Articles
![]() |
12/06/2021--
12/06/2021
The InSight HP$^3$ mole on Mars: Lessons learned from attempts to penetrate to depth in the Martian soil
The NASA InSight mission payload includes the Heat Flow and Physical
Properties Package HP$^3$ to measure the surface heat flow. The package was
designed to use a small penetrator -- nicknamed the mole -- to implement a
string of temperature sensors in the soil to a depth of 5m. The mole itself is
equipped with sensors to measure a thermal conductivity as it proceeds to
depth. The heat flow would be calculated from the product of the temperature
gradient and the thermal conductivity. To avoid the perturbation caused by
annual surface temperature variations, the measurements would be taken at a
depth between 3 m and 5 m. The mole was designed to penetrate cohesionless soil
similar to Quartz sand which was expected to provide a good analogue material
for Martian sand. The sand would provide friction to the buried mole hull to
balance the remaining recoil of the mole hammer mechanism that drives the mole
forward. Unfortunately, the mole did not penetrate more than a mole length of
40 cm. The failure to penetrate deeper was largely due to a few tens of
centimeter thick cohesive duricrust that failed to provide the required
friction. Although a suppressor mass and spring in the hammer mechanism
absorbed much of the recoil, the available mass did not allow a system that
would have eliminated the recoil. The mole penetrated to 40 cm depth benefiting
from friction provided by springs in the support structure from which it was
deployed. It was found in addition that the Martian soil provided unexpected
levels of penetration resistance that would have motivated to designing a more
powerful mole. It is concluded that more mass would have allowed to design a
more robust system with little or no recoil, more energy of the mole hammer
mechanism and a more massive support structure.
T. Spohn
T. L. Hudson
L. Witte
T. Wippermann
L. Wisniewski
B. Kediziora
C. Vrettos
R. D. Lorenz
M. Golombek
R. Lichtenfeld
M. Grott
J. Knollenberg
C. Krause
C. Fantinati
S. Nagihara
J. Grygorczuk
06/09/2017--
06/09/2017
Autoigniton of n-Butanol at Low to Intermediate Temperature and Elevated Pressure
Autoignition delay experiments were performed for n-butanol in a heated rapid
compression machine. Experiments were performed at pressures of 15 and 30 bar,
in the temperature range 650-900 K, and for equivalence ratios of 0.5, 1.0, and
2.0. Additionally, the initial fuel mole fraction and initial oxygen mole
fraction were varied independently to determine the influence of each on
ignition delay. Over the conditions studied, it was found that the reactivity
of the mixture increased as equivalence ratio, initial fuel mole fraction or
initial oxygen mole fraction increased. A non-linear correlation to the
experimental data was performed and showed nearly second order dependence on
the initial oxygen mole fraction and nearly first order dependence on initial
fuel mole fraction and compressed pressure. This was the first study of the
ignition of n-butanol in this temperature and pressure range, and contributes
to a better understanding of the chemistry of this fuel under the conditions
relevant to practical devices. Experimentally measured ignition delays were
compared against the ignition delay computed from several reaction mechanisms
in the literature. The agreement between experiments and simulations was found
to be unsatisfactory. Sensitivity analysis was performed and indicated that the
uncertainties of the rate constants of parent fuel decomposition reactions play
a major role in causing the poor agreement. Further path analysis of the fuel
decomposition reactions supported this conclusion and highlighted the
particular importance of certain pathways. Based on these results, it was
concluded that further investigation of the fuel decomposition, including
speciation measurements, will be required.
Bryan W. Weber
12/23/2020--
12/23/2020
Effect of Oxygen Mole Fraction on Static Properties of Pressure-Sensitive Paint
The effects of oxygen mole fraction on the static properties of
pressure-sensitive paint (PSP) were investigated. Sample coupon tests using a
calibration chamber were conducted for polymer-based PSP (PHFIPM-PSP),
polymer/ceramic PSP (PC-PSP), and anodized-aluminium PSP (AA-PSP). The oxygen
mole fraction was set to be between 0.1-100% and the ambient pressure was set
to be between 0.5-140 kPa. The localized Stern-Volmer coefficient $B_{\rm
local}$ once increases and then decreases as the oxygen mole fraction
increases. The value of $B_{\rm local}$ depends on both ambient pressure and
oxygen mole fraction, but the effect of this parameter can be characterized as
a function of the partial pressure of oxygen. The value of $B_{\rm local}$ of
AA-PSP and PHFIPM-PSP, which are low-pressure type and relatively low-pressure
type PSP, have a peak at the relatively low partial pressure of oxygen, and
$B_{\rm local}$ of PC-PSP, which are atmospheric pressure type PSP, has a peak
at the relatively high partial pressure of oxygen. The peak of the intensity
change with respect to pressure fluctuation proportional to the ambient
pressure $S_{\mathcal{PR}}$ appears at the lower partial pressure of oxygen
than that of $B_{\rm local}$. This is because the intensity of PSP becomes
quite low at the high partial pressure of oxygen even if $B_{\rm local}$ is
higher. Hence, an optimal partial oxygen mole fraction exists depending on the
type of PSP and ambient pressure range of the experiment, and its optimal value
can be found based on the partial pressure of oxygen.
Tomohiro Okudera
Takayuki Nagata
Miku Kasai
Yuji Saito
Taku Nonomura
Keisuke Asai
04/09/1999--
04/09/1999
The Binary Mole
Avogadro's number is a count of a definite number of things and, therefore,
must be an integer and not a floating point number. Arguments are given herein
that this integer should be precisely 2E79 - that is,
N_o = 2E79 = 6.04 462 909 107 318 607 353 088 E23;
hence, the binary mole.
Joel M. Williams
03/04/2024--
03/04/2024
Non-Abelian extensions of degree $p^3$ and $p^4$ in characteristic $p>2$
This paper describes in terms of Artin-Schreier equations field extensions
whose Galois group is isomorphic to any of the four non-cyclic groups of order
$p^3$ or the ten non-Abelian groups of order $p^4$, $p$ an odd prime, over a
field of characteristic $p$.
Grant Moles
05/16/2011--
02/01/2011
Disequilibrium Carbon, Oxygen, and Nitrogen Chemistry in the Atmospheres of HD 189733b and HD 209458b
We have developed 1-D photochemical and thermochemical kinetics and diffusion
models for the transiting exoplanets HD 189733b and HD 209458b to study the
effects of disequilibrium chemistry on the atmospheric composition of "hot
Jupiters." Here we investigate the coupled chemistry of neutral carbon,
hydrogen, oxygen, and nitrogen species, and we compare the model results with
existing transit and eclipse observations. We find that the vertical profiles
of molecular constituents are significantly affected by transport-induced
quenching and photochemistry, particularly on cooler HD 189733b; however, the
warmer stratospheric temperatures on HD 209458b can help maintain
thermochemical equilibrium and reduce the effects of disequilibrium chemistry.
For both planets, the methane and ammonia mole fractions are found to be
enhanced over their equilibrium values at pressures of a few bar to less than a
mbar due to transport-induced quenching, but CH4 and NH3 are photochemically
removed at higher altitudes. Atomic species, unsaturated hydrocarbons
(particularly C2H2), some nitriles (particularly HCN), and radicals like OH,
CH3, and NH2 are enhanced overequilibrium predictions because of quenching and
photochemistry. In contrast, CO, H2O, N2, and CO2 more closely follow their
equilibrium profiles, except at pressures < 1 microbar, where CO, H2O, and N2
are photochemically destroyed and CO2 is produced before its eventual
high-altitude destruction. The enhanced abundances of HCN, CH4, and NH3 in
particular are expected to affect the spectral signatures and thermal profiles
HD 189733b and other, relatively cool, close-in transiting exoplanets. We
examine the sensitivity of our results to the assumed temperature structure and
eddy diffusion coefficientss and discuss further observational consequences of
these models.
Julianne I. Moses
Channon Visscher
Jonathan J. Fortney
Adam P. Showman
Nikole K. Lewis
Caitlin A. Griffith
Stephen J. Klippenstein
Megan Shabram
A. James Friedson
Mark S. Marley
Richard S. Freedman
05/28/2019--
04/04/2017
Approximation results regarding the multiple-output mixture of linear experts model
Mixture of experts (MoE) models are a class of artificial neural networks
that can be used for functional approximation and probabilistic modeling. An
important class of MoE models is the class of mixture of linear experts (MoLE)
models, where the expert functions map to real topological output spaces. There
are a number of powerful approximation results regarding MoLE models, when the
output space is univariate. These results guarantee the ability of MoLE mean
functions to approximate arbitrary continuous functions, and MoLE models
themselves to approximate arbitrary conditional probability density functions.
We utilize and extend upon the univariate approximation results in order to
prove a pair of useful results for situations where the output spaces are
multivariate.
Hien D. Nguyen
Faicel Chamroukhi
Florence Forbes
04/09/2024--
04/09/2024
AI-MOLE: Autonomous Iterative Motion Learning for Unknown Nonlinear Dynamics with Extensive Experimental Validation
This work proposes Autonomous Iterative Motion Learning (AI-MOLE), a method
that enables systems with unknown, nonlinear dynamics to autonomously learn to
solve reference tracking tasks. The method iteratively applies an input
trajectory to the unknown dynamics, trains a Gaussian process model based on
the experimental data, and utilizes the model to update the input trajectory
until desired tracking performance is achieved. Unlike existing approaches, the
proposed method determines necessary parameters automatically, i.e., AI-MOLE
works plug-and-play and without manual parameter tuning. Furthermore, AI-MOLE
only requires input/output information, but can also exploit available state
information to accelerate learning.
While other approaches are typically only validated in simulation or on a
single real-world testbed using manually tuned parameters, we present the
unprecedented result of validating the proposed method on three different
real-world robots and a total of nine different reference tracking tasks
without requiring any a priori model information or manual parameter tuning.
Over all systems and tasks, AI-MOLE rapidly learns to track the references
without requiring any manual parameter tuning at all, even if only input/output
information is available.
Michael Meindl
Simon Bachhuber
Thomas Seel
09/18/2025--
05/26/2025
MOLE: Metadata Extraction and Validation in Scientific Papers Using LLMs
Metadata extraction is essential for cataloging and preserving datasets,
enabling effective research discovery and reproducibility, especially given the
current exponential growth in scientific research. While Masader (Alyafeai et
al.,2021) laid the groundwork for extracting a wide range of metadata
attributes from Arabic NLP datasets' scholarly articles, it relies heavily on
manual annotation. In this paper, we present MOLE, a framework that leverages
Large Language Models (LLMs) to automatically extract metadata attributes from
scientific papers covering datasets of languages other than Arabic. Our
schema-driven methodology processes entire documents across multiple input
formats and incorporates robust validation mechanisms for consistent output.
Additionally, we introduce a new benchmark to evaluate the research progress on
this task. Through systematic analysis of context length, few-shot learning,
and web browsing integration, we demonstrate that modern LLMs show promising
results in automating this task, highlighting the need for further future work
improvements to ensure consistent and reliable performance. We release the
code: https://github.com/IVUL-KAUST/MOLE and dataset:
https://huggingface.co/datasets/IVUL-KAUST/MOLE for the research community.
Zaid Alyafeai
Maged S. Al-Shaibani
Bernard Ghanem
06/18/2025--
06/18/2025
Mix-of-Language-Experts Architecture for Multilingual Programming
Large language models (LLMs) have demonstrated impressive capabilities in
aiding developers with tasks like code comprehension, generation, and
translation. Supporting multilingual programming -- i.e., coding tasks across
multiple programming languages -- typically requires either (1) finetuning a
single LLM across all programming languages, which is cost-efficient but
sacrifices language-specific specialization and performance, or (2) finetuning
separate LLMs for each programming language, which allows for specialization
but is computationally expensive and storage-intensive due to the duplication
of parameters. This paper introduces MoLE (Mix-of-Language-Experts), a novel
architecture that balances efficiency and specialization for multilingual
programming. MoLE is composed of a base model, a shared LoRA (low-rank
adaptation) module, and a collection of language-specific LoRA modules. These
modules are jointly optimized during the finetuning process, enabling effective
knowledge sharing and specialization across programming languages. During
inference, MoLE automatically routes to the language-specific LoRA module
corresponding to the programming language of the code token being generated.
Our experiments demonstrate that MoLE achieves greater parameter efficiency
compared to training separate language-specific LoRAs, while outperforming a
single shared LLM finetuned for all programming languages in terms of accuracy.
Yifan Zong
Yuntian Deng
Pengyu Nie
|
|