1,814 research outputs found
Kinematic assessment of subject personification of human body models (THUMS)
The goal of this study was to quantify the effect of improving the geometry of a human body model on the accuracy of the predicted kinematics for 4 post-mortem human subject sled tests. Three modifications to the computational human body model THUMS were carried out to evaluate if subject personification can increase the agreement between predicted and measured kinematics of post-mortem human subjects in full frontal and nearside oblique impacts. The modifications consisted of: adjusting the human body model mass to the actual subject mass, morphing it to the actual anthropometry of each subject and finally adjustment of the model initial position to the measured position in selected post-mortem human subject tests. A quantitative assessment of the agreement between predicted and measured response was carried out by means of CORA analysis by comparing the displacement of selected anatomical landmarks (head CoG, T1 and T8 vertebre and H-Point). For all three scenarios, the more similar the human body model was to the anthropometry and posture of the sled tested post-mortem human subject, the more similar the predictions were to the measured responses of the post-mortem human subject, resulting in higher CORA score
Surface embedding, topology and dualization for spin networks
Spin networks are graphs derived from 3nj symbols of angular momentum. The
surface embedding, the topology and dualization of these networks are
considered. Embeddings into compact surfaces include the orientable sphere S^2
and the torus T, and the not orientable projective space P^2 and Klein's bottle
K. Two families of 3nj graphs admit embeddings of minimal genus into S^2 and
P^2. Their dual 2-skeletons are shown to be triangulations of these surfaces.Comment: LaTeX 17 pages, 6 eps figures (late submission to arxiv.org
PEER TUTORING: EXPLORING THE EFFECTS ON LEARNING GRADE 9 MATHEMATICS
This descriptive-comparative study aimed to develop session plans with learning activities for peer tutoring on quadratic equations. It involved five classes of Grade 9 students of Bantayan National High School, Tabaco City, Albay, Philippines wherein one class was randomly selected as the peer tutored group while the remaining four classes were considered the non-peer tutored groups. The peer tutoring sessions were conducted during the Independent/Cooperative Learning (ICL) period. The sources of data included the students’ reflection entries, observation notes, responses from focus group discussions, and periodic examination results. Findings showed that there were nine session plans with learning activities developed with the integration of cooperative and contextualized learning approaches. The peer tutors were able to master the lessons since they have the opportunity to study it again and revise what they have learned. They also gained more friends, boosted their confidence, and became more interested and enthusiastic in learning and teaching Mathematics together with their peer tutees. On the other hand, the peer tutees grasped the lessons because their tutor gave immediate feedback to them. They also learned how to cooperate and participate with their group to achieve their goal. It was also showed that the peer tutees were very much engaged and eager to learn during the peer tutoring. These were some of the significant learning experiences of the peer tutors and peer tutees during the conduct of peer tutoring. In terms of performance, based on the results of their periodic examination, the peer tutored group had a better performance than those non-peer tutored groups. The session plans with learning activities for peer tutoring were then concluded to give benefits in the learning experiences and enhanced the Mathematics performance of the learners
Long-range repulsive interaction between TTF molecules on a metal surface induced by charge transfer
The low-coverage adsorption of a molecular electron donor,
tetrathiafulvalene, on Au(111) is characterized by the spontaneous formation of
superlattice of monomers, whose spacing exceeds the equilibrium distance of
non-covalent interactions and depends on coverage. The origin of this peculiar
growth mode is due to a long-range repulsive interaction between molecules. The
analysis of molecular-pair distributions obtained by scanning tunneling
microscopy measurements permits us to determine that the nature of TTF
intermolecular interactions on Au (111) is electrostatic. A repulsion between
molecules is caused by the accumulation of charge due to electron donation into
the metal surface, as pictured through density functional theory calculations
Monolithic Solid Based on Single-Walled Carbon Nanohorns: Preparation, Characterization, and Practical Evaluation as a Sorbent
A monolithic solid based solely on single walled carbon nanohorns (SWNHs) was prepared
without the need of radical initiators or gelators. The procedure involves the preparation of a wet
jelly-like system of pristine SWNHs followed by slow drying (48 h) at 25 C. As a result, a robust
and stable porous network was formed due to the interaction between SWNHs not only via - and
van der Waals interactions, but also via the formation of carbon bonds similar to those observed
within dahlia aggregates. Pristine SWNHs and the SWNH monolith were characterized by several
techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM),
confocal laser scanning microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS),
and nitrogen intrusion porosimetry. Taking into account the efficiency of carbon nanoparticles in
sorption processes, the potential applicability of the SWNH-monolith in this research field was
explored using toluene; m-, p-, and o-xylene; ethylbenzene; and styrene, as target analytes. Detection
limits were 0.01 g L�����1 in all cases and the inter-day precision was in the interval 7.4–15.7%.
The sorbent performance of the nanostructured monolithic solid was evaluated by extracting the
selected compounds from different water samples with recovery values between 81.5% and 116.4%
Finite-Dimensional Calculus
We discuss topics related to finite-dimensional calculus in the context of
finite-dimensional quantum mechanics. The truncated Heisenberg-Weyl algebra is
called a TAA algebra after Tekin, Aydin, and Arik who formulated it in terms of
orthofermions. It is shown how to use a matrix approach to implement analytic
representations of the Heisenberg-Weyl algebra in univariate and multivariate
settings. We provide examples for the univariate case. Krawtchouk polynomials
are presented in detail, including a review of Krawtchouk polynomials that
illustrates some curious properties of the Heisenberg-Weyl algebra, as well as
presenting an approach to computing Krawtchouk expansions. From a mathematical
perspective, we are providing indications as to how to implement in finite
terms Rota's "finite operator calculus".Comment: 26 pages. Added material on Krawtchouk polynomials. Additional
references include
The discretised harmonic oscillator: Mathieu functions and a new class of generalised Hermite polynomials
We present a general, asymptotical solution for the discretised harmonic
oscillator. The corresponding Schr\"odinger equation is canonically conjugate
to the Mathieu differential equation, the Schr\"odinger equation of the quantum
pendulum. Thus, in addition to giving an explicit solution for the Hamiltonian
of an isolated Josephon junction or a superconducting single-electron
transistor (SSET), we obtain an asymptotical representation of Mathieu
functions. We solve the discretised harmonic oscillator by transforming the
infinite-dimensional matrix-eigenvalue problem into an infinite set of
algebraic equations which are later shown to be satisfied by the obtained
solution. The proposed ansatz defines a new class of generalised Hermite
polynomials which are explicit functions of the coupling parameter and tend to
ordinary Hermite polynomials in the limit of vanishing coupling constant. The
polynomials become orthogonal as parts of the eigenvectors of a Hermitian
matrix and, consequently, the exponential part of the solution can not be
excluded. We have conjectured the general structure of the solution, both with
respect to the quantum number and the order of the expansion. An explicit proof
is given for the three leading orders of the asymptotical solution and we
sketch a proof for the asymptotical convergence of eigenvectors with respect to
norm. From a more practical point of view, we can estimate the required effort
for improving the known solution and the accuracy of the eigenvectors. The
applied method can be generalised in order to accommodate several variables.Comment: 18 pages, ReVTeX, the final version with rather general expression
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