An analytical and experimental investigation for an interstitial insulation technology

An insulation technique has been developed which contains a single or combination of materials to help minimize heat loss in actual industrial applications. For the petroleum industry, insulation for deep sea piping is one of the greatest challenges which would prevent the industry from meeting the high demand for oil through exploration into deeper ocean environments. At current seafloor depths (5,000~10,000ft), pipeline insulation is essential in preventing pipeline blockage resulting from the solidification of paraffin waxes and / or hydrate formation which exist in crude oil. To maintain crude oil temperatures above the paraffin solidification point (68°C or 155°F), new and better insulation techniques are essential to minimize pipeline heat loss and maintain crude oil temperatures. Therefore, the objective of this investigation was to determine whether or not the thermal resistance of a new insulation concept, which involves IIT (Interstitial Insulation Technology) with screen wire, was greater than existing readily available commercial products through analytical modeling and experimentation. The model takes into account both conforming and nonconforming interfaces at the wire screen contacts within the interstitial space between coaxial pipes. In addition, confirmation was needed to determine whether or not laboratory testing of simulated coupons translate to thermal performance for a prototype pipe segment that fabricated with two layers of low conductivity wire-screen (stainless steel) as the interstitial insulation material. Both the inner and outer surface temperatures of the coaxial pipes were measured in order to evaluate the effective thermal conductivity and thermal diffusivity of the insulation concept. The predicted results from the model compared very favorably with the experimental results, confirming both the trends and magnitudes of the experimental data. In other words, whether the reduction in heat transfer observed for small laboratory samples was realistic for application to a pipeline configuration. This effort involved both analytical modeling for all thermal resistances and experimental test runs for validation of the analytical model. Finally, it was a goal of this investigation to develop a simplified model for a multilayer composite structure which will include radiation heat transfer exchange among the layers that constitute the insulation. With the developed model, feasibility and performance characteristics of the insulation concept were predicted. The thermal predictions have demonstrated the thermal competitiveness of the interstitial insulation technology

Characteristics of vertical velocities estimated from drop size and fall velocity spectra of a Parsivel disdrometer

Vertical air velocities were estimated from drop size and fall velocity spectra observed by Parsivel disdrometers during intensive field observations from 13 June to 3 August 2016 around Mt. Jiri (1915ma.s.l.) in the southern Korean Peninsula. Rainfall and wind velocity data measured by Parsivel disdrometers and ultrasonic anemometers, respectively, were analyzed for an orographic rainfall event associated with a stationary front over Mt. Jiri on 1 July 2016. In this study, a new technique was developed to estimate vertical air velocities from drop size and fall velocity spectra measured by the Parsivel disdrometers and investigate characteristics of up-/downdrafts and related microphysics on the windward and leeward sides of the mountain. To validate results from this technique, vertical air velocities between the Parsivel disdrometers and anemometers were compared at different locations and were shown in quite good agreement with each other. It was shown that upward motion was relatively more dominant on the windward side and even during periods of heavy rainfall. In contrast, downward motion was more dominant on the leeward side during nearly the same periods of heavy rainfall. Occurrences of upward and downward motion were digitized as percentage values as they are divided by a total count of occurrences during the entire period. On the windward (leeward) side, the percentages of upward (downward) motion were much larger than those of downward (upward) motion. The mean rainfall intensity on the leeward side was stronger than on the windward side, suggesting that most of the rainfall on the leeward side was relatively more affected by the downward motion. With the estimated vertical air velocities, histogram characteristics of rainfall parameters were also examined between the windward and leeward sides

An analytical and experimental investigation for an interstitial insulation technology

An insulation technique has been developed which contains a single or combination of materials to help minimize heat loss in actual industrial applications. For the petroleum industry, insulation for deep sea piping is one of the greatest challenges which would prevent the industry from meeting the high demand for oil through exploration into deeper ocean environments. At current seafloor depths (5,000~10,000ft), pipeline insulation is essential in preventing pipeline blockage resulting from the solidification of paraffin waxes and / or hydrate formation which exist in crude oil. To maintain crude oil temperatures above the paraffin solidification point (68°C or 155°F), new and better insulation techniques are essential to minimize pipeline heat loss and maintain crude oil temperatures. Therefore, the objective of this investigation was to determine whether or not the thermal resistance of a new insulation concept, which involves IIT (Interstitial Insulation Technology) with screen wire, was greater than existing readily available commercial products through analytical modeling and experimentation. The model takes into account both conforming and nonconforming interfaces at the wire screen contacts within the interstitial space between coaxial pipes. In addition, confirmation was needed to determine whether or not laboratory testing of simulated coupons translate to thermal performance for a prototype pipe segment that fabricated with two layers of low conductivity wire-screen (stainless steel) as the interstitial insulation material. Both the inner and outer surface temperatures of the coaxial pipes were measured in order to evaluate the effective thermal conductivity and thermal diffusivity of the insulation concept. The predicted results from the model compared very favorably with the experimental results, confirming both the trends and magnitudes of the experimental data. In other words, whether the reduction in heat transfer observed for small laboratory samples was realistic for application to a pipeline configuration. This effort involved both analytical modeling for all thermal resistances and experimental test runs for validation of the analytical model. Finally, it was a goal of this investigation to develop a simplified model for a multilayer composite structure which will include radiation heat transfer exchange among the layers that constitute the insulation. With the developed model, feasibility and performance characteristics of the insulation concept were predicted. The thermal predictions have demonstrated the thermal competitiveness of the interstitial insulation technology

An Analysis of Social Participation Structure of Middle School Mathematics Classroom in Korea

2007The research aims to set the foundation for the understanding of the mathematics instruction in the institutional setting of a Korean middle school classroom. To fulfill this purpose, we focused on understanding the types and characteristics of participation structure created by class participants' interaction. One second grade middle school mathematics class was adopted for participant observation and long-term data was collected and analyzed. We have discovered several distinct types of social participation structure based on literature review and the criteria drawn from the comprehensive analysis of the characteristics of the teacher's and students' interaction and behavior

Trends in Mortality and Morbidity of Uterine Cervix, Female Breast, and Ovarian Cancer in Korea.

In Korea, leading causes of death have dramatically changed from infectious diseases to chronic degenerative illnesses, including malignant neoplasms since 1960. However, little is known about the long-term trends of female malignancies in Korea. This study was conducted to find epidemiological evidence of changes in mortality and morbidity of uterine cervix, female breast, and ovarian cancer through a long-term trends analysis with data representative of the Korean population. Age-standardized mortality rates of three female malignancies were markedly increasing throughout the observation period. Increment ratios in mortality were about two to five during the period 1981-1990. As a proxy estimate of incidence, age-standardized admission rates of female malignancies, as well as proportion index of admission due to each cancer to total admissions, showed a similar increasing trend from 1981 to 1990 in Korea. These results are highly suggestive of the view that both the mortality and morbidity for uterine cervix. female breast, and ovarian cancer must be increasing during the ten-year period since 1981 in Korea. Of the female malignancies, it is most likely that morbidity and mortality of uterine cervix cancer begin to decline after the end of the 19805 in Korea. Particularly noteworthy was a shift of the prevalent age for uterine cervix cancer to older women

Autonomous Control Strategy of DC Microgrid for Islanding mode using Power Line Communication

This paper proposes a DC-bus signaling (DBS) method for autonomous power management in a DC microgrid, used to improve its reliability. Centralized power management systems require communication between the power sources and loads. However, the DBS method operates based on the common DC-bus voltage and does not require communication. Based on the DC-bus voltage band, the DC-bus voltage can be used to inform the status of the DC-bus in various scenarios. The DC microgrid operates independently to maintain the system stably in the DC-bus voltage band. The DC microgrid can be divided into a grid-connected mode and an islanding mode. This paper proposes a control strategy based on power management of various independent components in islanding mode. In addition, the autonomous control method for switching the converter???s operation between grid-connected mode and islanding mode is proposed. A DC microgrid test bed consisting of a grid-connected AC/DC converter, a bidirectional DC/DC converter, a renewable energy simulator, DC home appliances and a DC-bus protector is used to test the proposed control strategy. The proposed autonomous control strategy is experimentally verified using the DC microgrid test bed

Comparison of total body irradiation-based or non-total body irradiation-based conditioning regimens for allogeneic stem cell transplantation in pediatric leukemia patients

Purpose : This study aims to compare the outcome of total body irradiation (TBI)- or non-TBI-containing conditioning regimens for leukemia in children. Methods : We retrospectively evaluated 77 children conditioned with TBI (n=40) or non-TBI (n=37) regimens, transplanted at Chonnam National University Hospital between January 1996 and December 2007. The type of transplantation, disease status at the time of transplant, conditioning regimen, engraftment kinetics, development of graft-versus-host disease (GVHD), complications, cause of deaths, overall survival (OS), and event-free survival (EFS) were compared between the 2 groups. Results : Among 34 patients with acute lymphoblastic leukemia (ALL), 28 (82.4%) were in the TBI group, while 72.7% (24/33) of patients with myeloid leukemia were in the non-TBI group. Although the 5-year EFS of the 2 groups was similar for all patients (62% vs 63%), the TBI group showed a better 5-year EFS than the non-TBI group when only ALL patients were analyzed (65% vs 17%&#59; P =0.005). In acute myelogenous leukemia patients, the non-TBI group had better survival tendency (73% vs 38%&#59; P=0.089). The incidence of GVHD, engraftment, survival, cause of death, and late complications was not different between the 2 groups. Conclusion : The TBI and non-TBI groups showed comparable results, but the TBI group showed a significantly higher 5-year EFS than the non-TBI group in ALL patients. Further prospective, randomized controlled studies involving larger number of patients are needed to assess the late-onset complications and to compare the socioeconomic quality of life

Resonant two-photon ionization and laser induced fluorescence spectroscopy of jet-cooled adenine

Resonant two-photon ionization (R2PI) and laser induced fluorescence (LIF) techniques were used to obtain the electronic spectra of the jet-cooled DNA base adenine. The spectrum consisted of two bands of the n??* and ????* characters. The vibronic mixing between the two states resulted in the broad absorption whose onset was located 1100 cm -1 above the n??* origin. The presence of these electronically states revealed the presence of vibronic mixing.open12813