10,677 research outputs found
Indium adhesion provides quantitative measure of surface cleanliness
Indium tipped probe measures hydrophobic and hydrophilic contaminants on rough and smooth surfaces. The force needed to pull the indium tip, which adheres to a clean surface, away from the surface provides a quantitative measure of cleanliness
Final data reduction and analysis of the AS and E OSO-4 grazing incidence X-ray telescope experiment
Final data analysis of grazing incidence of solar X ray telescope experiment of OSO- 4 satellit
The Critical Exponent is Computable for Automatic Sequences
The critical exponent of an infinite word is defined to be the supremum of
the exponent of each of its factors. For k-automatic sequences, we show that
this critical exponent is always either a rational number or infinite, and its
value is computable. Our results also apply to variants of the critical
exponent, such as the initial critical exponent of Berthe, Holton, and Zamboni
and the Diophantine exponent of Adamczewski and Bugeaud. Our work generalizes
or recovers previous results of Krieger and others, and is applicable to other
situations; e.g., the computation of the optimal recurrence constant for a
linearly recurrent k-automatic sequence.Comment: In Proceedings WORDS 2011, arXiv:1108.341
Renormalization and blow up for charge one equivariant critical wave maps
We prove the existence of equivariant finite time blow up solutions for the
wave map problem from 2+1 dimensions into the 2-sphere. These solutions are the
sum of a dynamically rescaled ground-state harmonic map plus a radiation term.
The local energy of the latter tends to zero as time approaches blow up time.
This is accomplished by first "renormalizing" the rescaled ground state
harmonic map profile by solving an elliptic equation, followed by a
perturbative analysis
Influence of the pH of Chardonnay must on malolactic fermentation induced by bacteria co-inoculated with yeasts
Research Note
1,8‐Bis(diphenylamino)‐ and 1,8‐Bis(methylphenylamino)naphthalene: Molecular Structure and Dynamic Behavior
The title compounds 2 and 3 have been synthesized from 1,8‐diaminonaphthalene. The molecular structure of 2 has been determined by X‐ray structure analysis and is discussed with regard to the arrangement of the peri‐diphenylamino substituents in the crystalline state and the steric strain in the molecule. NMR studies of 3 reveal two conformational processes. Their nature is discussed and barriers are reported
Continuing data analysis of the AS/E grazing incidence X-ray telescope experiment on the OSO-4 satellite
The work to correct and extend the calculation of the theoretical solar X-ray spectrum produced during earlier OSO-4 data analysis is reported along with the work to formulate models of active regions, and compare these models with the experimental values. An atlas of solar X-ray photographs is included, and solar X-ray observations are correlated with the solar wind
Sofic-Dyck shifts
We define the class of sofic-Dyck shifts which extends the class of
Markov-Dyck shifts introduced by Inoue, Krieger and Matsumoto. Sofic-Dyck
shifts are shifts of sequences whose finite factors form unambiguous
context-free languages. We show that they correspond exactly to the class of
shifts of sequences whose sets of factors are visibly pushdown languages. We
give an expression of the zeta function of a sofic-Dyck shift
Dynamics of digging in wet soil
Numerous animals live in, and locomote through, subsea soils. To move in a
medium dominated by frictional interactions, many of these animals have adopted
unique burrowing strategies. This paper presents a burrowing model inspired by
the Atlantic razor clam ({\it Ensis directus}), which uses deformations of its
body to cyclically loosen and re-pack the surrounding soil in order to locally
manipulate burrowing drag. The model reveals how an anisotropic body --
composed of a cylinder and sphere varying sinusoidally in size and relative
displacement -- achieves unidirectional motion through a medium with variable
frictional properties. This net displacement is attained even though the body
kinematics are reciprocal and inertia of both the model organism and the
surrounding medium are negligible. Our results indicate that body aspect ratio
has a strong effect on burrowing velocity and efficiency, with a well-defined
maximum for given kinematics and soil material properties
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