19,141 research outputs found
Effect of debonding on natural frequencies and frequency response functions of honeycomb sandwich beams
No full textThe natural frequencies of honeycomb sandwich beams having debonding or delamination embedded between the face-layer laminates and the honeycomb core are studied herein. A theoretical analysis of the effect of the extent of debonding on the flexural stiffness and on the natural frequency is compared with experimental observations. In this analysis the free vibration of the delaminated sandwich beams is studied using the split sandwich beam model, and the equations of motion are set up for the undelaminated region of the sandwich beam and the delaminated region of the laminated beams. Finally, changes in the peaks and valleys of the frequency response functions (FRFs) due to delamination are examined. By using the modal parameter identification method [H.Y. Kim, W. Hwang, Compos. Struct., 2001 (in press)], the extent of delamination of the sandwich beams can be identified in terms of the natural frequencies and damping ratios of the debonded beams. Vibration testing was conducted on honeycomb sandwich beams with carbon/epoxy laminated composite faces and Nomex-aramid honeycomb core. Agreement between the predictions of the model and experimental results is good. (C) 2001 Elsevier Science Ltd. All rights reserved.X1155sciescopu
Fatigue life prediction of circular notched CFRP laminates
No full textFatigue life prediction and fatigue behavior of circular notched carbon fiber reinforced plastic laminates are presented. Point and average stress criteria proposed by Whitney and Nuismer are generalized to fatigue fracture criteria for notched laminates. Residual strength degradation model and the assumptions on the stress redistribution are introduced during the derivation of prediction equations. S-N curve, Basquin's relation, and Hwang and Han's fatigue life prediction equation (FLPE) 1 are chosen for evaluation of residual strength of unnotched laminates and six prediction equations are derived. Experiments are performed using carbon fiber reinforced plastic laminates. Presented prediction equations are reasonably close to experimental data and proposed approach is found to be suitable to predict fatigue life of notched composite laminates. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.X1111sciescopu
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Retraction: Site‐specific recombination of nitrogen‐fixation genes in cyanobacteria by XisF–XisH–XisI complex: Structures and models, William C. Hwang, James W. Golden, Jaime Pascual, Dong Xu, Anton Cheltsov, Adam Godzik
No full textThe above article from the Proteins: Structure, Function, and Bioinformatics, published online on 1 September 2014 in Wiley Online Library as Accepted Article (http://onlinelibrary.wiley.com/doi/10.1002/prot.24679/full), has been retracted by agreement between William C. Hwang, James W. Golden, Jaime Pascual, Dong Xu, Anton Cheltsov, Adam Godzik, the Editor‐in‐Chief, Bertrand E. Garcia‐Moreno, and Wiley Periodicals, Inc. The retraction has been agreed because submission was made without agreement from co‐author Adam Godzik
Nanophysoderes dentiscutum Hwang & Weirauch 2017, comb. nov.
No full textNanophysoderes dentiscutum (Bergroth, 1906) comb. nov. Figs 10–11, 13; Appendix Physoderes dentiscutum Bergroth, 1906: 16. Diagnosis As in generic description. Material examined Holotype INDONESIA: ♀, Irian Jaya, W New Guinea, 4.24891° S, 135.79065° E, 285 m, 1869, Higgins leg. (UCR_ENT 00037370) (ISNB). Redescription As in generic description.Published as part of Hwang, Wei Song & Weirauch, Christiane, 2017, Uncovering hidden diversity: phylogeny and taxonomy of Physoderinae (Reduviidae, Heteroptera), with emphasis on Physoderes Westwood in the Oriental and Australasian regions, pp. 1-118 in European Journal of Taxonomy 341 on page 61, DOI: 10.5852/ejt.2017.341, http://zenodo.org/record/383279
Toward Understanding the Quark Parton Model of Feynmant
No full textThe quark parton model of Feynman, which has been used for analyses of high energy
physics experiments, invokes a set of parton distributions in the description of the nucleon
structure (the probability concept), contrary to the traditional use of wave functions in nuclear
and medium ener,7 physics for structural studies (the amplitude concept). In this paper, I first
review briefly how the various parton distributions of a nucleon may be extracted from high energy
physics experiments. I then proceed to consider how the sea distributions of a free nucleon at low
and moderate Q2 (e.g., up to 20 Ge?) may be obtained in the meson-baryon picture, a proposal
made by Hwang, Speth, and Brown. Using the form factors associated with the couplings of
mesons to baryons such as nNN, xNA, and KNA couplings which are constrained by the CCFR
neutrino data, we find that the model yields predictions consistent with the CDHS and Fermilab
E61S data on the sea-to-valence ratio. We also find that the recent finding by the New Muon
Collaboration (NMC) on the violation of the Gottfried sum rule can be understood quantitatively.
Finally, we consider, using the pion as the example, how valence quark distributions of a hadron
may be linked to the hadron wave function written in the light-cone language. Specifically, we
use the leading pion wave function that is constrained by the QCD sum rules, and find that, at Q*
= (0.5 Gev2, the leading Fock component accounts for about 40 % of the observed valence quark
distributions in the pion. The question of how to generate the entire valence quark distributions
from the valence quark distribution calculated from the leading Fock component is briefly
considered again using the specific proposal of Hwang, Speth, and Brown
The Western New York Entrepreneurship Ecosystem: Rapid Discovery Assessment and Recommendations for the Future
No full textIn an effort to learn more about the current state of Western New York's entrepreneurial ecosystem and to inform future strategy, the Ralph C. Wilson, Jr. Foundation engaged Victor & Company, led by Victor W. Hwang, to conduct a three-month rapid discovery process.This report was written and published by Victor & Company, led by Victor W. Hwang, with support from the Ralph C. Wilson, Jr. Foundation
Observation of static strength and fatigue life of repaired graphite/epoxy using a tensile coupon
No full textThe static strength and fatigue life of repaired graphite/epoxy laminates was observed using a tensile coupon. The lay-up of investigated laminates was [0 degrees/+/-45 degrees/90 degrees]s. Static strength was measured from the specimens prepared by various repair techniques such as cosmetic treatment, precured-single patch, precured-double patch and cure-in-place patch methods. The strength was recovered to the extent of 60-70% of unnotched case. Fatigue life was also measured from the laminates repaired with cure-in-place patch method. Hwang and Han's MFLPE I (modified fatigue life prediction equation (1)), which is based on the fatigue modulus degradation model and reference modulus, was chosen for fatigue life prediction of the repaired specimen and compared with the conventional fatigue life equations such as the S-N curve and Basquin's relation. The MFLPE 1 agrees more closely with experimental data than the S-N curve or Basquin's relation.X11sciescopu
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