• Title, Summary, Keyword: PPF

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Comparison of the Characteristics of Cu-Sn and Ni Pre-Plated Frames Prepared by Electro-Plating (전기도금된 Cu-Sn과 Ni preplated frame의 특성 비교)

  • Lee, D.H.;Jang, T.S.;Hong, S.S.;Lee, J.W.;Yang, H.W.;Hahn, B.K.
    • Journal of the Korean institute of surface engineering
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    • v.39 no.6
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    • pp.276-281
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    • 2006
  • In order to improve the performance of PPFs (Pre-Plated Frames), a PPF that employed a Cu-Sn alloy instead of conventionally used Ni was developed and then its properties were investigated. It was found that the electoplated Cu-Sn alloy layer was a mixture of uniformly distributed fine crystallites, resulting In better wettability and crack resistance than those of Ni PPF. Moreover, as in Cu/Ni/Pd/Au PPF, migration of copper atoms from the base metal to the top of the Cu/Cu-Sn/Pd/Au PPF surface was not found although the Cu-Sn layer itself contained considerable amount of copper. It was expected that, by using the newly developed Cu-Sn PPF, any possible heat generation and signal interrupt caused by an external electro-magnetic field could be reduced because the Cu-Sn layer was paramagnetic, i.e., nonmagnetic.

Assessment of Palm Press Fibre and Sawdust-Based Substrate Formulas for Efficient Carpophore Production of Lentinus squarrosulus (Mont.) Singer

  • Osibe, Dandy Ahamefula;Chiejina, Nneka Virginia
    • Mycobiology
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    • v.43 no.4
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    • pp.467-474
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    • 2015
  • Development of efficient substrate formulas to improve yield and shorten production time is one of the prerequisites for commercial cultivation of edible mushrooms. In this study, fifteen substrate formulas consisting of varying ratios of palm press fibre (PPF), mahogany sawdust (MS), Gmelina sawdust, wheat bran (WB), and fixed proportions of 1% calcium carbonate ($CaCO_3$) and 1% sucrose were assessed for efficient Lentinus squarrosulus production. Proximate compositions of mushrooms produced on the different substrate formulas were also analysed and compared. Substrate formulations containing 85% PPF, 13% WB, 1% $CaCO_3$, and 1% sucrose were found to produce the highest carpophore yield, biological efficiency and size (206.5 g/kg, 61.96%, and 7.26 g, respectively). Days to production (first harvest) tended to increase with an increase in the amount of WB in the substrate formulas, except for PPF based formulas. The addition of WB in amounts equivalent to 8~18% in substrate formulas containing 80~90% PPF resulted in a decrease in the time to first harvest by an average of 17.7 days compared to 80~90% MS with similar treatment. Nutritional content of mushrooms was affected by the different substrate formulas. Protein content was high for mushrooms produced on formulas containing PPF as the basal substrate. Thus, formulas comprising PPF, WB, $CaCO_3$, and sucrose at 85% : 13% : 1% : 1%) respectively could be explored as starter basal ingredients for efficient large scale production of L. squarrosulus.

열린 박스 구조물에 대한 적응형 PPF 제어

  • 정환수;윤영동;신윤덕;기창두
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.109-109
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    • 2004
  • 구조물에 있어서 진동은 소음을 유발하며 구조물을 불안정하게 만드는 요인이 된다. 특히, 저주파 진동은 구조물에 미치는 영향이 크므로, 유연구조물의 저주파 진동모드들을 우선적으로 제어할 필요가 있다. 본 논문에서는 압전세라믹을 작동기로, 압전필름을 감지기로 사용하였고, 능동 제어 알고리즘의 하나인 적응형 디지털 PPF(Positive Position Feedback) 제어기를 구성하여 유연 외팔 평판과 열린 박스 구조물에서 저주파 진동을 감소시켰다.(중략)

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A Study on the Adaptive Roll Control Scheme for the Top Attack Smart Projectile (상부공격 지능탄의 회전각 적응제어 기법 연구)

  • 홍종태;정수경;최상경
    • Journal of the Korea Institute of Military Science and Technology
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    • v.3 no.2
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    • pp.61-70
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    • 2000
  • An Adaptive Positive Position Feedback method is presented for controlling the roll of the supersonic smart projectile. The proposed strategy combines the attractive attributes of Positive Position Feedback(PPF) of Goh and Caughey, and Lyapunov stability theorem. The parameters of Adaptive-PFF controller are adjusted in an adaptive mauler in order to follow the performance of an optimal reference model. In this way, optimal damping and zero steady-state errors can be achieved even in the presence of uncertain or changing plant parameters. The performance obtained with the Adaptive-PPF algorithm is compared with conventional PPF control algorithm. The results obtained emphasize the potential of Adaptive-PPF algorithm as an efficient means for controlling plants such as supersonic flight systems with uncertainties in real time.

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Development of the Active Vibration Absorber Using Piezoelectric Actuators (압전세라믹을 이용한 능동진동제어장치의 개발)

  • Kwak, Myung-Hoon;Heo, Seok;Kwak, Moon-K
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.476-481
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    • 2001
  • This research is concerned with development of the active vibration absorber using piezoelectric actuators. This active isolation system consists of a-pairs of PZT actuators bonded on a S-shaped aluminum plate and the passive damping material. The active system is connected to the passive system in series. In this paper, one of the popular control techniques which have been successfully applied to the smart structure is the Positive Position Feedback(PPF) control. The digital PPF control lows downloaded to the DSP chip and a main program, which runs SISO PPF algorithm. The structure and dynamic characteristics of the proposed active vibration isolation system and described in detail. To demonstate the effectiveness of the active vibration control, the PPF controller is first employed. Experimental results show that the active vibration isolation is possible by means of the proposed system.

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Vibration Control of Beam Containing ER Fluid Using PPF Control Scheme (PPF 제어기법을 적용한 전기점성유체가 함유된 보의 진동제어)

  • Yun Shin-Il;Chin Do-Hun;Yoon Moon-Chul
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.3
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    • pp.32-37
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    • 2005
  • Several types of smart materials and control scheme are available to adjust the structure actively in various external disturbances. A control scheme was introduced for a specific material. But the effectiveness of the control scheme has some limitation according to the choice of the smart materials and the response of the structure. The ER(Electrorheological) fluid is adequate for a large control force, and the PZT(lead zirconate titanate) patches are suitable for small but arbitrary control force at any point of the structure. It can be used for active control of structure by changing the dynamic characteristics of the structure. But it has some difficulty in suppressing the excited vibration in broad band. To compensate this resonance of the controlled structure, a hybrid controller was constructed using PPF(Positive position feedback) control with PZT and ER fluid control.

Analysis of Photosynthetic Photon Flux by Prototype of Rotational Lighting System for Plant Factory (식물공장을 위한 회전형 조명시스템 시제품의 광합성유효광양자속 분석)

  • Lee, Won-Sub;Kim, Sung-Gaun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.2
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    • pp.529-534
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    • 2013
  • Rotational lighting system for plant factory is the way to decrease high installation cost of the existing lighting system. A few of LEDs are used at the rotational lighting system in comparison with the existing lighting system to supply artificial lights to crops. At rotational lighting system, the manufacturing cost becomes very low by comparing with the existing lighting system. In this paper, the photosynthetic photon flux (PPF) is investigated in order that plants may grow. And PPF is analyzed with the rotational speed of blade and LED output by using the rotational lighting system prototype and quantum sensor. It is confirmed that constant PPF value of $200{\mu}mol{\cdot}m^{^-2}{\cdot}s^{^-1}$ is supplied with the blade rotation speed of 20rpm and LED output of IN 73%, CENTER 37% and OUT 50%. By comparing with the lighting system of existing plant factory, there is no difficulty to supply the light needed to grow plants by rotating a few of LEDs.

Variation of Photosynthetic Photon Flux in Commercial Plastic Greenhouses (상업용 플라스틱 온실의 광합성유효광량자속 변화)

  • Lee, Hyun-Woo;Kim, Young-Shik
    • Current Research on Agriculture and Life Sciences
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    • v.30 no.1
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    • pp.27-33
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    • 2012
  • This study was conducted to provide data necessary for clearing up the way to be able to improve covering and management method of covering material in commercial plastic greenhouse. The photosynthetic photon flux(PPF) in representative 4 different commercial tomato greenhouses was measured and analyzed. The variation trend of daily integral PPF was in agreement with that of the duration of sunshine. Each of daily integral PPF for 4 different experimental greenhouses was quite dissimilar, and was less than the amount of PPF necessary to grow tomato. October to November of beginning of winter was a good season to replace covering material in order to secure more PPF during insufficient winter season in greenhouse. The main inside factors to interrupt PPF incidence were thermal screen, inside covering material, condensation receiver in greenhouse. The single wide span greenhouse covered with PO film was superior to the other experimental greenhouses in the aspect of PPF transmittance.

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