• Title/Summary/Keyword: Machine-to-machine (M2M)

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A Study on Current Waveform Control and Performance Improvement for Inverter Arc Welding Machine (인버터 아크 용접기의 파형제어기법 및 성능향상에 관한 연구)

  • 채영민;고재석;김진욱;이승요;최해룡;최규하
    • The Transactions of the Korean Institute of Power Electronics
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    • v.4 no.2
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    • pp.128-137
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    • 1999
  • Recently the pelionnance of CO2 arc welding machine has been advanced significantly through the adoption of i invelter circuit topology. which made it possible to improve welding perfonnances such as spatter generation and bead s state. But the conventional inverter arc welding machine generates constant output voltage which cause much spatter g generation dUling short-circuit and arc start time because it is unable to control output current instantaneously. So this p paper representes wavefCnm controlled inverter arc welding machine which control the wavefonn of welding current and t thus to suppress the spatter generation. And the system designed in this paper is the digital controller using single chip m microprocessor of 80C196KC. As a result of perfonnance test for this system, the spatter generation is reduced and s shOlt-circuit time period is stabilized compared to conventional one. And more by using switched mode rectifier for A AC/DC power convelter. unity power factor is maintained and low order halmonic spectrum is supressed.

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Performance Evaluation of the Screw-Type Oil Expeller for Extracting Mee (Madhuca longifolia) Oil

  • Bandara, D.M.S.P.;Dissanayake, C.A.K.;Dissanayake, T.M.R.;Rathanayake, H.M.A.P.;Senanayake, D.P.
    • Journal of Biosystems Engineering
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    • v.41 no.3
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    • pp.177-183
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    • 2016
  • Purpose: Mee (Madhuca longifolia) is an economically important tree growing throughout Sri Lanka. Its importance is mainly attributed to its oil with high nutritional and medicinal values. However, an inefficient extraction method limits its use. This study revealed the possibility of extracting oil from mee seeds by using a screw-type oil expeller. Methods: A popular screw-type oil expeller was used in the experiment. Extract bar clearance and speeds of the main spiral shaft were altered to increase the oil expelling efficiency of the machine. The quality of refined oil at the optimum oil yield was determined by measuring the refractive index, saponification value, iodine value, unsaponifiable matter, free fatty acid, and specific gravity. Results: An optimum yield of 35% oil was obtained when the machine capacity was 30 kg/h and energy consumption was 0.13 kWh/kg. This optimum machine condition was observed at an extract bar clearance of 0.5 mm and a main spiral shaft speed of 90 rpm. The refractive index, saponification value, iodine value, unsaponifiable matter, free fatty acid, and specific gravity of the oil were 1.4, 203, 59, 3.5%, 0.2%, and 0.907 g/cm3 respectively. Color of the mee oil was closer to yellow, which is revealed by the lightness value (L) of 24.93 and positive value (b) of 11.81. Conclusion: The screw-type oil expeller can be used for economically extracting mee oil on a commercial scale.

A Study of Evaluation for Optimum Content and Bond Strength Properties of Bituminous Materials applied for preventing Separation of Asphalt Pavement Layers (아스팔트 포장층 분리억제용 역청재료의 부착성능 및 최적함량 평가에 대한 연구)

  • Kim, Dowan;Lee, Sangyum;Mun, Sungho
    • International Journal of Highway Engineering
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    • v.18 no.6
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    • pp.137-143
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    • 2016
  • OBJECTIVES : Bituminous materials, such as tack coat, are utilized between pavement layers for improving the bond strength in pavement construction sites. The standards regarding the application of bituminous material are not clearly presented in the Korean construction guideline without RS(C)-4. Hence, the objective of this study is to determine the optimum content of bituminous materials by analyzing interlayer shear strength (ISS) from the direct shear tester, which was developed in this research. The shear strength of tack coat was defined with the sort of bituminous materials. METHODS : The mixtures for the shear test were made using marshall mix design. The specimens were vertically and horizontally separated for the direct shear test. The separated specimens were bonded using bituminous material. The objectives of the experiment are to determine the performance of bond and shear properties resulting from slippage, rutting, shovel, and corrugation of asphalt pavements. A machine based on the Louisiana interlayer shear strength tester (LISST) of NCHRP Report-712 was developed to determine the ISS. The applied types of tack coat were RS(C)-4, AP-3, QRS-4, and BD-coat with contents of $0.3{\ell}/m^2$, $0.45{\ell}/m^2$, $0.6{\ell}/m^2$, and $0.8{\ell}/m^2$, respectively. RESULTS : Table 2 gives the results of the direct shear test using the developed shear machine. The BD-coat type indicated the highest average ISS value compared to the others. Between the surface and binder course, optimum tack coat application rates for AP-3, RS(C)-4, QRS-4, and BD-Coat were $0.6{\ell}/m^2$, $0.3{\ell}/m^2$, $0.6{\ell}/m^2$, and $0.45{\ell}/m^2$, respectively. These optimum contents were determined using the ISS value. CONCLUSIONS : The ISS values of AP-3, RS(C)-4, and QRS-4 showed similar tendencies when ISS increased in the range $0.3{\sim}0.6{\ell}/m^2$, while ISS decreased when the applied rate exceeded $0.6{\ell}/m^2$. Similarly, the highest ISS value of the BD-coat was observed when the applied rate was $0.45{\ell}/m^2$. However, shear strength was similar to the maximum value of ISS when the tack-coat application rate of BD-Coat exceeded $0.45{\ell}/m^2$.

Estimation of Cattle Wastewater Treatment using Singang Advance Biology Reactor (SAB) (SAB 고율미생물반응기를 이용한 축산폐수처리의 성능 평가)

  • Lim, Bongsu;Kim, Doyoung;Park, Sungsoon
    • Journal of Korean Society on Water Environment
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    • v.25 no.5
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    • pp.727-734
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    • 2009
  • This study was carried out to evaluate the high rate biological reactor such as lab scale reactor before the application in site, and to get the basic data for possibility using liquid fertilizer with the effluent from biological reactor when the centrifugal machine was applied. The total volume of this reactor in 6 L, in composted of anoxic reactor (2 L), aerobic reactor (2 L), and nitification reactor (2 L). BOD removal efficiency rates when centrifugal machine was applied after effluent from biological reactor are over than 95%. This biological reactor was required post process to satisfy the effluent standards, and was need centrifugal machine to control the washout of microbes in the reactor. T-N removal efficiency rate in HRT 24 hr with centrifugation is 80.0%, and it is desirable to operate less than $1.3kgN/m^3{\cdot}d$ for 70% of T-N removal efficiency rate. T-P removal efficiency rate in HRT 24 hr is 68.2%, and become higher 71.3% after centrifugation. Considering in the 28.6% T-N removal efficiency rate, the nitrogen contents of the effluent from reactor is 0.34% to satisfy the liquid fertilizer.

Analysis of the Optimized Sewing Speed for the Sewing Operation Standardization in the Garment Manufactures (의류 제품의 봉제작업 표준화를 위한 최적 봉제시간 연구)

  • 김선희
    • Journal of the Korean Society of Costume
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    • v.53 no.7
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    • pp.139-146
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    • 2003
  • This study was aimed at analyzing a characteristics of the sewing machines and analyzing the effective sewing time in the garment manufacture process, therefore to obtain the basic data concerned with the sewing. operation standardization. The two methods were experimented. First, two garment factories established in Seoul and Geonggi province were randomly selected for the analyzing the sewing speed of the sewing operator for the optimized sewing speed using the equipment of Digital Tachometer HT4100. Second, five garment factories established in Seoul and Geonggi province were randomly selected to analyze the required time data to reach the fixed sewing speed using the lock stitch sewing machine which was used in the sewing factories. The results are divided into 3 categories as follows; 1) Survey results for the optimized sewing speed : The sewing operations of 10~20 cm range were most frequently selected in seam constructions in Korean sewing factories, and the sewing speed of 2,500 R.P.M was most used; 2) Required time to reach the fixed sewing speed using the lock stitch sewing machine : The mean of required time to the fixed sewing speed of 2.500 R.P.M was 3.5 second, and the mean of the real-sewing length during the 3.5 second was 43.8 cm ; 3) Analysis of the optimized sewing speed calculated using these results : The optimized sewing speed for the sewing manufacturers of the upward of 43.8 cm was 2,500 R.P.M. and for the sewing manufacturers of the below of 42.2 cm, the optimized sewing speed was 2.450 R.P.M.

A Study on Measurement System Accuracy of Theodolite System(IV) - A Measurement System Accuracy depending on a Distance of Scale Bar on the Distance 4m between two Theodolites (데오드라이트 시스템의 측정 정확도에 대한 연구(IV) - 시준거리 4m에서의 기준자 거리에 따른 측정 정도)

  • Yoon Yong-Sik;Lee Dong-Ju;Park Yo-Chang
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.3
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    • pp.67-73
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    • 2005
  • An accuracy of theodolite system may be affected by a measurement environment and a measurement distance change from theodolite to scale bar and/or targets. This study was performed for measuring an accuracy when the distance from thodolite system to scale bar was changed $2\~6m$ on the distance 4m between two theodolites. The results showed that an accuracy was ${\pm}0.025mm$ or better when the distance from theodolite system to targets was 3, 4 and 5m. According to the results, it was found that the best distance from theodolite system to scale bar was $3\~4m$ when the collimation distance was $3\~4m$.

Application of GIS for Selection of Logging Operation Machine (벌출작업 기종의 선정을 위한 GIS 활용)

  • Jeon, Kwon-Seok;Ma, Ho-Seop
    • Journal of the Korean Association of Geographic Information Studies
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    • v.6 no.1
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    • pp.85-97
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    • 2003
  • This study was aimed at suggest a proper logging method of mountain forest using geographic information system(GIS) based on digital terrain model(DTM) in the National Forest at Mt. Kumsan in Namhae-gun, Gyungsangnam-do, which has about 2,948 ha in area. The areal percentage of 201 to 250m in the elevation was about 15.5%, elevation of 251 to 300m was 14.5%, and 78.75% for higher than 400m. The accumulated areal percentage of below 30% in the gradient was 17.2%, and 81.0% for steeper than 60%. The area for tractor skidding was 17.2%(511.7ha), the area for tractor attached winch skidding was 63.8%(1,896.3ha) and 18.4%(545.5ha) for cable yarding. It is important to choose the proper logging machines for timber harvesting. In general, the selection of logging operation system was affected several major environmental factors like as terrain conditions(slope gradient, slope length) and stand factors. The rate of middle slope gradients in terrain conditions showed higher than that of steep slope gradients in this area. Therefore, it considered that the logging operation system in this area could apply to tractor+winch operating machine according to terrain conditions.

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Study on the measurement of bolt axial force by ultrasonic wave (초음파에 의한 볼트의 축력측정)

  • 한응교;김재열
    • Journal of the korean Society of Automotive Engineers
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    • v.10 no.3
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    • pp.38-44
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    • 1988
  • It is important to control the axial forces of high tension bolts such as the automobile, construction machine, aircraft, marine engine bolts. However, the direct method to measure the axial forces of bolts practically have not been found out. The ultrasonic techniques is based on the principles that the bolt tensile elongation and ultrasonic velocity changes are proportional to the axial force below the yield point of the materials. From the result of the experiment, the coefficient of acoustoelasticity k could be measured as - 11.18*10$_{-5}$m $m^{2}$k $g_{f}$./.

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A Study on Measurement Accuracy of Theodolite System(III) - A Measurement System Accuracy depending on a Distance of Scale Bar on the Distance 3 m between two Theodolites (데오드라이트 시스템의 측정 정확도에 대한 연구(III) - 시준거리 3 m에서 기준자 거리에 따른 측정 정도)

  • Yoon Yong Sik;Lee Dong Ju;Yoon In Jin
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.2
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    • pp.48-54
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    • 2005
  • The theodolite system consists of two theodolites, a scale bar and a target bu. A measurement accuracy of theodolite system is affected by a measurement distance of each equipment. This study was performed fir measuring an accuracy when the distance from theodolite to scale bar was changed 2~ 6 m on two theodolites distance 3 a The results showed thai the measurement accuracy could be $\pm$0.021 mm when the distance from theodolite to target was 2,3 and 6 n Specially, it was found that the maximum measurement accuracy was 10.017mm on theodolite collimation distance 3m and the distance 4 m of the theodolite and scale bar.

Pressure Drop and Refrigerant-Entrainment Characteristics of the Eliminators used in Absorption Chillers (흡수식 냉동기용 엘리미네이터의 압력손실 및 액적유입 특성)

  • 정시영;류진상;이상수;이정주
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.2
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    • pp.109-115
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    • 2003
  • The performance of two vertical-blade eliminators (V1, V2) and two horizontal-blade ones (H1, H2) for absorption chillers were tested in terms of pressure drop and refrigerant entrainment. The test was carried out using a wind tunnel with a cross section of 300 mm$\times$300 mm. The pressure drop of four eliminators tested was found to be in the rage of 1.0~2.7mm $H_2O$ at the face velocity of 2m/s. In the refrigerant entrainment test the vertical-blade eliminators showed much better performance than the horizontal-blade ones. The horizontal-blade eliminators showed satisfactory results at the air velocity of 2m/s but exceeded the limit value at 3 m/s. Since the cooling capacity of a machine is lowered by about 2.5% at the pressure drop of 1 m $H_2O$, more researches are required to reduce the pressure drop in the eliminator.