• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.7 s.250
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• pp.857-864
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• 2006

Various compressive specimens were fabricated using autoclave do-gassing moulding to find out the compressive characteristics of the carbon/epoxy plain weave fabric composites with respect to the bias and shear angles. The stacking angles of the bias specimens are $[0]_{10T,}\;[3]_{10T,}\;[6]_{10T,}\;[9]_{10T,}\;[12]_{10T,}\;[15]_{10T,}\;[30]_{10T,}\;[45]_{10T}$ and those of the sheared specimens are $[{\pm}37]_{10T,}\;[{\pm}32]_{10T,}\;[{\pm}28]_{10T,}\;[{\pm}22]_{10T,}$ respectively. In order to verify the effect of micro-tow structures on compressive strength and modulus of the composites, compressive test specimens of uni-directional carbon/epoxy composites with the same materials and the same stacking conditions were fabricated. The modulus and strength of both types of composite specimens were compared with the prediction results based on the CLPT and a proposed strength formula. The tow deformation and fracture modes were investigated by microscopic observation.

• Particle and aerosol research
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• v.13 no.1
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• pp.11-16
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• 2017

Indoor air quality is of increasing concern because it is closely related human health. An air handling unit (AHU) can be used to control the indoor air quality related to particulate matters and $CO_2$ as well as air conditioning such as temperature and humidity of indoor air. An electrostatic precipitator has a high collection efficiency and low pressure drop, however, ozone can possibly generate from its chargers, which is one of drawbacks to apply it for indoor air control. Here we compared four charging electrodes such as a $50{\mu}m$ tungsten wire, a $100{\mu}m$ tungsten wire, a $16{\mu}m$-thickness Al foil and a carbon fabric comprised of $5-10{\mu}m$ fibers. The carbon fabric electrode showed a superior particle collection efficiency and a lower ozone generation at a given power consumption compared to tungsten wires of 50, $100{\mu}m$ and an Al foil electrode. This low ozone generating, micro-sized electrode can be applied to the electrostatic precipitator in AHU for indoor air control.

• Polymer(Korea)
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• v.33 no.6
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• pp.575-580
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• 2009

Carbon fabric-reinforced silicon carbide composites (C/SiC) have attracted a considerable attention for high temperature structural application because of their outstanding oxidation resistance property and thermal shock resistance. In this study, we reported on the preparation of C/SiC composites by the polymer impregnation and pyrolysis (PIP) method. For this, polycarbosilane solution was impregnated into the carbon fabric and then cured by electron beam irradiation under argon atmosphere. Afterwards, the cured composite was pyrolyzed at $1300^{\circ}C$ for 1 h under argon atmosphere to produce the C/SiC composite. The porosity and density of the C/SiC composite were 13.5% and $2.44\;g/cm^3$, respectively, when the impregnation of the carbon fabric with the 30 wt% polycarbosilane solution conducted four times. In addition, in the isothermal experiment at $1500\;^{\circ}C$ in air for 5 h, the 95.9 wt% of the C/SiC composite was remained, indicating that the prepared C/SiC composite has a outstanding oxidation resistance.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.466-473
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• 2020

Fabric current collector can be a promising electrode material for Capacitive Deionization (CDI) system that can achieve energy-efficient desalination of water. The one of the most attractive feature of the fabric current collector is its high tensile strength, which can be an alternative to the low mechanical strength of the graphite foil electrode. Another advantage is that the textile properties can easily make shapes by simple cutting, and the porosity and inter-fiber space which can assist facile flow of the aqueous medium. The fibers used in this study were made of woven structures using a spinning yarn using conductive LM fiber and carbon fiber, with tensile strength of 319 MPa, about 60 times stronger than graphite foil. The results were analyzed by measuring the salt removal efficiency by changing the viscosity of electrode slurry, adsorption voltage, flow rate of the aqueous medium, and concentration of the aqueous medium. Under the conditions of NaCl 200 mg/L, 20ml/min and adsorption voltage 1.5 V, salt removal efficiency of 43.9% in unit cells and 59.8% in modules stacked with 100 cells were shown, respectively. In unit cells, salt removal efficiency increases as the adsorption voltage increase to 1.3, 1.4 and 1.5 V. However, increasing to 1.6 and 1.7 V reduced salt removal efficiency. However, the 100-cell-stacked module showed a moderate increase in salt removal efficiency even at voltages above 1.5 V. The salt removal rate decreased when the flow rate of the feed was increased, and the salt removal rate decreased when the concentration of the feed was increased. This work shows that fabric current collector can be an alternative of a graphite foil.

• Science of Emotion and Sensibility
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• v.24 no.4
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• pp.129-138
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• 2021

This study aimed to determine the effects of the shape and attachment position of stretchable textile sensors coated with carbon nanotube on their performance when used to measure children's joint movements. Moreover, the child-safe requirements for fabric motion sensors are established. The child participants were advised to wear integrated clothing equipped with the sensors of various shapes (rectangular and boat-shaped) and attachment positions (at the knee and elbow joints or 4 cm below the joints). The voltage change induced by the elongation and contraction of the fabric sensors was determined for arm and leg flexion-extension motions at 60 deg/s (three measurements of 10 repeats each for 60°and 90°angles, for a total of 60 repetitions). Their dependability was determined by comparing the fabric motion sensors to the associated acceleration sensors. The experimental results indicate that the rectangular-shaped sensor affixed 4 cm below the joint is the most effective fabric motion sensor for measuring children's arm and leg motions. In this study, we designed a textile sensor capable of tracking children's joint motion and analyzed the sensor shape and attachment position on motion sensing clothing. We demonstrated that flexible fabric sensors integrated into garments may be used to detect the joint motions of the human body.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.540-547
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• 2021

Background: Indoor air pollutants are caused by a number of factors, such as coming in from the outside or being generated by internal activities. Typical indoor air pollutants include nitrogen dioxide and carbon monoxide from household items such as heating appliances and volatile organic compounds from building materials. In addition there is carbon dioxide from human breathing and bacteria from speaking, coughing, and sneezing. Objectives: According to recent research results, most indoor air pollution is known to be greatly affected by internal factors such as burning (biomass for cooking) and various pollutants. These pollutants can have a fatal effect on the human body due to a lack of ventilation facilities. Methods: We fabricated a polydopamine (PDA) layer with Ti substrates as a coating on supported glass fiber fabric to enhance its photo-activity. The PDA layer with TiO₂ was covalently attached to glass fiber fabric using the drop-casting method. The roughness and functional groups of the surface of the Ti substrate/PDA coated glass fiber fabric were verified through infrared imaging microscopy and field emission scanning electron microscopy (FE-SEM). The obtained hybrid Ti substrate/PDA coated glass fiber fabric was investigated for photocatalytic activity by the removal of ammonia and an epidermal Staphylococcus aureus reduction test with lamp (250 nm, 405 nm wavelength) at 24℃. Results: Antibacterial properties were found to reduce epidermal staphylococcus aureus in the Ti substrate/PDA coated glass fiber fabric under 405 nm after three hours. In addition, the Ti substrate/PDA coated glass fiber fabric of VOC reduction rate for ammonia was 50% under 405 nm after 30 min. Conclusions: An electron-hole pair due to photoexcitation is generated in the PDA layer and transferred to the conduction band of TiO₂. This generates a superoxide radical that degrades ammonia and removes epidermal Staphylococcus aureus.

• Carbon letters
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• v.12 no.4
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• pp.249-251
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• 2011

Carbon/epoxy woven composites are prominent wear-resistant materials due to the strength, stiffness, and thermal conductivity of carbon fabric. In this study, the effect of oilabsorption on the wear behaviors of carbon/epoxy woven composites was investigated. Wear tests were performed on dry and fully oil-absorbed carbon/epoxy woven composites. The worn surfaces of the test specimens were examined via scanning electron microscopy to investigate the wear mechanisms of oil-absorbed carbon/epoxy woven composites. It was found that the oil absorption rate was 0.14% when the carbon/epoxy woven composites were fully saturated. In addition, the wear properties of the carbon/epoxy woven composites were found to be affected by oilabsorption. Specifically, the friction coefficients of dry and oil-absorbed carbon/epoxy woven composites were 0.25-0.30 and 0.55-0.6, respectively. The wear loss of the oilabsorbed carbon/epoxy woven composites was $3.52{\times}10^{-2}\;cm^3$, while that of the dry carbon/epoxy woven composites was $3.52{\times}10^{-2}\;cm^3$. SEM results revealed that the higher friction coefficient and wear loss of the oil-absorbed carbon/epoxy woven composites can be attributed to the existence of broken and randomly dispersed fibers due to the weak adhesion forces between the carbon fibers and the epoxy matrix.

• Composites Research
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• v.14 no.6
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• pp.38-46
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• 2001

In this study, An optimization code that can design microwave absorbing composite laminates is developed, and 3-layered microwave absorbing composite laminates are developed by optimizing the thickness of each layer. The layers are 3 different composite laminates. Many variables including lay-up angles of electromagnetically orthotropic composite layer can be considered in this code. The developed laminate is composed of an impedance matching layer of glass/epoxy fabric laminate, a glass/epoxy fabric laminate layer containing aluminum filler and carbon/epoxy fabric laminate layer. Permittivities of the materials are obtained using a network analyzer and a coaxial air line.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.49-54
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• 2005

Recently, many kinds of advanced composite materials have been used in various industry fields. Among them, fabric CFRP composites are being used as primary structural components in many applications because of their superior properties. However, the complexity of the fabric structure makes understanding of their failure behavior very difficult. The mechanical strength and crack propagation of plain woven carbon fiber fabric laminate composites are examined by acoustic emission(AE) method. AE signals are acquired during the tensile test and fracture tests. Thus, the relationship between AE signal and mechanical behavior curves and crack extension length are shown. Also the interlaminar fracture toughness in terms of AE characteristics are discussed in viewpoint of crack propagation behavior.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.51-54
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• 2004

Testing methods for mechanical properties of the advanced composites were introduced. The mechanical properties, such as tensile properties, compressive properties, in-plane shear properties, flexural properties, and interlaminar shear properties, were evaluated along the warp and the fill directions. The CF3327 of the carbon fabric, the HG1581 of the glass fabric, and the HK285 of the aramid fabric were considered as reinforcements. Epoxy and phenolic resin were used as resin. The experimental results obtained in this study would be applicable in the design and structural analysis for the manufacture of the carbody of the tilting train.