• Design & Manufacturing
• /
• 제14권3호
• /
• pp.37-43
• /
• 2020

Progressive drawing processing is one of the manufacturing processes used to mass-produce a variety of products on the industrial site. In this study, the goal is to achieve a uniform product thickness of at least 1.3mm by reducing the wall thickness of the coupler parts used in automotive air conditioning systems to within 15% using A5052-H32 materials. The progressive die was designed using Blank's law of volume invariance. Due to the characteristics of the drawing process, the material thickness in the punch R part decreases and the thickness in the die R part increases. When designing the progressive die of the coupler part, an ironing method, a push back method, and a stand-alone die pad method were applied to each process to design a mold in consideration of the drawing rate and to artificially adjust the thickness change. The suitability of the method used in die design was investigated by measuring the thickness change of forming parts for each process. In the final part, it was confirmed that the thickness measurement values of the five regions of a radial line were implemented as 1.34-1.36 mm.

• 센서학회지
• /
• 제9권2호
• /
• pp.141-145
• /
• 2000

용강 및 고온슬래그의 현저한 저항차를 이용한 제강용 슬래그 두께 측정시스템을 개발하기 위하여 시험용 저항센서형 검출소자 제작 및 측정시스템을 구성하고 측정실험을 통하여 저항센서형 슬래그 측정시스템의 효율 및 측정정도 측면에 대하여 분석하였다. 분석결과 용강 및 슬래그의 저항차는 $10^3$ order로 확인되었으며 용강 및 슬래그의 이러한 현저한 저항차를 이용하여 고정도로 슬래그 두께를 측정할 수 있음을 보여주었다.

• 한국의류학회지
• /
• 제19권1호
• /
• pp.142-148
• /
• 1995

In this study, FVM (Finite Volume Method) which is one of the 2-dimensional numerical approach has been conducted to anticipate the temperature distribution between skin and clothes by the change of air temperature and fabric characteristics including fabric thickness. Several experimental works have been done to understand the thermal insulation effect (If fabrics on a human body by measuring the averaged temperature in the air layer between skin and clothes or by measuring the thermal resistance of fabrics. However, the formal method is inconvenient to measure the temperature distribution in the air layer to evaluate the insulation rate of the clothes on the skin because the real size of the clearance between skin and the clothes is too small to place the temperature sensor, and in the Tatter method the relationship between human body and the fabrics are ignored. However, the numerical method will be very effective and economical way to evaluate the insulation efficiency of clothes when the computational result is in the reliable range. As the result of this study, the temperature change in the sir layer between skin and clothes was linear to the fabric thickness and this result coincides with many previous experimental results. Moreover, it is possible to predict the optimum fabric thickness for the best thermal insulation in the air layer between skin and clothes.

• 한국안전학회지
• /
• 제10권4호
• /
• pp.47-59
• /
• 1995

The perchlorate, thiocyanate, and nitrate ion-selective PVC membrance electrode for measuring hazardous anion in waste water were developed by incorporating the quaternary ammonium salts as active material. Ion-selective characteristics in waste water were studied by the useful pH range, the selective coefficients to various interfering anions, and the stability of electrode potential. DBP was best as a plasticizer. The effect of the membrane thickness on the electrode characteristics was improved with decreasing the membrane thickness, but below the optimum membrane thickness the electrode exhibited an inverse trend. The electrode potential of perchlorate, thiocyanate, and nitrate electrode with TDDA, as active material, was stable within the pH range 4-11, 3-12, and 4-10 repectively. And the long-term potential stability of these electrodes were 3.0, 3.5, and 3.5 months respectively. The order of the selectivity coefficients was as shown below ; $ClO_4{^-}$ > $SCN^-$ > $I^-$ > $NO_3{^-}$ > $Br^-$ > $CN^-$ > $F^-$ > $Cl^-$ > $Ac^-$ > $H_2PO_4{^-}$, $SO_4{^-}$.

• 센서학회지
• /
• 제25권1호
• /
• pp.57-64
• /
• 2016

To understand a two-phase flow, a liquid film thickness is one of the important factors. A lot of researches have been performed to measure liquid film thickness with various approaches. Recently, an electrical conductance method which uses the conductivity of the liquid film has been widely applied on measuring the liquid film thickness. Though the electrical method has an advantage in high spatial resolution, as the conductivity of liquid can be affected by its temperature variation, the conventional electrical conductance methods have a limitation in being applied on varying temperature conditions where a heat transfer is involved. The purpose of this study is to develop a three-ring liquid film sensor that overcomes the limitation of the conventional method. The three-ring conductance method can measure the film thickness regardless of temperature variation by compensating the change of liquid conductivity. Considering its application on a wide range of conditions such as high temperature or curved surfaces, the sensor was fabricated on flexible printed circuit board (FPCB) in this study. This paper presents the concept of the measurement method, design procedure, prototype sensor fabrication and calibration results.

• 대한물리의학회지
• /
• 제10권4호
• /
• pp.81-90
• /
• 2015

PURPOSE: The purpose of this study was to compare the muscle architecture of serratus anterior and lower trapezius using rehabilitative ultrasound imaging (RUSI) in affected and unaffected side of chronic stroke patients. METHODS: The participants were thirty five patients with stroke hemiplegia in this study. RUSI was used to measure the muscle thickness of the serratus anterior and lower trapezius muscles. We compared the muscle thickness according to affected side and sex, determined the reliability of the measurement image. Independent t-test, intra-class correlation coefficient (ICC) and standard error of measurement (SEM) were used for statistical analysis. RESULTS: Significant difference in muscle thickness of serratus anterior was observed between affected and unaffected side (p<.001). Muscle thickness according to gender showed a significant difference in unaffected side of serratus anterior (p<.05). Compare asymmetry ratio of serratus anterior and lower trapezius muscle thickness showed a significant difference (p<.001). ICC for intra-reliability was .944~.962 in serratus anterior and .873~.925 in lower trapezius muscle thickness, respectively. SEM was .001~.004 in serratus anterior and .002~.008 in lower trapezius muscle. CONCLUSION: This study, using RUSI, showed significant difference in muscle thickness of serratus anterior in affected and unaffected side of stroke patients. RUSI is a practical tool for measuring soft-tissue thickness in the scapular region muscle of stroke.

• 대한물리의학회지
• /
• 제8권2호
• /
• pp.231-238
• /
• 2013

PURPOSE: The purpose of this study is to find out the thickness variation of the superficial and deep abdominal muscles by measuring the thickness of the abdominal muscles. METHODS: 35 young, healthy adults(24 mens and 11 womens) participated in this study. The first, when only bridge exercise we had measured the thickness of their abdominal muscles by the ultrasound. The second, when the abdominal drawing-in during maintaining the bridge exercise we had measured the thickness of their abdominal muscles by the ultrasound. A pared t-test was used to determine a statistical significance for the thickness variation of the superficial and deep abdominal muscles. RESULTS: Results of before and after comparative analysis. The surperficial muscles(rectus abdominis, external obilique) statistically significantly reduced in the thickness and the deep muscle(transeverse abdominis) statistically significantly increased in the thickness. CONCLUSION: We have shown that the abdominal drawing-in exercise during maintaining the bridge exercise was effective to increase in strengthening abdominal deep muscle selectively.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2008년 영문 학술대회
• /
• pp.218-225
• /
• 2008

When the heat release and acoustic pressure fluctuations are generated in the combustor by irregular combustion, these fluctuations affect the mass flow rate of the propellants injected through the injectors. Also, the variations of the mass flow rate by these fluctuations again bring about irregular combustion and furthermore that is related with combustion instability. Therefore, it is very important to identify the mass variation for the pressure fluctuation on the injector and to investigate its transfer function. So, we first have studied quantifying the variation of mass flow rate generated in simplex swirl injector by injection pressure fluctuation. To acquire the transient mass flow rate in orifice with time, we have tried to measure of the flow axial velocity and liquid film thickness in orifice. The axial velocity is acquired through theoretical approach after measuring the pressure in orifice and the flow area in the orifice is measured by electric conductance method. As results, mass flow rate calculated by axial velocity and liquid film thickness measuring in orifice accorded with mass flow rate acquired by direct measuring method in the small error range within 1 percents in steady state and within 6 percents as average mass flow rate in pulsated state. Hence this method can be used to measure the mass flow rate not only in steady state but also in unsteady state because the mass flow rate in the orifice can acquire with time and this method shows very high accuracy based on the experimental results.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.25-30
• /
• 2004

The magnitude of constraint effect $A_{2}$ values were experimentally estimated using displacement according to measuring positions on the non-linear elastic plastic fracture toughness estimate. For 25.4 mm thickness SS400 steel CT specimen, constraint effect $A_{2}$ values we re dependent on specimen configuration and on measured displacement near crack front. Commonly, Estimating constraint effect $A_{2}$ measuring position for displacement should be existed inside plastic region. Therefore, the ${\delta}_{5}$ method was not reliable for evaluation of constraint effect $A_{2}$ values because measuring position for displacement is in elastic region at crack growth initiation in this paper.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.127.5-127
• /
• 2001

The 3-dimensional measuring machine by using an ultrasonic sensor is used one of the NDE (Nondestructive Evaluation). It is applied to the inspection of pipelines, boreholes, pressure vessel and tank, and so on. On particular when a harsh environment prohibits the use of moving mechanical parts. The 3-dimensional measuring machine by using an ultrasonic sensor, which measure 1-dimensional information and 2-dimensional information simultaneously from a target of inspection, and then re construct 3-dimensional information. So we can find the situation in progress and predict remaining life and corrosion without destructive examination. It´s a point of excellence that the 3-dimensional measuring machine is portable.