0.01) was observed. Horse gram cultivars with low seed weight had higher cooking time and higher water absorption capacity. Among the varieties studied, GPM-6 was found to be the best followed by Hebbal Hurrali in terms of lower cooking time, higher water absorption of soaked seeds and low hardness of cooked seeds.

DUST DIFFUSION AND SETTLING IN THE PRESENCE OF COLLISIONS: TRAPPING (SUB)MICRON GRAINS IN THE MIDPLANE

ABSTRACT In protoplanetary disks, the distribution and abundance of small (sub)micron grains are important for a range of physical and chemical processes. For example, they dominate the optical depth at short wavelengths and their surfaces are the sites of many important chemical reactions, such as the formation of water. Based on their aerodynamical properties (i.e., their strong dynamical coupling with the surrounding gas) it is often assumed that these small grains are well-mixed with the gas. Our goal is to study the vertical (re)distribution of grains taking into account settling, turbulent diffusion, and collisions with other dust grains. Assuming a fragmentation-limited background dust population, we developed a Monte Carlo approach that follows single monomers as they move through a vertical column of gas and become incorporated in different aggregates as they undergo sticking and fragmenting collisions. We find that (sub)micron grains are not necessarily well-mixed vertically, but can become trapped in a thin layer with a scale height that is significantly smaller than that of the gas. This collisional trapping occurs when the timescale for diffusion is comparable to or longer than the collision timescale in the midplane and its effect is strongest when the most massive particles in the size distribution show significant settling. Based on simulations and analytical considerations, we conclude that for typical dust-to-gas ratios and turbulence levels, the collisional trapping of small grains should be a relatively common phenomenon. The absence of trapping could then indicate a low dust-to-gas ratio, possibly because a large portion of the dust mass has been removed through radial drift or is locked up in planetesimals.

Protoplanetary dust porosity and FU Orionis outbursts: Solving the mystery of Earth’s missing volatiles

The Earth is known to be depleted in volatile lithophile elements in a fashion that defies easy explanation. We resolve this anomaly with a model that combines the porosity of collisionally grown dust grains in protoplanetary disks with heating from FU Orionis events that dramatically raise protoplanetary disk temperatures. The heating from an FU Orionis event alters the aerodynamical properties of the dust while evaporating the volatiles. This causes the dust to settle, abandoning those volatiles. The success of this model in explaining the elemental composition of the Earth is a strong argument in favor of highly porous collisionally grown dust grains in protoplanetary disks outside our Solar System. Further, it demonstrates how thermal (or condensation based) alterations of dust porosity, and hence aerodynamics, can be a strong factor in planet formation, leading to the onset of rapid gravitational instabilities in the dust disk and the subsequent collapse that forms planetesimals.

Determination of Ventilation Channels In Urban Area: A Case Study of Wrocław (Poland)

Urban areas are among the roughest landscapes in the Earth and its aerodynamical properties are responsible for a lot of processes and phenomena of urban climate, such as surface drag and pollutant dispersion. These properties can be quantitatively expressed by various parameters, with zero plane displacement height (z d) and roughness length (z 0) as the most frequently applied. Based on remotely gathered (LIDAR scan) height data and morphometric methods of roughness calculations, the comprehensive procedure to determine ventilation channels in urban area is proposed and implemented on the example from Wroclaw, Poland. Morphometric analysis of urban structure allowed establishing a proper database of aerodynamic parameters of the city. Then a series of maps of the city showing the distribution of two roughness parameters were prepared. GIS tools were used to carry out the analysis of roughness data, assuming various directions of wind flow. It enabled to determine the locations of potential ventilation paths in the city which, if combined, form large ventilation channels. They may have a significant role in improving air quality and be a valuable source of information for local government responsible for the appropriate development of the city.

Several observation about aerodynamical properties of addition

Several observation about aerodynamical properties of addition

Aerodynamical, Immunological and Pharmacological Properties of the Anticancer Antibody Cetuximab Following Nebulization

Despite an increasing interest in the use of inhalation for local delivery of molecules for respiratory diseases and systemic disorders, methods to deliver therapy through airways has received little attention for lung cancer treatment. However, inhalation of anticancer drugs is an attractive alternative route to systemic administration which results in limited concentration of the medication in the lungs, and triggers whole-body toxicity. In this study, we investigated the feasibility of nebulization for therapeutic antibodies, a new class of fully-approved anticancer drugs in oncology medicine. Cetuximab, a chimeric IgG1 targeting the epidermal growth factor receptor (EGFR), was nebulized using three types of delivery devices: a jet nebulizer PARI LC+, a mesh nebulizer AeronebPro and an ultrasonic nebulizer SYST'AM LS290. Aerosol size distribution was measured using a cascade impactor and aerosol droplets were observed under optical microscopy. The immunological and pharmacological properties of cetuximab were evaluated following nebulization using A431 cells. The aerosol particle clouds generated with the three nebulizers displayed similar aerodynamical characteristics, but the IgG formed aggregates in liquid phase following nebulization with both the jet and ultrasonic devices. Flow cytometry analyses and assays of EGFR-phosphorylation and cell growth inhibitions on A431 demonstrated that both the mesh and the jet nebulizers preserved the binding affinity to EGFR and the inhibitory activities of cetuximab. Altogether, our results indicate that cetuximab resists the physical constraints of nebulization. Thus, airway delivery represents a promising alternative to systemic administration for local delivery of therapeutic antibodies in lung cancer treatment.

A method to determine the atmospheric temperature profile from in situ pressure data: Application to Titan

We have developed a new method to analyse in situ observations of atmospheric variables of state: the reconstruction of the vertical temperature profile from pressure measurements accompanied by rough knowledge of the atmospheric composition and the aerodynamical response properties of the descent vehicle. We can use the method to construct the temperature profile when no direct measurements are available, as well as to analyse the consistency between data from different instruments. We applied the method to the Huygens measurements of Titan's atmosphere, determining the aerodynamical drag properties from radar altimeter data. We discovered that the temperature profile computed in this manner differs from the profile from the temperature sensor (TEM) of the probe by up to 5% in the altitude range of 0–60 km, and up to 10% at higher altitudes due to increased noise. The method gives a tropopause altitude of about 50 km and a surface temperature of about 98 K, in contrast to the TEM temperature measurements. Our error analysis shows that these differences are caused by the known discrepancy in the Huygens altimeter data, with the estimates made by the reconstruction algorithm contributing only 1–2% of error.

Asymptotic behaviour of solutions to cable stayed bridge equations

Asymptotic behaviour of solutions to the nonlinear variational equations of the two basic types of cable stayed bridges is studied. The equations describe vertical and torsional oscillations of the center span, which is the part of road bed between pylons. Due to damping, amplitude and velocity of oscillations remain bounded if wind force is bounded as well. Moreover, the solution to the nonlinear equations converges to the solution of the steady state problem if wind drops. If the center span has certain aerodynamical properties and the initial state is near to the solution of the steady state problem, then the solution converges to the steady state solution even if the forces representing wind do not vanish.

Shape optimization for radar cross sections by a gradient method

AbstractA gradient method for optimization of shape and materials for radar cross section (RCS) reduction is derived from Maxwell's equations. The method uses the adjoint problem and finds the derivatives of the RCS with respect to all design parameters from a single solution of the scattering problem. The method is tested in two‐dimensional test problems to minimize the RCS in specified angular intervals at a single frequency, and finds configurations with strongly reduced RCS in a small number of iterations. In the absence of other constraints, the optimal shapes of perfectly electrically conducting (PEC) scatterers have sharp corners pointing in the directions where the RCS is minimized and shapes optimized at a single or small number of frequencies exhibit corrugations with about half the wavelength of the incident wave. The corrugations can be suppressed by means of penalty functions, and this gives only moderate increases of the RCS. After such regularization, the optimal shapes agree well with expectations from geometrical optics; they have almost flat surfaces whose normals lie outside the intervals chosen for RCS optimization, and sharp edges at locations where the surface normal points into the intervals in which the RCS is minimized. Shape optimization of PEC wing profiles aiming at both good aerodynamical properties and low RCS show give conflicting requirements on the shape. Copyright © 2004 John Wiley &amp; Sons, Ltd.

High-performance road-vehicle optimised aerodynamic design: Application of parallel computing to car design

The HIPEROAD project has developed a software system capable of performing a semi-automatic optimisation of the shape of sport cars with respect to their aerodynamical properties. The system utilises an aerodynamic solver implemented on parallel MIMD systems, and features advanced tools for the evolution and meshing of car surfaces. The system allows one to include aerodynamic optimisation in the early stages of car design. It has been tested on a Ferrari auto model and full agreement between computed and measured aerodynamical properties was found. The code has been used for designing an optimised model with improved car safety.

A224 地面効果を受ける翼まわりの流れ

This paper describes both the flow field around an airfoil and the aerodynamical properties of the airfoil subjected to the ground effect. The Reynolds number was 1.2×104. Our attention was primarily focussed on pressure measurement on a ground plate. Some specific features of the pressure distribution were clarified. We attempted to evaluate lift acting on the airfoil by performing surface integral of the pressure on the ground. Two types of end plates were tested as a preliminary experiment. The results obtained were anticipated: the pressure tends to become higher as an end plate has such shape as to decrease the spanwise velocity component over the airfoil. The results of the measured pressure distribution were found, in general, to reflect strongly enough the features of the flow field visualized by the smoke wire method.

大麦群落の穂の揺れの風速依存性

To investigate dependencies in the magnitudes of a waving ear on mean wind speed, field observations were carried out over a barley filed in the ripe stage. Fluctuating displacements derived from HONAMI were measured using a newly designed 2-dimension strain sensor. The velocity fields were measured by a sonic anemometer-thermometer.A coherently waving phenomena of HONAMI appeared and was evaluated by the fluctuating displacements of a single ear of the stand. Dividing a time series of the fluctuating displacement into five typical bands of frequency by use of an analog filter, it was shown that there are two dominants of 0.5-Hz and below 0.1-Hz in the original. The bands were from a natural frequency and a gustness of wind respectively. Comparing the amplitudes, the natural frequency contributed remakably to the original fluctuation of HONAMI.Magnitudes of an instantaneous ear-displacement, which represents 0.5-0.6-Hz of frequency, varied with increments of the mean wind speed within a range of 2.6-4.4-m/s. Except for this range, the dependency between the amplitude and the wind speed was not clear.Instantaneous changes in lateral displacements and velocity fluctuations were quite similar except for the component of higher frequencies. Under such circumstances, an ear-displacement will appear to infulence strongly the aero-dynamical properties of the canopy boundary layer.The force per unit length acts on a waving ear generates by a relative velocity of u-dx/dt. Here, u is the mean wind speed, and dx is the displacement of an ear from its mean position during dt. Using this concept, drug force was evaluated under two criteria for leeward ear-moving and ear-standing. Under the windy conditions, the force loaded on an waving ear reduced by 10% against the standing criterion with dx=0. On the other hand, the reduction rate became small down to 4% of the standing criterion under the condition of weak wind.

Circular pipe-connections

Technical designers sometimes need specially formed pipe bends to connect given openings. Choosing a curve of constant curvature for the central curve of such a pipe-connection improves its aerodynamical properties. Further pipe bends with circular central curve are much easier to produce than that based on arbitrary spatial curves. Hence the following geometric problem arises: Let ( A, a), ( B, b) be given line elements with skew oriented tangent lines a, b. How to connect these two elements by a smooth curve? How to fulfill additional requirements? Within the continuum of possible connections we pay attention only to the following four cases: The connecting curve is a helix or it consists of two circles, of n ≧ 2 congruent circular arcs with congruent twist angles or of n ≧ 3 congruent circular arcs with almost congruent twist angles. Solutions of the first and third kind turn out to exist only if the given line elements are symmetric in a certain sense. We present an algorithm for generating curves of the fourth type with the aid of computers.