• Fibers and Polymers
• /
• v.2 no.1
• /
• pp.144-147
• /
• 2001

The HVI properites and Mantis single fiber tensile properties were analyzed to evaluate the relationship between fiber and bundle tensile properties. For this study, a new method has been developed for estimating the modulus and toughness of cotton fiber bundles directly from the HVI tenacity-elongation curves. The single fiber tensile properties were shown to be translated well into the bundle tensile properties. The single fiber breaking elongation was found to be the most significant contributing factor to bundle tensile properties. The bundle breaking elongation and toughness were shown to increase as the single fiber breaking elongation increased. The bundle modulus increased as the single fiber breaking elongation and/or standard deviation of single fiber breaking elongation decreased.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.5
• /
• pp.517-523
• /
• 2011

Anterior cruciate ligament (ACL) injuries are treatedwith surgical reconstruction. Although ACL consists of two functional bundles, only the anteromedial bundle is surgically reconstructed, and the effect of the reconstruction of the posterolateral bundle is unknown. The purpose of this study is to investigate the role of the posterolateral bundle and the effect of double-bundle reconstruction during single-leg landing. A 3D dynamic knee with various ACL reconstructed models was created using MRI, and single-leg landing motion was simulated using in-vivo human experimental data. The results showed that the lateral shift of the tibial insertion of the anteromedial bundle and the posterolateral bundle of the ACL constrain the tibial internal rotation more efficiently than a single anteromedial bundle can. In addition, double-bundle ACL reconstruction is less sensitive to inaccuracies in the tibial tunnel placement.

• Journal of the Korean Arthroscopy Society
• /
• v.15 no.2
• /
• pp.125-131
• /
• 2011

Optimal treatment of the torn posterior cruciate ligament (PCL) remains controversial. The type of tibial fixation (transtibial vs inlay), the femoral tunnel position within the femoral footprint (central, eccentric or isometric), and the number of bundles in the reconstruction (single-bundle vs double-bundle) are controversial issues. The PCL has a better chance of spontaneously healing than the anterior cruciate ligament (ACL) because of a rich blood supply (near the branch of the middle genicular artery) and coverage with a thicker synovium. In general, for easier passage of the graft and full visualization of the original ligament attachment site during the precise positioning of the tunnel, the remaining PCL fibers are usually debrided during reconstruction. However, the remaining remnant structures would significantly contribute to the posterior stability of the knee joint, the healing of the graft, preserving proprioceptive function of the mechanoreceptors in the PCL. Double bundle PCL reconstruction may result in some surgical complications because of increased complexity of making tunnel. Therefore, single bundle PCL reconstruction with remnant preservation seems to be an effective procedure.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.8
• /
• pp.862-869
• /
• 2007

The compressive and torsional buckling behavior of carbon nanotube bundles at room temperature is examined with classical molecular dynamics simulation. The critical compressive load and stiffness of a single carbon nanotube in the bundle are found to be similar to those of individual carbon nanotubes. However, the critical torsional moment and stiffness of a single carbon nanotube in the bundle are found to be higher than those of individual carbon nanotubes. In addition, this study demonstrates that van der Waals interactions between the nanotubes in the bundle significantly affect the critical compressive load of the nanotube bundle.

• Journal of the Korean Arthroscopy Society
• /
• v.11 no.2
• /
• pp.92-98
• /
• 2007

Purposes: The purpose of this study was to report surgical technique of double bundle anterior cruciate ligament(ACL) reconstruction and to compare the short-term clinical results between arthroscopic single-bundle and double-bundle ACL reconstruction. Materials and Methods: From May 2005 to May 2006, ninety-eight patients were underwent ACL reconstruction. We designed prospective study with sixty-one patients who were revealed isolated ACL injury. We serially checked clinical and radiologic data preoperatively and postoperatively. We compared single-bundle with double-bundle ACL reconstruction patients with preoperative datas and postoperatively 1-year data. There were 30 single bundle reconstruction and 31 double bundle reconstruction. Stability was assessed objectively by anterior stress radiographs with the $Telos^{(R)}$ device and the maximal manual test with the KT-2000 arthrometer. The clinical results were assessed by IKDC(International Knee Documentation Committee) and OAK(Orthopadische Arbeitsgruppe Knie) scores. Also, we evaluated postoperative thigh circumference and range of motion. All of operations were done by only one surgeon. Results: At single-bundle reconstruction group, preoperative AP instability which was checked by $Telos^{(R)}$ device and the maximal manual test with the KT-2000 arthrometer was $7.9{\pm}3.3$ and $7.4{\pm}2.0$, respectively. At double-bundle reconstruction group, it was $8.3{\pm}3.5$ and $7.9{\pm}3.2$, respectively. Residual AP laxity checked at 1 year after operation was $1.9{\pm}1.2$ and $2.2{\pm}1.6$ in single-bundle reconstruction group, and $1.1{\pm}0.9$ and $1.0{\pm}1.0$ in double-bundle reconstruction group. So, double-bundle reconstruction had better results in both anterior stress radiographs with the $Telos^{(R)}$ device and the maximal manual test with the KT-2000 arthrometer, and there were significant differences in statistics. But, clinical results such as IKDC(International Knee Documentation Committee) scores, OAK(Orthopadische Arbeitsgruppe Knie) scores, thigh circumference and range of motion had no significant difference between two groups. Conclusions: On the basis of stability, the side-to-side anterior laxity of double-bundle ACL reconstruction was significantly better than that of single-bundle reconstruction, although there were no significant differences in the other clinical measures among them.

• Journal of the Korean Arthroscopy Society
• /
• v.12 no.3
• /
• pp.198-204
• /
• 2008

Purpose: The purpose of this study is to analyze the merits and demerits of double bundle reconstruction and achieve improvements hereafter, by comparing the results of double bundle and single bundle reconstruction using tibialis anterior allograft. Materials and Methods: Twenty seven patients were divided to undergo either double bundle(n=14) or single bundle(n=13) reconstruction with tibialis anterior allograft tendon. The evaluation methods were AP laxity with KT-2000 arthrometer, isokinetic knee strength measurements, pivot-shift test, IKDC subjective score, Lysholm knee score, Tegner activity score, radiographic evaluations with postoperative MRI, and second look arthroscopy. Results: Lysholm knee score and Tegner activity score were significantly better in double bundle reconstruction. In pivot-shift test, single bundle reconstruction was evaluated as grade 0 in 10 of the knees, grade 1 in 1, and grade 2 in 2. Double bundle reconstruction was evaluated as grade 0 in 13, and grade 2 in 1. In second look arthroscopy, single bundle was evaluated as excellent in 6 of the knees, fair in 7, anteromedial bundle of double bundle reconstruction was excellent in 13 and fair in 1, and posterolateral bundle was excellent in 4, fair in 9, and poor in 1. There were no significant differences in other evaluations. Conclusion: Favorable outcome may be expected with double bundle reconstruction of ACL. However there are still need for improvement in terms of reconstruction technique and rehabilitation protocol to reduce PL bundle injury.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1998.05a
• /
• pp.532-537
• /
• 1998

Friction factor and two-phase flow frictional multiplier for a CANFLEX bundle are newly developed and presented in this paper. CANFLEX as a 43-element fuel bundle has been developed jointly by AECL/KAERI to provide greater operational flexibility for CANDU reactor operators and designers. Friction factor and two-phase flow frictional multiplier have been developed by using the experimental data of pressure drops obtained from two series of Freon-l34a (R-134a) CHF tests with a string of simulated CANFLEX bundles in a single phase and a two-phase flow conditions. The friction factor for a CANFLRX bundle is found to be about 20 % higher than that of Blasius for a smooth circular pipe. The pressure drop predicted by using the new correlations of friction factor and two-phase frictional multiplier are well agreed with the experimental pressure drop data of CANFLEX bundle within ${\pm}\;5\;%$ error.

• Nuclear Engineering and Technology
• /
• v.28 no.3
• /
• pp.280-289
• /
• 1996

The pressure drop of twelve fuel bundle string in the CANDU-6 fuel channel is equal to the sum of the eleven junction pressure losses, the bundle string entrance and exit pressure losses, the skin friction pressure loss, and other appendage pressure losses, where the junction loss is dependent on the bundle end faces and angular alignments of the junctions. The results of the single junction pressure drop tests in a short rig show that the most probable pressure drop of the eleven junctions was analytically equal to the eleven times of average pressure drop of all the possible single junction pressure drops, and also that the largest and smallest junction pressure drops across the eleven junctions probably occurred only with BA and BB type junctions, respectively, where A and B denote the bundle end sides with an end-plates on which a company monogram is stamped and unstamped, respectively.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.10b
• /
• pp.291-292
• /
• 2003

Although the tensile strength of textile materials are determined by that of their components, it is well known that the tensile strength of fiber bundles and yams is not accurately predicted from that of single-fibers by simple averaging methods or mathematical calculations, because of variations in their strength. Therefore, there have been attempts to interpret the bundle strength from that of its elements by the stochastical approach. (omitted)

• 대한관절경학회:학술대회논문집
• /
• 2006.11a
• /
• pp.89-89
• /
• 2006