• Title/Summary/Keyword: Spinning

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Fabrication and Applications of Carbon Nanotube Fibers

  • Choo, Hungo;Jung, Yeonsu;Jeong, Youngjin;Kim, Hwan Chul;Ku, Bon-Cheol
    • Carbon letters
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    • v.13 no.4
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    • pp.191-204
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    • 2012
  • Carbon nanotubes (CNTs) have exceptional mechanical, electrical, and thermal properties compared with those of commercialized high-performance fibers. For use in the form of fabrics that can maintain such properties, individual CNTs should be held together in fibers or made into yarns twisted out of the fibers. Typical methods that are used for such purposes include (a) surfactant-based coagulation spinning, which injects a polymeric binder between CNTs to form fibers; (b) liquid-crystalline spinning, which uses the nature of CNTs to form liquid crystals under certain conditions; (c) direct spinning, which can produce CNT fibers or yarns at the same time as synthesis by introducing a carbon source into a vertical furnace; and (d) forest spinning, which draws and twists CNTs grown vertically on a substrate. However, it is difficult for those CNT fibers to express the excellent properties of individual CNTs as they are. As solutions to this problem, post-treatment processes are under development for improving the production process of CNT fibers or enhancing their properties. This paper discusses the recent methods of fabricating CNT fibers and examines some post-treatment processes for property enhancement and their applications.

Sensitivity analysis of melt spinning process by frequency response

  • Hyun, Jae-Chun;Jung, Hyun-Wook;Lee, Joo-Sung
    • Korea-Australia Rheology Journal
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    • v.14 no.2
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    • pp.57-62
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    • 2002
  • The sensitivity of the final filament to the ongoing sinusoidal disturbances has been Investigated in the viscoelastic spinning using frequency response method. Amplification ratios or gains of the spinline cross-sectional area at the take-up to any disturbances show resonant peaks along the frequency regime, where the frequencies at theme points directly correspond to the imaginary parts of the successive leading eigenvalues from the linear stability analysis. As shown in Jung et al. (1999) and Lee et al (2001), the sensitivity results on the effect of various process conditions such as spinline cooling and fluid viscoelasticity, obtained by dynamic transient simulation have been corroborated in this study. That is, increasing spinline cooling makes the system less sensitive to disturbances, thus stabilizes the spinning. Also, an increasing viscoelasticity for extension-thickening fluids decreases the sensitivity of the spinning. i.e., stabilizing the system, where, as it increases the sensitivity of the spinning of extension-thinning fluids. Furthermore, it has been found in the present study that the inertia force as one of secondary forces causes the system to be more stabile or less sensitive to process disturbances.

Development of the Wheel Disc Spinning Machine (휠 디스크 스피닝 성형기 개발)

  • Kang, Jung-Sik;Kang, E-Sok;Lee, Hang-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.6
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    • pp.58-65
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    • 1999
  • The spinning machine has been developed for a bus and truck wheel disc which is manufactured by spinning process method. This machine has the mechanical structure with bed, 2-column, cross head, 2-vertical slide, 2-horizontal slide with forming roller, clamp slide and main spindle similar to large size vertical lathe. Main spindle attached the mandrel is rotated about 500rpm drived by 280kW power DC motor, and a rotating black material pressed on the mandrel with the clamp slide is spinformed by 2-forming rollers which are attached inner end of the 2-horizontal slides. The 2-vertical and 2-horizontal slides are actuated by the hydraulic cylinder which is controlled by the servo valve individially, and these servo valves are controlled by control signal of the CNC controller which is computed with position signal feedbacked from the encoder sensor. The developed machine can manufacture wheel disc of various section profile without mandrel change because section profile is easily modified using program editing in the CNC controller processor. The wheel disc manufactured by spinning process method has many advantages that the endurance is increased by 2 times and the weight is decreased by 30% compared with a conventional disc.

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A Gyro-Free INS Algorithm in the Navigation Frame and Its Application to the Spinning Vehicle with High Rotation Rate

  • Lee, Junhak;Kim, Heyone;Oh, Sang Heon;Do, Jae Chul;Nam, Chang Woo;Hwang, Dong-Hwan;Lee, Sang Jeong
    • Journal of Positioning, Navigation, and Timing
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    • v.7 no.2
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    • pp.91-103
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    • 2018
  • Conventional inertial measurement units cannot be used in the spinning vehicle with high rotation rate due to gyro's narrow operation range. By the way, angular acceleration can be measured using the accelerometer array distributed in the vehicle. This paper derives a mechanization for the gyro-free INS in the navigation frame, and proposes a gyro-free INS algorithm based on the derived mechanization. In addition, the proposed algorithm is used to estimate angular velocity, attitude, velocity, and position of a spinning vehicle with high rotation rate. A MATLAB-based software platform is configured in order to show validation of the proposed algorithm. The reference trajectory of a spinning vehicle at 3 round per second, 30 round per second are set up, and the outputs of accelerometer are generated when triads of accelerometer are located at the origin and all the axes. Navigation results of the proposed algorithm for the generated output are presented. The results show that the proposed navigation algorithm can be applied to the spinning vehicle with high rotation rate.

A Study on the Thermal Characteristics of Spindle for the Spinning Machine (스피닝 머신용 대형주축의 열특성에 관한 연구)

  • Jeong D.S.;Kim S.T.;Choi D.B.;Ye S.B.;Seol S.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.555-559
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    • 2005
  • Spinning process is a chipless metal forming method for axis-symmetric parts, which is more economical, efficient and versatile method for producing parts than other sheet metal forming process such as stamping or deep drawing. The large-sized spindle for spinning machine is the equipment to ferm a high-pressure vessel into the demanded shape. The important problem in the spindle system fur spinning machines is to reduce and minimize the thermal effect by motor and bearings. In this study, the effect of heat generation of bearings for the large-sized spindle is considered. Temperature distribution and thermal displacement of the spindle system for spinning machine can be analyzed by using the finite element method. The numerical results are compared with the measured data. The results show that temperature distribution and thermal displacement can be reasonably estimated by using the finite element method and the three dimensional model.

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Effect of Pesticide Residue in Soil on Silkworm, Bombyx Mori L- Survey Analysis

  • Jyothi, N.B.;Prashant, N. Bavachikar;Maribashetty, V.G.;Radhakrishna, P.G.
    • International Journal of Industrial Entomology and Biomaterials
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    • v.38 no.2
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    • pp.31-37
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    • 2019
  • Silkworm larval mortality specifically during spinning stage leading to non-spinning with specific morphological symptoms was frequently complained by sericulturists in Karnataka, India during 2015. Survey was conducted and information collected through questionnaire from the identified farmers who faced the problem of non-spinning in both traditional and non-traditional areas of Karnataka. Survey results indicate that the problem is specific to the silkworm crop of those farmers' who shifted from other crops of agriculture/ horticulture/olericulture/ floriculture to Sericulture. Silkworm rearing performance of the batches fed with these leaves confirmed that the pesticide sprayed to the crops previous to mulberry, remain in the soil and when mulberry plantation is taken up in these gardens, the pesticide is absorbed by the roots of mulberry plants and transported to the leaves. Silkworms that feed on these mulberry leaves, grow and ripen normally but during spinning stage, larvae die with external symptoms like regurgitation, body shrinkage, rectal protrusion later become hook shaped leading to non-spinning or partial metamorphosis into pupa and death or spin flimsy cocoons. Larval mortality ranged from a minimum of twenty five percent to a maximum of hundred percent. The problem was noticed from the first harvest of leaves and lasted for a maximum period of 36 months. Cocoon crop loss depends on the concentration, duration and type of pesticides used previously for other crops.

Resonance behavior of functionally graded carbon nanotube-reinforced composites shells with spinning motion and axial motion

  • Jia-Qin Xu;Gui-Lin She
    • Steel and Composite Structures
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    • v.49 no.3
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    • pp.325-335
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    • 2023
  • The missile is affected by both spinning and axial motion during its movement, which will have a very adverse impact on the stability and reliability of the missile. This paper regards missiles as cylindrical shell structures with spinning and axial motion. In this article, the forced vibration of carbon nanotube-reinforced composites (CNTRCs) cylindrical shells with spinning motion and axial motion is investigated, in which the clamped-clamped and simply-simply supported boundary conditions are considered. The displacement field is described by the first-order shear theory, and the vibration equation is deduced by using the Euler-Lagrange equation, after dimensionless processing, the dimensionless equation of motion is obtained. The correctness of this paper is verified by comparing with the results of the existing literature, in which the simply-simply supported ends are taken into account. In the end, the effects of different parameters such as spinning velocity, axial velocity, carbon nanotube volume fraction, length thickness ratio and load position on the resonance behavior of cylindrical shells are given. It can be found that these parameters can significantly change the resonance of axially moving and rotating moving CNTRCs cylindrical shells.

Parametric resonance of a spinning graphene-based composite shaft considering the gyroscopic effect

  • Neda Asadi;Hadi Arvin;Yaghoub Tadi Beni;Krzysztof Kamil Zur
    • Steel and Composite Structures
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    • v.51 no.4
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    • pp.457-471
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    • 2024
  • In this research, for the first time the instability boundaries for a spinning shaft reinforced with graphene nanoplatelets undergone the principle parametric resonance are determined and examined taking into account the gyroscopic effect. In this respect, the extracted equations of motion in our previous research (Ref. Asadi et al. (2023)) are implemented and efficiently upgraded. In the upgraded discretized equations the effect of the Rayleigh's damping and the varying spinning speed is included that leads to a different dynamical discretized governing equations. The previous research was about the free vibration analysis of spinning graphene-based shafts examined by an eigen-value problem analysis; while, in the current research an advanced mechanical analysis is addressed in details for the first time that is the dynamics instability of the aforementioned shaft subjected to the principal parametric resonance. The spinning speed of the shaft is considered to be varied harmonically as a function of time. Rayleigh's damping effect is applied to the governing equations in order to regard the energy loss of the system. Resorting to Bolotin's route, Floquet theory and β-Newmark method, the instability region and its accompanied boundaries are defined. Accordingly, the effects of the graphene nanoplatelet on the instability region are elucidated.

A Prediction Study on the Roll Lock-in Phenomena of Freely Spinning Tailfins (자유회전 테일핀의 Roll Lock-in 현상 예측 연구)

  • Yang, Young-Rok;Cho, Tae-Hwan;Myong, Rho-Shin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.9
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    • pp.849-855
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    • 2010
  • This paper investigated the roll lock-in phenomena of a canard-controlled missile with freely spinning tailfins by applying Falanga's roll-rate equation. To confirm and validate the accuracy of the results of the roll-rate and roll lock-in prediction for freely spinning tailfins, the results were compared with Blair's wind tunnel test data. For calculation of the roll-rate of freely spinning tailfins, rolling moment coefficients of the tailfins were obtained from the wind tunnel test data and roll-damping coefficients were calculated by missile DATCOM. The roll-rate and roll lock-in of the freely spinning tailfins were calculated by applying these values to the roll-rate equation for freely spinning tailfins. The calculation results showed good agreement with the wind tunnel test data, and the roll lock-in could be anticipated as well.

Studies on the Melting Characterization of Basalt and its Continuous Fiber Spinning (현무암의 용융특성과 연속섬유 방사 연구)

  • Park, Hye-Jung;Park, Sun-Min;Lee, Jae-Won;Roh, Gwang-Chul;Kim, Jae-Keun
    • Composites Research
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    • v.23 no.3
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    • pp.43-49
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    • 2010
  • Basaltic fiber was prepared by continuous spinning process from Jeju Pyosun raw basalt materials. First, for confirming the melting characterization of basalt, basalt raw material put into Pt crucible and melted up to $1550^{\circ}C$ then quenched by dropping it into water. After quenching, the optimum fiber spinning conditions were investigated by measurement and analysis of XRD, TMA, high temperature viscosity, high temperature conductivity and high temperature microscope. The optimum spinning temperature and viscosity for preparation of continuous filament fiber were $1264^{\circ}C$ and $10^{2.8}$ poise at $1264^{\circ}C$, respectively. Properties of prepared spinning fiber were confirmed by tensile strength, FE-SEM, heat resisting test and others. The tensile strength of fiber prepared by spinning conditions of the bushing temperature $1240^{\circ}C$ and winder speed 4600rpm was 3660MPa.