• Title/Summary/Keyword: In-situ measurement

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In-Situ Diagnosis of Vapor-Compressed Chiller Performance for Energy Saving

  • Shin Younggy;Kim Youngil;Moon Guee-Won;Choi Seok-Weon
    • Journal of Mechanical Science and Technology
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    • v.19 no.8
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    • pp.1670-1681
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    • 2005
  • In-situ diagnosis of chiller performance is an essential step for energy saving business. The main purpose of the in-situ diagnosis is to predict the performance of a target chiller. Many models based on thermodynamics have been proposed for the purpose. However, they have to be modified from chiller to chiller and require profound knowledge of thermodynamics and heat transfer. This study focuses on developing an easy-to-use diagnostic technique that is based on adaptive neuro-fuzzy inference system (ANFIS). The effect of sample data distribution on training the ANFIS is investigated. It is found that the data sampling over 10 days during summer results in a reliable ANFIS whose performance prediction error is within measurement errors. The reliable ANFIS makes it possible to prepare an energy audit and suggest an energy saving plan based on the diagnosed chilled water supply system.

The Effect of Deposition Rate on In-Situ Intrinsic Stress Behavior in Cu and Ag Thin Films (증착 속도 변화에 따른 구리와 은 박막의 실시간 고유응력 거동)

  • Ryu, Sang;Lee, Kyungchun;Ki, Youngman
    • Korean Journal of Metals and Materials
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    • v.46 no.5
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    • pp.283-288
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    • 2008
  • We observed the in-situ stress behavior of Cu and Ag thin films during deposition using a thermal evaporation method. Multi-beam curvature measurement system was used to monitor the evolution of in-situ stress in Cu and Ag thin films on 100 Si(100) substrates. The measured curvature was converted to film stress using Stoney formula. To investigate the effects of the deposition rates on the stress evolution in Cu and Ag thin films, Cu and Ag films were deposited at rates ranging from 0.1 to $3.0{\AA}/s$ for Cu and from 0.5 to $4.0{\AA}/s$ for Ag. Both Cu and Ag films showed a unique three stress stages, such as 'initial compressive', 'a tensile maximum' and followed by 'incremental compressive' stress. For both Cu and Ag films, there is no remarkable effect of deposition rate on the thickness and average stress at the tensile maximum. There is, however, a definite decrease in the incremental compressive stress with increasing deposition rate.

The Effect of Substrate Surface Roughness on In-Situ Intrinsic Stress Behavior in Cu Thin Films (기판 표면 조도에 따른 구리박막의 실시간 고유응력 거동)

  • Cho, Moohyun;Hwang, Seulgi;Ryu, Sang;Kim, Youngman
    • Korean Journal of Metals and Materials
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    • v.47 no.8
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    • pp.466-473
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    • 2009
  • Our group previously observed the intrinsic stress evolution of Cu thin films during deposition by changing the deposition rate. Intrinsic stress of Cu thin films, which show Volmer-Weber growth, is reported to display three unique stress stages, initial compressive, broad tensile, and incremental compressive stress. The mechanisms of the initial compressive stress and incremental compressive stages remain subjects of debate, despite intensive research inquiries. The tensile stress stage may be related to volume contraction through grain growth and coalescence to reduce over-accumulate Cu adatoms on the film surface. The in-situ intrinsic stresses behavior in Cu thin films was investigated in the present study using a multi-beam curvature measurement system attached to a thermal evaporation device. The effect of substrate surface roughness was monitored by observed the in-situ intrinsic stress behavior in Cu thin films during deposition, using $100{\mu}m$ thick Si(111) wafer substrates with three different levels of surface roughness.

Effect of annealing of Pb(La,Ti)$O_3$ thin films by Pulsed laser deposition process (펄스 레이저 증착법으로 제작된 PLT박막의 열처리 효과 연구)

  • Hur, Chang-Hoi;Shim, Kyung-Suk;Lee, Sang-Yeol
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1483-1484
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    • 2000
  • Dielectric thin films of PLT(Pb(La.Ti)O3) for the application of highly integrated memory devices have been deposited on Pt/Ti/SiO2/Si substrates in situ by pulsed laser deposition(PLD). We have systematically investigated the variation of grain sizes depending on the condition of post-annealing and the variation of deposition rate. Both in-situ annealing and ex-situ annealing have been compared depending on the annealing time. C-V measurement, ferroelectric properties, leakage current and SEM were performed to investigate the electrical properties and the microstructural properties of Pb(La,Ti)$O_3$ films.

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In-Situ Measurement of Chiller Performance and Thermal Storage Density of an Ice Thermal Storage System (빙축열 시스템 냉동기 성능 및 축열밀도 현장측정 기법연구)

  • Shin Younggy;Yang Hooncheul;Tae Choon-Seob;Cho Soo;Kim Youngil
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.12
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    • pp.1204-1209
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    • 2005
  • In-situ measurement was made to evaluate chiller performance and thermal storage density of an ice thermal storage system. The system belonged to a big hotel and the measurement was conducted during late October. Owing to very small cooling load, the data logging was possible for a single thermal storage cycle. However, operation history of the chiller showed a relatively good spectrum of data for performance evaluation. COP and thermal storage density were calculated. The COP at full load was about 4.07, which was lower than $4.8\~6.4$ of new chillers. The measured storage density was about $10.9RT-h/m^3\;(=152MJ/m^3)$, which also was lower than a criterion of normal performance $(above\;13.0RT-h/m^3\;or\;181MJ/m^3)$. The study result provides technical basis for quantitative ESCO business scenario.

Carbonation depth prediction of concrete bridges based on long short-term memory

  • Youn Sang Cho;Man Sung Kang;Hyun Jun Jung;Yun-Kyu An
    • Smart Structures and Systems
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    • v.33 no.5
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    • pp.325-332
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    • 2024
  • This study proposes a novel long short-term memory (LSTM)-based approach for predicting carbonation depth, with the aim of enhancing the durability evaluation of concrete structures. Conventional carbonation depth prediction relies on statistical methodologies using carbonation influencing factors and in-situ carbonation depth data. However, applying in-situ data for predictive modeling faces challenges due to the lack of time-series data. To address this limitation, an LSTM-based carbonation depth prediction technique is proposed. First, training data are generated through random sampling from the distribution of carbonation velocity coefficients, which are calculated from in-situ carbonation depth data. Subsequently, a Bayesian theorem is applied to tailor the training data for each target bridge, which are depending on surrounding environmental conditions. Ultimately, the LSTM model predicts the time-dependent carbonation depth data for the target bridge. To examine the feasibility of this technique, a carbonation depth dataset from 3,960 in-situ bridges was used for training, and untrained time-series data from the Miho River bridge in the Republic of Korea were used for experimental validation. The results of the experimental validation demonstrate a significant reduction in prediction error from 8.19% to 1.75% compared with the conventional statistical method. Furthermore, the LSTM prediction result can be enhanced by sequentially updating the LSTM model using actual time-series measurement data.

Target strength characteristics of sailfin sandfish (Arctoscopus japonicus) using ex situ experiment and acoustic model (음향 실험 및 모델 기법을 이용한 도루묵 (Arctoscopus japonicus)의 음향산란반사강도 특성)

  • LEE, Hyungbeen;LEE, Kyounghoon;YOON, Eun-A;HWANG, Kangseok;CHOI, Junghwa;PARK, Tae-Geon
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.51 no.3
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    • pp.405-413
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    • 2015
  • Acoustic target strength (TS) measurement and theoretical acoustic scattering models were applied to estimate the TS for assessing the fish biomass. TS measurement was made of ex situ sailfin sandfish Arctoscopus japonicus at 70 and 120 kHz, and then compared to backscatter model prediction. The live sandfish was tethered in seawater using monofilament lines. Measurements were made versus incidence angle, $-50^{\circ}$ to $50^{\circ}$ relative to dorsal aspect directions. Distorted wave Born approximation (DWBA) model was used to calculated TS pattern. The TS values of sandfish (body length: 16.2 cm) at 70 and 120 kHz were -66.94 dB and -64.45 dB, respectively, and were about 20 dB lower than TS of other fishes in Korea waters. These TS levels were distributed within the range of the theoretical TS. Ex situ measurement and theoretical TS may be applied to improve acoustical detection and biomass estimation of the sandfish, and is necessary to measure with various lengths.

In situ side-aspect target strength of Japanese anchovy (Engraulis japonicus) in northwestern Pacific Ocean (북서 태평양 멸치(Japanese anchovy)에 대한 측면 음향 반사강도 특성)

  • Lee, Hyung-Been;Kang, Don-Hyug
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.46 no.3
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    • pp.248-256
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    • 2010
  • Acoustic side-aspect target strength (TS) of living Japanese anchovy (Engraulis japonicus) was measured at 120kHz during in situ experiments. The data were collected by lowering and horizontally projecting the splitbeam transducer into the anchovy school. For analysis and interpretation of the side-aspect TS data, acoustic theoretical model, based on the fish morphology, and dorsal-aspect TS data were used. Total length of the anchovy ranged from 6.6 to 12.8cm (mean length 9.3cm). The side-aspect TS distributed between -40 and -55dB, has an obvious length dependency. The mean side-aspect TS of the anchovy was -47.8dB, and the TS was about 2dB higher than mean TS generated from dorsal-aspect measurements. With reference to maximum TS, the results of the side-aspect TS were distributed within the range of the theoretical and dorsal-aspect TS. Apparently these tendency indicates that side-aspect TS measured from the study is useful data. These in situ measurements of side-aspect TS can be applied to improve acoustic detection and estimates of the anchovy, and is necessary to measure with a various frequency and length for making enhance data.

Non-invasive Methods for Determination of Cellular Growth in Podophyllum hexandrum Suspension Cultures

  • Chattopadhyay, Saurabh;Bisaria, V.S.;Scheper, T.;Srivastava, A.K.
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.7 no.6
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    • pp.331-334
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    • 2002
  • Culture conductivity and on-line NADH fluorescence were used to measure cellular growth in plant cell suspension cultures of Podophyllum hexandrum. An inverse correlation between dry cell weight and medium conductivity was observed during shake flask cultivation. A linear relationship between dry cell weight and culture NADH fluorescence was obtained during the exponential phase of batch cultivation In a bioreactor under the pH stat (pH 6) conditions. It was observed that conductivity measurement were suitable for biomass characterisation under highly dynamic uncontrolled shake flask cultivation conditions. However, if the acid/alkali feeding is done for pH control the conductivity measurement could not be applied. On the other hand the NADH fluorescence measurement allowed online-in situ biomass monitoring of rather heterogenous plant cell suspension cultures in bioreactor even under the most desirable pH stat conditions.

The Characteristics of Internal Waves Observed by SAR and in-situ Measurement Data Near Ocheong-Do in the Yellow Sea (SAR와 현장관측에 의한 황해 어청도 주변 해역에서의 내부파 특성)

  • 김태림;최현용
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.8 no.2
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    • pp.132-137
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    • 2003
  • Observations of internal waves in the southwest coastal waters of Korea have been made using a mooring measurement and satellite SAR together. From May 28 to May 30 in 2002, thermistor chains with RCM and ADCP mooring measurements were carried out at 10 kin west of Ocheong-Do, together with a CTD field sur-vey on the surrounding waters. Also, a SAR image was acquired on May 29 at 06:53. The data from the in-situ measurement show several internal wave packets passing through the mooring point and the SAR image reveals numbers of internal wave packets distributed around the point. Temporal and spatial characteristics of internal waves in the southwest coastal waters were analyzed using the data from mooring measurement, SAR image, and the K-dv equation. The internal waves are important phenomena in terms of physical oceanography and military as well as marine biology. They should be considered as one of important features in the southwest coastal waters in summer.