bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancing the Predictive Capabilities of Microstructure Simulations of PBF-LB/M by an Evaluation of Nucleation Theories
Authors: Panzer Hannes , Buss Lorenz , Zaeh Michael F. 
Published: February 2023

AbstractPowder Bed Fusion of Metals using a Laser Beam (PBF-LB/M) has proven to be a competitive manufacturing technology to produce customized parts with a high geometric complexity. Due to process-specific characteristics, such as high cooling rates, the microstructural features can be tailored. This offers the possibility to locally control the mechanical properties. Therefore, the grain structure has to be reliably predicted at first. The starting point of the grain formation and the growth process is characterized by the nucleation. Over the course of this study, various nucleation theories were applied to the PBF-LB/M process and their suitability was evaluated. The two Sc-modified aluminum alloys Scalmalloy® and Scancromal® were processed with a novel experimental PBF-LB/M setup. By performing melt pool simulations based on the Finite Element Method (FEM), the input data for the nucleation models were obtained. The simulatively predicted nucleation zones based on the different theories were compared to real metallographic images and to literature results. It was found that the phenomenological approach should be used whenever no first-time-right prediction of the simulation is necessary. The physically based models with the heterogeneous nucleation should be applied if a first-time-right prediction is striven for. For applications in PBF-LB/M, the nucleation models should be extended in terms of the influence of precipitates and the high cooling rates during the manufacturing process. The presented approach may be used to further assess grain nucleation models for various additive manufacturing processes.
The influence of energy management systems on the progress of efficient energy use in cross-cutting technologies in companies
Authors: Knayer Tobias , Kryvinska Natalia 
Published: February 2023

AbstractThe implementation of energy efficiency measures in companies is the key to a successful energy transition. To that end, companies should improve their energy efficiency and achieve energy savings. The aim of this paper is to present the current status of energy efficiency in companies based on selected cross-cutting technologies and to empirically investigate the implementation status of these measures. For this purpose, a multiple case study was conducted with 386 companies from different industries. The data basis of the case study was generated by means of questionnaires, interviews, and expert visits, and the data were collected within the framework of the Network of Regional Competence Centers for Energy Efficiency, an EU-funded project. A comparison of the potentials of companies with an energy management system in accordance with ISO 50001 and companies without such a system was carried out on the basis of 12 cross-cutting technologies. Statistical evaluation methods and hypothesis testing of eleven hypotheses and nine expressions were used. Our case study showed that (1) the level of energy efficiency in companies is highly dependent on the measure considered. (2) Simple measures have lower potentials than more complex, cost-intensive measures. (3) A positive effect of energy management on energy efficiency in general and on individual measures such as lighting technology, energy monitoring, peak load management, and energy purchasing is empirically confirmed. Further studies should investigate the interaction and correlation of individual efficiency measures (e.g., investments and organizational measures in cross-cutting technologies) in companies to make more targeted statements about the companies' needs and to create efficient support programs.
Evolution of sex determination in crustaceans
Authors: Ye Zhiqiang , Bishop Trent , Wang Yaohai , Shahriari Ryan , Lynch Michael 
Published: February 2023

AbstractSex determination (SD) involves mechanisms that determine whether an individual will develop into a male, female, or in rare cases, hermaphrodite. Crustaceans harbor extremely diverse SD systems, including hermaphroditism, environmental sex determination (ESD), genetic sex determination (GSD), and cytoplasmic sex determination (e.g., Wolbachia controlled SD systems). Such diversity lays the groundwork for researching the evolution of SD in crustaceans, i.e., transitions among different SD systems. However, most previous research has focused on understanding the mechanism of SD within a single lineage or species, overlooking the transition across different SD systems. To help bridge this gap, we summarize the understanding of SD in various clades of crustaceans, and discuss how different SD systems might evolve from one another. Furthermore, we review the genetic basis for transitions between different SD systems (i.e., Dmrt genes) and propose the microcrustacean Daphnia (clade Branchiopoda) as a model to study the transition from ESD to GSD.
Tail index partition-based rules extraction with application to tornado damage insurance
Authors: Maillart Arthur , Robert Christian Y. 
Published: February 2023

AbstractThe tail index is an important parameter that measures how extreme events occur. In many practical cases, this tail index depends on covariates. In this paper,we assume that it takes a finite number of values over a partition of the covariate space. This article proposes a tail index partition-based rules extraction method that is able to construct estimates of the partition subsets and estimates of the tail index values. The method combines two steps: first an additive tree ensemble based on the Gamma deviance is fitted, and second a hierarchical clustering with spatial constraints is used to estimate the subsets of the partition. We also propose a global tree surrogate model to approximate the partition-based rules while providing an explainable model from the initial covariates. Our procedure is illustrated on simulated data. A real case study on wind property damages caused by tornadoes is finally presented.
The influence of unsteady aerodynamics and
inter-blade aerodynamic coupling on the blades
responses to harmonic variations of their pitch
angles
Authors: Rosen A. , Isser A. , Yoshpe M. 
Published: February 2023

AbstractDuring recent years a new vortex model of the unsteady
aerodynamics of a hovering rotor or a rotor in axial
flight, named Temura, has been
developed in the Technion. This model has succeeded
in describing various phenomena of rotor dynamics.
In the present paper Temura is used
in order to develop a model which describes the
blades’ responses to harmonic variations of their
pitch angles. This model includes unsteady
influences of trailing and shed vortices, together
with unsteady geometric effects which represent a
special capability of Temura. The
model is general and can be applied to any number of
blades and arbitrary differences between the pitch
angle variations of different blades. The
application of the model to analyse cases of
collective harmonic pitch variations and
differential harmonic pitch variations is presented.
Numerical results of the new model are compared with
experimental results from the literature and good
agreement is shown.
Rapid determination of aerodynamic
sensitivity derivatives for subsonic
wings
Authors: Mingchu X. , Wenying G. 
Published: February 2023

SummaryA rapid quasi-analytical method — low order
perturbation panel method — is presented for
calculating aerodynamic sensitivity derivatives for
subsonic wings. The method is based on the low order
panel method with the internal Dirichlet problem
formulation and analytical differentiations cascaded
and inverted. In terms of doublet strength
sensitivity to configuration geometry, the computing
cost of the present method for the partial
derivative matrix calculation is less than one order
of magnitude than the existing high order
perturbation panel method, but the accuracy is
comparable. Furthermore, by applying a physical
interpolation instead of a weighted geometrical
interpolation, the sensitivity derivatives of
pressure, lift and pitching moment coefficient with
respect to configuration geometry are derived and
calculated in the present paper. Such sensitivity
derivatives are lacking in high order perturbation
panel method. A few calculative examples are
given.
On the effect of uniform suction on
stability and transition in zero pressure gradient
viscous incompressible flow
Authors: Poll D. I. A. , Walsh S. A. , Gallagher M. C. 
Published: February 2023

AbstractThe classic problem of stability and transition to
turbulence of an incompressible flow over a flat
plate subjected to uniform suction through the
surface is considered. This is an important “model”
problem for laminar flow control and the results
have direct application to the design of low drag
aerofoils. Detailed mean boundary layer calculations
are presented and the flow stability is determined
by obtaining numerical solutions of the
Orr-Somerfield equation. Transition conditions are
estimated by using the semi-empirical en method.
Accurate values have been obtained for the levels of
suction necessary to delay instability and
transition indefinitely. Consideration has also been
given to the effect of surface suction upon the
plate drag.
Measurement of drag using a momentum
balance
Authors: Squire L. C. 
Published: February 2023

SummaryThis note presents the results of the application of a
momentum control surface analysis to the estimation
of the drag of bodies and surfaces placed in the
test section of a windtunnel. The assumptions of the
method are stated and accuracy of the method
considered with particular reference to the drag of
riblet surfaces at high subsonic speeds, the drag of
two-dimensional cavities at both high subsonic and
low supersonic speeds, and the drag of manipulators
at high subsonic speeds.
Optimal load limiting parachute inflation
control
Authors: Redmond J. , Parker G. G. , Hinnerichs T. D. 
Published: February 2023

AbstractExcessive deceleration forces experienced during high
speed deployment of parachute systems can cause
damage to the payload and the canopy fabric.
Conventional reefing lines offer limited relief by
temporarily restricting canopy inflation and
limiting the peak deceleration load. However, the
open-loop control provided by existing reefing
devices restricts their use to a specific set of
deployment conditions. The sensing, processing, and
actuation which are characteristic of adaptive
structures form the basis of three concepts for
active control of parachute inflation. These active
control concepts are incorporated into a computer
simulation of parachute inflation. Initial
investigations indicate that these concepts promise
enhanced performance as compared to conventional
techniques for a nominal release. Furthermore, the
ability of each controller to adapt to off-nominal
release conditions is examined.
A study of the three-dimensional
interaction of wakes and boundary
layers
Authors: Yeung C. P. , Squire L. C. 
Published: February 2023

SummaryThis paper concerns the study of the three-dimensional
interaction of a slat wake and a wing boundary
layer, as commonly occurs on the suction surface of
a high-lift rnulti-element aerofoil. The
experimental test case has a realistic slat-wing
flow configuration under infinite swept wing
conditions. This enables the effect of the cross
flow induced by the wing sweep on the slat wake and
the wing boundary layer interaction process to be
investigated. A triple hot-wire system has been used
to measure the mean velocity and Reynolds stress
components in the flow field. The measurements are
used to validate a three-dimensional boundary layer
code, which has been modified to calculate this
three-dimensional wake-boundary layer mixing
flow.
Modelling the formation and dispersal of
streamwise vortices in turbulent
flow
Authors: Launder B. E. 
Published: February 2023

Abstract In many practical circumstances in aeronautical
engineering and in related industries, flows arise
where concentrated streamwise vorticity is embedded
within a turbulent shear flow. The juxtaposition of
these features makes such flows particularly
challenging to compute using CFD methods. In
particular, one may be forced to abandon strategies
for modelling the turbulent stresses that prove
adequate in two dimensional shear flows (i.e. in
flows where the vorticity vector is orthogonal to
the mean velocity). The paper reviews developments
in modelling turbulent stresses from their transport
equations (rather than by appeal to an eddy
viscosity hypothesis) and demonstrates, by way of a
range of examples, the capabilities of this approach
for handling flows with concentrated streamwise
vorticity.
Absolute and convective instabilities in
separation bubbles
Authors: Allen T. , Riley N. 
Published: February 2023

Abstract At a sufficiently high Reynolds number small
separation bubbles, as for example at the
leading-edge of an aerofoil, are characterised by
laminar flow separation and turbulent reattachment.
The transition to turbulence in the separated-flow
region through the introduction of a disturbance at
the boundary, localised in time and space, is
examined. It is found that transition to turbulence
is promoted by rapidly growing convective
instabilities, and not an absolute instability at
the point of application of the disturbance.
Aircraft parameter identification using an
estimation-before-modelling
technique
Authors: Hoff J. C. , Cook M. V. 
Published: February 2023

AbstractThis paper describes a comparative evaluation of two
data smoothing algorithms for use in a two step
estimation-beforemodelling procedure for aircraft
parameter identification. A simple fixed lag
smoother is compared with the usual, and more
complex, modified-Bryson-Frazier smoother in the
first, state estimation, step of the aircraft
parameter identification procedure. The comparison
is illustrated by application to the analysis of the
Dutch Roll motion of the Embraer EMB-312 Tucano.
Both algorithms were found to give results of
comparable accuracy although the fixed lag smoother
is computationally more efficient. It was concluded
that the fixed lag smoother algorithm is an
acceptable alternative to the
modified-Bryson-Frazier algorithm in aircraft
parameter identification applications.
Experimental studies on flow transition of
a plane wall jet
Authors: Hsiao F.-B. , Sheu S.-S. 
Published: February 2023

SummaryFlow transition in the developing region of a plane
wall jet is studied experimentally by means of
hot-wire measurements. The Reynolds number, based on
the jet exit velocity and nozzle exit height, varies
from 3 x 102 to 3 x 104 in the
investigations. The results indicate that the most
important factor causing wall jet flow to change
from the initial exit state to the final turbulent
state is the rapid increase of turbulent intensity
from the formation of vortical structures and their
interactions with the wall. Data also shows that the
transition process of the wall jet depends on the
Reynolds number in the operating range. When the
Reynolds number is greater than 2000, the mean
velocity distribution of the wall jet changes
directly from a top-hat profile at the nozzle exit
to a turbulent profile in the turbulent developed
region. When the Reynolds number is smaller than
2000, Glauert's laminar velocity profile is found
between the nozzle exit and the turbulent region. It
is also found that the transition will be delayed
and the transition region prolonged with the
decrease of the Reynolds number.
Aeroelastic design and flight test
evaluation of the Ranger 2000 training
aircraft
Authors: Schweiger J. , Weiss F. , Dobbs S. K. 
Published: February 2023

AbstractThe paper describes the aeroelastic analysis for the
design, the ground verification tests and the flight
test programme, for the Ranger 2000 training
aircraft, developed jointly by Dasa and Rockwell
International between 1991 and 1994, as a competitor
for the next generation US Air Force and Navy Joint
Primary Advanced Training System (JPats). Special
efforts with respect to the aeroelastic stability
were required for the T-tail configuration, for the
design of the manual flight control system, and for
the establishment of sufficient mass balance for the
control surfaces. Several ground vibration tests
were performed for the complete aircraft and for
individual components for all major design
improvements during the flight test evaluation. To
minimise the required time for these tests, highly
modular test equipment was required. For an
efficient flutter flight test programme a reliable
excitation system was chosen. This system consists
of slotted rotating cylinders, mounted on small
vanes, which can be attached to any aerodynamic
surface. This equipment creates defined unsteady
aerodynamic forces to excite the eigenmodes of the
structure.Quasi-on-line frequency and damping data evaluation
between consecutive flight test points was made
possible by installing the required hardware and
software directly at the flight test quick-look
control room, for the direct use of telemetry data.
With this approach only a small number of dedicated
flutter flights was required.
An experimental investigation into yaw
control at high alpha on a chined forebody using
slot blowing
Authors: Williams S. P. , Garry K. P. 
Published: February 2023

AbstractResults are presented from low-speed windtunnel tests
on an isolated generic chined forebody with
pneumatic methods of yaw control at high alpha.
Measurements of forces and moments were made on the
forebody at angles of attack in the range 0° ≤ ɑ ≤
60°. Slot blowing through the chine edge at various
angles and upper surface tangential blowing have
been compared, and optimum configurations have been
identified. The effects of forebody cross-sectional
shape have also been investigated and have been
found to be highly critical in determining blowing
effectiveness. Limited flowfield visualisation is
also presented in order to gain some understanding
of the flow field characteristics.
Transient finite element dynamic response
of laminated composite stiffened
shell
Authors: Mukhopadhyay M. , Goswami S. 
Published: February 2023

AbstractThe paper uses the conventional nine-noded Lagrangian
element for studying transient linear response
analysis of composite stiffened shells. An improved
version of the stiffener modelling has been used in
which the stiffener can be placed anywhere inside
the element. For the first time, concentric or
eccentric stiffeners have been used for composite
stiffened shells for solving the transient dynamic
response of these structures. These are not
available in existing commercial packages. Different
types of time dependent loading such as short
duration air-blast loading, suddenly applied
uniformly distributed step loading and sinusoidally
harmonic loading have been considered in this paper.
The results of stiffened composite cylindrical
shells and doubly curved shells with different
boundary conditions and various laminate
orientations have been presented for eccentric
stiffeners. Parametric studies considering different
variables have also been carried out.
Technical Note
Authors: Traub L. W. 
Published: February 2023

AbstractA theoretical study was undertaken to determine the
effect of taper ratio on the trailing vortex
structure of a high aspect ratio unswept wing. The
wing was modelled using lifting line theory, and the
vortex was assumed to have a Rankine distribution of
circulation. The results show that reducing the
taper ratio of the wing, decreases the maximum
tangential velocity of the vortex as well as the
vortex span while the core's diameter increases.
Data is also presented showing the sensitivity of
induced drag to wake vortex parameters.
Improved methodology for inverse
simulation
Authors: Rutherford S. , Thomson D.G. 
Published: February 2023

SummaryInverse simulation is becoming a more widely used
technique in flight mechanics studies. The ability
to predict control and response time histories for a
predefined manoeuvre or task has obvious benefits in
certain applications (handling qualities studies
related to the ADS-33 requirements for helicopters,
for example). The main criticisms of the technique
have always been concerned with the numerical
problems usually encountered when solving the
equations of motion in the inverse manner. In this
paper these problems are highlighted and a simple
technique which overcomes them is presented. This
technique provides a robust mechanism whereby
reliable and consistent inverse simulations are
possible.
Collectively variable incidence wingtips
for lift control and reduced gust
sensitivity
Authors: Barnard R.H. 
Published: February 2023

AbstractThis paper describes an investigation of the
aerodynamic characteristics of collectively variable
incidence wing tips at low speeds. Theoretical
considerations supported by experimental
measurements suggest that the use of articulated
tips which can be rotated to a high incidence for
low speed flight will decrease sensitivity to gusts.
Furthermore, windtunnel measurements demonstrate
that the use of very high tip incidences can produce
an increment in maximum overall lift coefficient for
some wing configurations. Another feature
investigated is the possibility of utilising the
lift increment for the purposes of direct lift
control. The use of a radio controlled model to test
the practical viability of the concept is
described.
Volcanic Emissions, Plume Dispersion, and Downwind Radiative Impacts Following Mount Etna Series of Eruptions of February 21–26, 2021
Authors: Sellitto P. , Salerno G. , Corradini S. , Xueref‐Remy I. , Riandet A. , Bellon C. , Khaykin S. , Ancellet G. , Lolli S. , Welton E. J. , Boselli A. , Sannino A. , Cuesta J. , Guermazi H. , Eremenko M. , Merucci L. , Stelitano D. , Guerrieri L. , Legras B. 
Published: February 2023

AbstractDuring the extended activity of Mount Etna volcano in February–April 2021, three distinct paroxysmal events took place from February 21 to 26, which were associated with a very uncommon transport of the injected upper‐tropospheric plumes toward the north. Using a synergy of observations and modeling, we characterized the emissions and three‐dimensional dispersion for these three plumes, monitored their downwind distribution and optical properties, and estimated their radiative impacts at selected locations. With a satellite‐based source inversion, we estimate the emitted sulfur dioxide (SO2) mass at an integrated value of 55 kt and plumes injections at up to 12 km altitudes, which qualifies this series as an extreme event for Mount Etna. Then, we combine Lagrangian dispersion modeling, initialized with measured temporally resolved SO2 emission fluxes and altitudes, with satellite observations to track the dispersion of the three individual plumes. The transport toward the north allowed the height‐resolved downwind monitoring of the plumes at selected observatories in France, Italy, and Israel, using LiDARs and photometric aerosol observations. Volcanic‐specific aerosol optical depths (AODs) in the visible spectral range ranging from about 0.004 to 0.03 and local daily average shortwave radiative forcing (RF) ranging from about −0.2 to −1.2 W m−2 (at the top of atmosphere) and from about −0.2 to −3.0 W m−2 (at the surface) are found. The composition (possible presence of ash), AOD, and RF of the plume have a large inter‐plume and intra‐plume variability and thus depend strongly on the position of the sampled section of the plumes.