• The Research Journal of the Costume Culture
• /
• v.12 no.6 s.53
• /
• pp.945-952
• /
• 2004

Shrink-resist effects and properties of the knitted fabrics from wool/acrylic(W/A) fiber blends were determined to find out an optimal blending ratio keeping the quality properties of wool products. The test fabrics were knitted by a weft knitting machine with all needle knitting structure ($0{\times}0$ rib) under the same knitting conditions with five different types of yarns: $W100\%,\;A100\%$, and W/A blended yarns(70/30, 50/50, 30/70). Shrinkage during repeated washing, electrostatic propensity, thermal resistance and pilling propensity of W/A knits. The shrink resistance was significantly enhanced on repeated washing of W/A knits, especially, over $50\%$ acrylic blended knits. Addition of strong physical force and alkali detergent applied in this washing experiment brought about superior effects with the low shrinkage rate although it was very severe washing conditions for wool fabrics. The results from the washing experiment implies that W/A blend knits can be machine washed at individual households with other ordinary laundry. There was some changes and variation found in thermal resistance, electrostatic propensity, and pilling. W/A 50/50 blended knits did not bring serious changes to other physical properties comparing with original wool, which helps consumers care wool knitted clothes more conveniently.

• Journal of Ocean Engineering and Technology
• /
• v.22 no.6
• /
• pp.83-87
• /
• 2008

Although a great deal of research has been carried out to solve the plate forming problem and to improve the effectiveness and productivity of the plate forming process, no practical way of automating the plate forming process has been proposed yet. Since characteristics of heating machines may vary, it is necessary to investigate the thermal deformation characteristics of the heating machine that will be used in the automation system its characteristics may be modified as new information about thermal deformation by heating becomes available. In this paper, experiments for line heating have been carried out to calculate the formula of predicting thermal deformation due to line heating with varying affecting parameters, and numerical study has been carried out to produce data beyond the range where a line heating test is impractical. Formulas of predicting transverse distortion and shrinkage have been proposed and derived, based on the present experimental and numerical works. This paper also illustrates how the formula has been modified as new experimental data are added.

• Carbon letters
• /
• v.9 no.4
• /
• pp.308-315
• /
• 2008

In the present study, fast isothermal stabilization processes for rayon precursor fabrics were performed at $350^{\circ}C$ and $400^{\circ}C$ within 3 minutes and the chemical and physical characteristics of the stabilized fabrics were investigated. In addition, rayon precursor fabrics were pre-treated with three different phosphorous-based flame retardants and then stabilized. The effect of flame retardants on the chemical composition, thermal shrinkage, weight change, thermal stability and XRD results was examined, comparing with those of the precursor fabrics. The result showed that the stabilization of rayon fabrics was most effective as the stabilization temperature was $350^{\circ}C$, the stabilization time was 3 min, and the pre-treatment with phosphoric acid of 1 vol%. The carbon contents of stabilized rayon fabrics were increased with increasing stabilization temperature and time, whereas the oxygen contents were decreased. Also, it is likely that the pre-treatment with phosphoric acid plays a role in retarding the change of chemical structure of rayon fabric. The XRD result was quite consistent with the result showing the effect of phosphoric acid on the chemical composition, thermal shrinkage and weight reduction of rayon fabric.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.55 no.5
• /
• pp.223-230
• /
• 2006

The reliability of imprint patterns molded by stamps for industrial application of nanoimprint lithography (NIL), is an important issue. Usually, defects can be produced by incomplete filling of negative patterns and the shrinkage phenomenon of polymers in conventional NIL. In this paper, the patterns that undergo a varied temperature or varied pressure period during the thermal NIL process have been investigated, with the goal of resolving the shrinkage and defective filling problems of polymers. The effects on the formation of polymer patterns in several profiles of imprint processes are also studied. Consequently, it is observed that more precise patterns are formed by the varied temperature (VT-NIL) or varied pressure (VP-NIL). The NIL (VT-NIL or VP-NIL) process has a free space compensation effect on the polymers in stamp cavities. From the results of the experiments, the polymer's filling capability can be improved. The VT-NIL is merged with the VP-NIL for the better filling property. The patterns that have been imprinted in the merged NIL are compared with the results of conventional NIL. In this study, the improvement in the reliability for results of thermal NIL has been achieved.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2002.05a
• /
• pp.7-12
• /
• 2002

The purpose of this study is to design and to apply the self-compaction concrete mixture to field, having not only high strength but also compensation for shrinkage without thermal crack under 4 sides outer restraint of the member. In the experimental mix, replacement ratio of limestone Powder, CSA expansive additives, and unit water were selected as parameters, using portland blast-furnace slag cement. And, bleeding test, expansibility test, hydration heat analysis were performed. As a results, when Cement is replaced with 35% limestone Powder, 6% CSA expansive additives at unit water 175kg/$m^3$, demanded performances of fresh and hardened self-compaction concrete are accomplished in the field application.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.332-335
• /
• 2004

Polymethyl Methacrylate(PMMA) mortars using EPS solution-based binders are prepared with various unsaturated polyester resin(UP) contents of binder, and tested for working life. heat exothorm temperature, length change. compressive strength and temperature dependence of compressive strength. As a result, the working life of PMMA mortar is lengthened with raising UP content of binder. Length change of the mortar was condensed from expansion to shrinkage with increasing UP content, and non shrinkage of the mortar is obtained at about UP content of $2.5\%$. The compressive strength of the mortar is increased with an increase in the UP content and reach maximum at UP content of $5\%$. However thermal resistance improvement of the mortar by increasing UP content was not recognized. UP resin was recommended as an effective agent for shrinkage control and strength development of PMMA mortar.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05b
• /
• pp.657-660
• /
• 2006

Recently, very-early strength latex-modified concrete(below ; VES-LMC) has been developed for repairing and overlaying the old concrete bridge deck. Early-age defects in high-performance concrete due to thermal and autogenous deformation shorten the life cycle of concrete structures. Thus, it is necessary to examine the behavior of early-age concrete at the stages of design and construction. The purpose of this study was to evaluate the autogenous shrinkage of VES-LMC, having an experimental variables such as retarder and water-cement ratio. The greater the retarder content in VES-LMC, the greater the expansion at early-age. This recommend the small retarder content as possible. The effect of water-cement ratio on early-age behavior is very small, because of the wrapped specimen in order to prevent water evaporation.

• Journal of the Korean Ceramic Society
• /
• v.19 no.3
• /
• pp.241-249
• /
• 1982

Two dinnerware porcelain bodies involving partial replacement of feldspar and kaoline by about 35wt% domestic GYUNGJU-pottery stone were developed and their properties such as shrinkage, porosity, firing range, linear thermal expansion, pyroplastic deformation, degree of whiteness and mechanical strength were compared with those of a traditional clay-flint-feldspar body. The experimental results showed that one of the clay-flint-feldspar-pottery stone body with 1% ZnO addition had the firing range of 115$0^{\circ}C$~121$0^{\circ}C$, whereas the traditional body had the firing range of 12$25^{\circ}C$~129$0^{\circ}C$. The linear drying shrinkage and linear dry-to-fired shrinkage of all bodies were 2.5~4.5% and 15~18%, respectively. And the major crystalline phases of sintered bodies were $\alpha$-quartz and secondary mullite surrounded by glassy phases. The modulus of rutpture of sintered bodies was ranged from 860 to 870kg/$\textrm{cm}^2$, and the microhardness of sintered bodies was 680 kg/$\textrm{cm}^2$.

• Computers and Concrete
• /
• v.21 no.3
• /
• pp.279-289
• /
• 2018

Hydration heat and thermal induced cracking have always been a fatal problem for massive concrete structures. In order to study a massive reinforced concrete wall of a storage tank for liquefied natural gas (LNG) during its construction, two mock-ups of $0.8m{\times}0.8m{\times}0.8m$ without and with metal corrugated pipes were designed based on the actual wall construction plan. Temperature distribution and strain development of both mock-ups were measured and compared inside and on the surface of them. Meanwhile, time-dependent thermal and mechanical properties of the concrete were tested standardly and introduced into the finite-element (FE) software with a proposed hydration degree model. According to the comparison results, the FE simulation of temperature field agreed well with the measured data. Besides, the maximum temperature rise was slightly higher and the shrinkage was generally larger in the mock-up without pipes, indicating that corrugated pipes could reduce concrete temperature and decrease shrinkage of surrounding concrete. In addition, the cooling rate decreased approximately linearly with the reduction of heat transfer coefficient h, implying that a target cooling curve can be achieved by calculating a desired coefficient h. Moreover, the maximum cooling rate did not necessarily decrease with the extension of demoulding time. It is better to remove the formwork at least after 116 hours after concrete casting, which promises lower risk of thermal cracking of early-age concrete.

• Applied Chemistry for Engineering
• /
• v.10 no.7
• /
• pp.990-995
• /
• 1999

To determine the effect of chemical structure of linear amine curing agents on thermal and mechanical properties, standard epoxy resin DGEBA was cured with ethylene diamine(EDA) and hexamethylene diamine(HMDA) in a stoichiometrically equivalent ratio. From this work, the effect of linear amine curing agents on the thermal and mechanical properties is significantly influenced by the chemical structure or chain length of curing agents. In contrast, the results show that the DGEBA/EDA system having the two carbons had higher values in the thermal stability, maximum conversion of epoxide, density, glass transition temperature, tensile modulus, flexural strength, and flexural modulus than the DGEBA/HMDA system having the six carbons, whereas the DGEBA/EDA cure system had relatively low values in the shrinkage(%), thermal expansion coefficient, tensile strength, and had similar values in the maximum exothermic temperature, and conversion of epoxide compared to the DGEBA/HMDA cure system. This findings indicate that packing ability in the HMDA structure affects the thermal and mechanical properties.