Time filter

Source Type

Cho K.S.,Kyungpook National University | Song K.-W.,Pusan National University | Chang G.-S.,FITI Testing and Research Institute
Journal of Rheology | Year: 2010

We have found empirical scaling relations in nonlinear viscoelasticity of poly(ethylene oxide) (PEO) solutions under large amplitude oscillatory shear flow. The scaling relations superpose dimensionless nonlinear viscoelastic functions, such as the normalized amplitudes of elastic and viscous stresses and normalized Fourier intensities, measured at different strain amplitudes and frequencies on a single curve irrespective of the molecular weight and the concentration of the polymer solutions. The scaling relations reveal that the nonlinear viscoelastic functions are functions of dimensionless variable ζ ≡ γo cos δ (ω), where δ is the phase lag of linear viscoelasticity. The validity of our superposition was checked for PEO aqueous solutions under the conditions that concentration: 3


Lee E.-M.,FITI Testing and Research Institute | Gwon S.-Y.,Kyungpook National University | Kim S.-H.,Kyungpook National University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

A (E)-2-(2-(2-(1H-indol-3-yl)vinyl)-4H-chromen-4-ylidene)malononitrile (dye 1) was synthesized and its cation sensing properties in DMSO were investigated by UV-vis spectroscopy. Upon the addition of Hg2+, the solution of dye 1 showed color change and the absorption band shows a formation of a 1:1 dye 1-Hg2+ coordination complex. The dye 1 exhibited high selectivity for Hg2+ as compared with other cations. Interestingly, the dye 1-F- complex also could be recovered by adding Hg2+. We have investigated the ability of complex formation based on the association constant, Kass; the binding ability for the complex formation of dye 1-F- and Hg2+ is greater than that of the dye 1 with F-. © 2013 Elsevier B.V. All rights reserved.


Kim S.-H.,Kyungpook National University | Lee E.M.,FITI Testing and Research Institute | Bae J.-S.,Kyungpook National University
Sen'i Gakkaishi | Year: 2015

Naphthazarin(5,8-dihydroxy-1,4-naphthoquinone) exhibited high selectivity for F-, as compared with CN-, Cl-, Br-, HSO4-, H2PO4-, ClO- and NO3- in DMSO, which was attributed to the formation 1 : 1 complex. Interestingly, the blue color of the naphthazarin-F- complex could be recovered after the addition of Cr3+. We have investigated the ability of complex formation based on the association constant, Kass ; the binding ability for the complex formation of naphthazarin-F- and Cr3+ is much greater in DMSO (Kass =5.3 × 104 M-1) than that of the naphthazarin with F- (Kass =2.0 × 103 M-1). © 2015, Society of Fiber Science and Technology. All rights reserved.


Koo H.J.,FITI Testing and Research Institute | Chang G.S.,FITI Testing and Research Institute | Kim S.H.,Hanyang University | Hahm W.G.,Korea Institute of Industrial Technology | Park S.Y.,HUVIS Corporation
Fibers and Polymers | Year: 2013

Mechanical properties and the long-term degradation properties of the recycled PET yarns are typically lower than the virgin PET yarns due to the contaminants coming from non-PET bottles, labels and caps etc. For environmental reasons, recycling of post-consumer polyester bottles into textile fibers has become commercially attractive. We studied mechanical and chemical recycling processes and examined their effects on yarn properties such as tensile properties, thermal characteristics, hydrolysis and photo-degradation. It was found that the virgin and the chemical recycled yarns with sufficient purification show similar processability, physical and mechanical properties, and long-term degradation behavior. The results provide useful information on recycled PET yarns for processability and serviceability for the high-end use. © 2013 The Korean Fiber Society and Springer Science+Business Media Dordrecht.


Kim H.K.,FITI Testing and Research Institute | Yuu J.,GOLDENPOW Co. | Jeon H.Y.,Inha University
GA 2012 - 5th Asian Regional Conference on Geosynthetics: Geosynthetics for Sustainable Adaptation to Climate Change | Year: 2012

In this study, key properties of polyethylene resin and HDPE GM were tested for comparing their stress crack behaviors. Stress cracking time was differed from each type of resins and products. The failure times of ESCR test were too long compared to SP-NCTL's. The SP-NCTL results of RWOA was failed earlier than RWA's, GM1's and GM2's. But there was no difference between each sample of the results of ESCR test within short term testing duration. The ESCR test was influenced by stress relaxation during the test. The SP-NCTL test is reasonable for verifying stress cracking behavior and construction quality control. According to this study, ESCR test is not appropriate for determining the stress crack behavior, but SP-NCTL test is better test method for predicting the stress crack behaviors of HDPE GM.


Koo H.-J.,FITI Testing and Research Institute | Cho H.-W.,FITI Testing and Research Institute | Oh J.-T.,FITI Testing and Research Institute | Zanzinger H.,SKZ
10th International Conference on Geosynthetics, ICG 2014 | Year: 2014

Geosynthetics for all applications have to be tested for resistance to weathering because polymers are generally degraded under the exposure to UV spectral region. EN 12224 and ASTM D4355 describe accelerated weathering tests with different light sources. EN 12224 is based on the 50 MJ/m2 radiant exposure which is equivalent to one month exposure in southern Europe during summer. There are various approaches to reach the same radiant exposure given in EN 12224. The duration required was 320 h for devices with a combination of fluorescent UV lamps, 350 h for devices with UV-A lamps if the lamps are left on during the water spray and 430 h for devices with UV-A lamps if the lamps are turned off during the water spray. ASTM D4355 uses a Xenon arc light source having a spectrum that simulates natural daylight, including the UV region. In this study, we have performed the accelerated weathering tests according to EN 12224 using combination of fluorescent UV and UV-A lamps, and ASTM D 4355 using conventional weatherometers and investigated the effects of different light sources on degradation properties of non-woven geotextiles. It was found that the two light sources used in EN 12224 show different degradation behaviors due to the larger portion of UV region in UV-A lamp while the combination UV and Xenon arc lamp used in ASTM D4355 show the similar degradation rate on non-woven geotex-tiles. In addition, lamp left on during water spray accelerates the degradation of non-woven geotextiles. The results suggest the necessity for the weathering test method which can simulate the actual degradation behavior in the field.


Han W.-S.,Hanseo University | Lee H.-J.,FITI Testing and Research Institute | Lee J.-S.,National Institute of Environmental Research Complex | Lee Y.-H.,Hanseo University | Hong T.-K.,Hanseo University
Journal of Analytical Chemistry | Year: 2014

A cyanide ion selective poly(aniline) solid contact electrode based on nickel complex of N,N′-bis-(4-phenylazosalicylidene)-o-phenylenediamine ionophore was successfully developed. The electrode exhibits a good linear response of 58.7 mV/decade (at 20 ± 0.2 C, r 2 = 0.998) with in the concentration range of 1 × 10-1.0-1 × 10 -6.0 M cyanide. The composition of this electrode was: ionophore 0.300, polyvinylchloride 0.300, 2-nitrophenyloctyl ether 0.670 (mass). This 2-nitrophenyloctyl ether plasticizer provides the best response characteristics. The electrode shows good selectivity for cyanide ion in comparison with any other anions and is suitable for use with aqueous solutions of pH 4.6-6.3. The standard deviations of the measured emf difference were ±1.92 and ±1.87 mV for cyanide sample solutions of 1.0 × 10-2 M and 1.0 × 10-3 M, respectively. The stabilization time was less than 183 s and response time was less than 38 s. © 2014 Pleiades Publishing, Ltd.


Jin Y.C.,FITI Testing and Research Institute | Jeon H.-Y.,Inha University
10th International Conference on Geosynthetics, ICG 2014 | Year: 2014

Total reduction factor that is used when calculating allowable tensile strength of geogrids is made by multiplying the installation damage reduction factor, chemical degradation reduction factor, and creep reduction factor etc. In this paper, creep property of geogrids was measured by 3 methods such as conventional test, TTS, SIM and the results were compared. All the three methods showed similar behavior but it turned out that it had more strain of SIM method at higher temperature. Reduction factors for creep rupture and limited strain were similar by each method.


Koo H.-J.,FITI Testing and Research Institute | Chang G.-S.,FITI Testing and Research Institute
10th International Conference on Geosynthetics, ICG 2014 | Year: 2014

Prefabricated vertical drains (PVDs) are drainage composites installed vertically into soil to accelerate the settlement of soils under a given surcharge loading. Discharge capacity is, therefore, one of the most important properties for PVDs. According to EN 15237, the relative compression taking place during the consolidation process may cause buckling of the drains which subsequently reduces the discharge capacity. There are many different test methods such as ASTM D 6918, EN 15237, KS K 0940 and RS-FITI-2011-021 for discharge capacity in buckled condition and it is necessary to standardize them as an index test method. In this study, a test method was developed to determine the discharge capacity of PVDs in buckled condition. The PVDs were buckled while maintaining the buckled shape in a fixed format, using a specially designed buckling device. The discharge capacity was measured under 120 kPa of pressure for 7 days under various buckling conditions. The effects of buckling shape, condition and procedure, and fixing pin diameter on discharge capacity were studied using PVDs with various core weights and types to optimize test conditions.


Kim Y.,FITI Testing and Research Institute | Kim Y.,Soongsil University | Kim T.,FITI Testing and Research Institute | Choi H.-M.,Soongsil University
Industrial and Engineering Chemistry Research | Year: 2013

Protein fingerprint analysis using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was investigated for qualitative identification and differentiation of cashmere and yak fibers. Mass spectra of a total of 25 cashmere and 7 yak fibers were obtained and analyzed. Three ion peaks that are specific only to cashmere fiber were identified as m/z 2036, 2634, and 3266. On the other hand, two ion peaks at m/z 2503 and 2519 can be used as fingerprint ions for yak fiber. This test method can be effectively used in differentiating cashmere fiber from yak fibers in the item with a fraudulent label. We hoped that the use of this identification method could reduce the fraudulent labeling problem in the luxury fiber market. © 2013 American Chemical Society.

Loading FITI Testing and Research Institute collaborators
Loading FITI Testing and Research Institute collaborators