• Journal of the Korean Society for Heat Treatment
• /
• v.15 no.5
• /
• pp.228-233
• /
• 2002

The characteristics of the induction heating process are analyzed for the joint of nylon and metal. The temperature of metal surface is measured using thermocouples. The relations of temperature and induction heating parameters are analyzed. Heat equation models are constructed and the temperature distribution is predicted using Fluent. The effects of heating parameters on the joint strength are evaluated. Finally, the optimal parameters of induction heating process are proposed as 16kW and 6 seconds.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.931-932
• /
• 2007

Specially, High Temperature Superconducting power-transmission cable(HTS cable), 3-phase 100m long, 22.9kV class HTS power transmission cable system have been developed by Korea Electrotechnology Research Institute (KERI) and LS cable Ltd. that is one of 21st century frontier project in Korea. This cable was installed in KEPCO(Go-chang) testing site. In case of manufacturing HTS cable, superconducting joint is very important because they need very long tapes. Therefore, this paper gives some investigation of AC Loss in joined HTS tape by using several joint methods. Finally, this paper was shown background data for the form of HTS cable joint.

• Journal of the Korean Society for Heat Treatment
• /
• v.29 no.1
• /
• pp.1-7
• /
• 2016

Titanium and its alloys can be usually joined with brazing method. And the alloys should be brazed at low temperature to keep their original microstructure. In this study, the mechanical strength and microstructure of the CP-Ti joint-brazed with $Zr_{54}Ti_{22}Ni_{16}Cu_8$ filler metal having melting temperature of $774{\sim}783^{\circ}C$ were investigated. The tensile strengths of the joint-brazed at $800^{\circ}C$ with $100^{\circ}C/min$ of cooling rate showed more than 400 MPa which was as high as base metal. The $Widmanst{\ddot{a}}tten$ structure consisting of Ti and $Ti_2Ni$ phase was observed in the joint area. However, the tensile strengths of the joint-brazed at $800^{\circ}C$ with $15^{\circ}C/min$ of cooling rate were decreased and the Ti, $(Ti,Zr)_2Ni$ and $Ti_2Ni$ phases were observed at the joint area. It is believed that the $(Ti,Zr)_2Ni$ laves phases could decrease the mechanical strength of the joint and the cooling rate should be controled to get high strength of the titanium joint.

• Journal of Welding and Joining
• /
• v.17 no.3
• /
• pp.79-89
• /
• 1999

The study was carried out to examine in more detail metallurgical and mechanical properties of brazed joints of diamond cutting wheel. In this work, shank(mild steel) and sintered bronze-base tips were brazed with three different filler materials(W-40, BAgl and BAg3S). The machine used in this work was a high frequency induction brazing equipment. The joint thickness, porosities and microstructure of brazed joints with brazing variables(brazing temperature, holding time) were evaluated with OLM, SEM, EDS and XRD. Bending(torque) test was also performed to evaluate strength of brazed joints. Further wetting test was performed in a vacuum furnace in order to evaluate the wettability of filler metals on base metals9shank and tips). The brazing temperature had a strong influence on the joint strength and the optimum brazing temperature range was about $700~850^{\circ}C$ for the bronze/steel combinations. The strength of the brazed joint was found to be influenced by the three factors : degree of reaction region, porosity content, joint thickness. The reaction region was formed in the bronze-base tip adjacent to the joint. The reaction region resulted in a bad influence on the strength due to the formation of Cu5.6Sn, CuZn4, $\beta(CuZn)$ and CdAg, etc. Porosities increased as brazing variables(brazing temperature, holding time) increased, and the brazed joints with porosities of less than about 3-5% had an optimum strength for the bronze-base tip.

• Composites Research
• /
• v.24 no.4
• /
• pp.48-54
• /
• 2011

The effect of moisture contents by salt water on the strength of composite single-lap bonded joints is investigated. The specimens were manufactured in an autoclave by secondary bonding and immersed in the 3.5% salt water of $71^{\circ}C$ for different durations to get various moisture contents; 0, 0.2, 0.5, 1.0, and 2.0%(saturation). A total of 80 joint specimens were tested for 5 different moisture contents and 2 temperature environments. Test results show that while the joint strengths after the saturation of moisture decrease compared to those of dry ones, the strengths of the pre-saturated joint up to 1.0% of moisture content increase in both room and elevated temperature conditions. It is also shown that the strengths of joints tested in elevated temperature are slightly higher than the strength in room temperature by 2-5% until the moisture content reaches 1 %. In contrast, the high temperature strength of the saturated joint is about 5% lower than the room temperature strength.

• Journal of Korean Physical Therapy Science
• /
• v.10 no.1
• /
• pp.130-139
• /
• 2003

This study was conducted in order to determine the effect of Paraffin Therapy on release of pain, skin temperature and range of motion with joint diseases. This study was performed on 42 patients with general joint diseases and 21 patients with degenerative joint diseases. All the subjects were randomly assigned to three groups with 21 each. The experiment had been done from June, 1. 2002 to September, 30. 2002, in two general hospitals and a social welfare center using Digital Thermometer Kane-May KM330 and VAS(visual analogue scale). Each pint was measured in terms of skin temperature, pain scale and ROM(range of motion). The results of the experiment are as follows : 1. In application of three different heat modalities (Paraffin bath, Infra red, Hydro pack) on the Knee, Ankle, Elbow pints of the subjects for 30 minutes, the elevation of skin temperature and the reduction of pain scale were found to be significantly different. When checked right after the 30 minutes' application, the Infra red resulted in a higher degree elevation of skin temperature than two other modalities, while Paraffin bath resulted in the highest degree of the elevation of skin temperature when it was checked one hour after the application was over. It means that Paraffin bath lasted longer than the other two modalities(F=14.691, p<.000). 2. With Paraffin bath application, pint pain was reduced significantly both in 30 minutes and one hour checks(F=20.675, p<.001). 3. In terms of ROM(range of motion) increase, didn't seem to have any significant differences in 30 minutes and one hour. The results suggest that Paraffin therapy be helpful in maximizing th effects on pint diseases. I strongly suggest that further studies be done on other pints and muscle diseases using Paraffin bath in different methods of applying the therapy.

• International Journal of Highway Engineering
• /
• v.3 no.1 s.7
• /
• pp.165-176
• /
• 2001

Joints in jointed concrete Pavement are designed to control against randomly occurred cracks within slabs, which may be caused by temperature or moisture variation. The advantage of these artificial cracks (joints) over naturally occurred cracks are easy access of protections, such as installation of joint seal and load transfer mechanism. The potential benefits of joint seals are to prevent infiltration of surface water through the joint into underlying soil and intrusion of incompressible materials (debris, fine size aggregate) in to the joint, which may prevent weakening of underlying soils and spallings due to excessive compressive stress, respectively. For the adequate design of joint seal, horizontal variation of joint widths (horizontal joint movements) are essential inputs. Based on long-term in-situ joint movement data of sixteen jointed concrete pavement sections in Long Term Performance Pavement Seasonal Monitoring Program (LTPP SMP), it was indicated that considerable Portion of joints showed no horizontal movements with change in temperature. This Phenomenon is called 'Joint Freezing'. Possible cause for joint freezing is that designed penetrated cracks do not occur at a joint. In this study, a model for the prediction of the ratio of freezing joints in a particular pavement sections is proposed. In addition, possible effects of joint freezing against pavement performance are addressed.

• The Journal of Korean Physical Therapy
• /
• v.19 no.5
• /
• pp.43-49
• /
• 2007

Purpose: The purpose of this study was to the effects of temporomandibular joint movement restriction on treatment of SCM muscle pain. Methods: The Subjects(n=20) were males(n=7) and females(n=13) that had SCM muscle pain and movement restriction at one side oftemporomandibular joint. The massage and Taping performed on the SCM muscle during 4 weeks. The measured items of SCM pain were pressure-pain scale, DITI. The measured items of temporomandibular joint movement restriction were VAS, ROM, deviation. Results: SCM muscle of pressure-pain scale is lower in ipsilateral than counterlateral, But temperature is higher in ipsilateral than counterlateral. Pressure-pain scale was statistical significance (p<0.05). After studying, the pain and temperature of SCM muscle was decreased and statistical significance(p<0.05). After studying, VAS of Temporomandibular joint was decreased, ROM was increased, deviation was decreased. All of measured items of Before and after studying found a statistical significance(p<0.05). Conclusion: This study showed that SCM muscle pain related TM joint pain and movement restriction. The patient with TM joint movement restriction that may take effect on reducing SCM muscle pain.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.630-633
• /
• 2004

Generally, component and FR-4 board are connected by solder joint. Because material properties of components and FR-4 board are different, component and FR-4 board show different coefficients of thermal expansion (CTE) and thus strains in component and board are different when they are heated. That is, the differences in CTE of component and FR-4 board cause the dissimilarity in shear strain and BGA solder joint s failure. The first order Taylor series expansion of the limit state function incorporating with thermal fatigue models is used in order to estimate the failure probability of solder joints under heated condition. A model based on plastic-strain rate such as the Coffin-Manson Fatigue Model is utilized in this study. The effects of random variables such as frequency, maximum temperature, and temperature variations on the failure probability of the BGA solder joint are systematically investigated by using a failure probability model with the first order reliability method(FORM).

• Journal of Welding and Joining
• /
• v.15 no.2
• /
• pp.36-42
• /
• 1997

In this paper, stability of initial strength at solder joint with lead free solders, such as Sn-In (52-48%) and Sn-Ag (96.5-3.5wt%) was studied. To obtain at solder joint with high quality, it is very important to control the temperature at the interface of solder joints. It is found that the thermal EMF (electro motive force) occurs betwee lead frame and copper pad on a substrate during reflow soldering process using heated tip. As a result of control the temperature at interface of solder joints, variation of initial strength at solder joint decreases from about $\pm40%$ to $\pm20%$, and it is realized Pb free soldering process using Sn/In and Sn-Ag solder paste.