Efficient Data Integration and Database Design for Aerospace Design Frameworks

Tun Lwin,Thawdar Lwin,Su Su Aung,Jae-Woo Lee,Sangho Kim 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.4

The data integration processes of heterogeneous legacy systems are key aspect of developing in computerized systems and integration of design frameworks. In this research, the aerospace design framework with legacy programs is implemented and data integration wrapper program is mapped between different data resources from legacy programs. Thus, the database table connector (DTC) wrapper program is created and interacted between database management system and legacy codes. The DTC provides data integration among different data resources and data management by using SQL querying. The DTC enables designers or developers to provide rapid and efficient development of different data resources integration in design frameworks. By using DTC and database design, small-sized fixed wing aircraft framework and helicopter rotor blade framework are implemented.

Oxide formation mechanism and its effect on the microstructure and thermoelectric properties of <i>p-type</i> Bi_0.5Sb_1.5Te₃ alloys

Lwin, May Likha,Dharmaiah, Peyala,Madavali, Babu,Lee, Chul-Hee,Shin, Dong-won,Song, Gian,Lee, Kap-Ho,Hong, Soon-Jik Elsevier 2018 Intermetallics Vol.103 No.-

<P><B>Abstract</B></P> <P>Bismuth antimony telluride based thermoelectric (TE) materials have been intensively developed and synthesized using different mechanisms, for the room temperature TE applications. In particular, bismuth antimony telluride based TE alloys are very sensitive to deviations in their composition, and to contamination during the materials synthesis. Oxygen contamination during Bi-Sb-Te based materials synthesis is one of the critical factors that alters or diminishes thermoelectric-transport properties. Thus, in this study, how the oxide formation mechanism on the powder surface and bulks of p-type Bi<SUB>0.5</SUB>Sb<SUB>1.5</SUB>Te<SUB>3</SUB> alloys affected the microstructural features and thermoelectric properties were elucidated quantitatively. While applying heat treatment (HT) to Bi<SUB>0.5</SUB>Sb<SUB>1.5</SUB>Te<SUB>3</SUB> powder, the constituent elements interacted with the ambient atmosphere and formed a new oxide phase which acted as a barrier to carrier transport. At the initial stage (300 °C) of heat treatment, only the powder surface was oxidized due to the reaction of outer surface atoms with atmospheric air and moisture. While increasing in temperature during HT, this surface oxygen contamination diffused further inside the powder through the grain boundaries. More diffusion and spreading occurred throughout the matrix at 450 °C. The increment of oxygen content from 0.05 to 0.82 wt% drastically decreased the electrical conductivity by 67%, and thermal conductivity by 7% at the heat treatment temperature of 450 °C. This reduction behavior is mainly due to severe scattering of the carriers/phonons at the new formation of oxide (Sb<SUB>2</SUB>O<SUB>3</SUB>) phase near grain boundaries and within the matrix. At a glance, a small increase in the oxygen content wouldn't significantly influence the thermoelectric properties; however, at a certain level of oxide formation (0.82 wt%), severe effects could occur due to the intensified scattering or trapping of carriers by the oxide barrier formation at the grain boundaries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Determined the oxygen concentration of different heat-treated GA powder and SPS bulks. </LI> <LI> Elucidation the relation between the mechanism of oxide formation and the thermoelectric properties of Bi<SUB>0.5</SUB>Sb<SUB>1.5</SUB>Te<SUB>3</SUB> alloys. </LI> <LI> Identified Sb<SUB>2</SUB>O<SUB>3</SUB> phase at the grain boundary and within the grains. </LI> <LI> Demonstrated the thermoelectric performance in Bi<SUB>0.5</SUB>Sb<SUB>1.5</SUB>Te<SUB>3</SUB> alloys with oxygen content. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

PD Diagnosis on 22.9kV XLPE Underground Cable using Ultra-wideband Sensor

Lwin, Kyaw-Soe,Lim, Kwang-Jin,Park, Noh-Joon,Park, Dae-Hee The Korean Institute of Electrical Engineers 2008 Journal of Electrical Engineering & Technology Vol.3 No.3

This paper presents compact low frequency ultra-wide band (UWB) sensor design and study of the partial discharge diagnosis by sensing electromagnetic pulse emitted from the partial discharge source with the newly designed UWB sensor. In this study, we designed a new type of compact low frequency UWB sensor based on microstrip antenna technology to detect both the low frequency and high frequency band of the partial discharge signal. Experiments of offline PD testing on medium voltage (22.9kV) underground cable mention the comparative results with the traditional HFCT as a reference sensor in the laboratory. In the series of comparative tests, the calibration signal injection test provided with the conventional IEC 60270 method and high voltage injection testing are included.

Development of Airworthiness Database System with Validation Process for Design Programs of General Aviation Aircraft

Lwin, Tun,Lee, Jae Woo,Kim, Sangho,Lee, Hyojin The Korean Society for Aeronautical and Space Scie 2012 International Journal of Aeronautical and Space Sc Vol.13 No.4

In this paper, a design process is established by integrating aviation safety requirements for the development of general aviation aircraft. An Airworthiness-Design Integration System, which integrates certification requirements with the entire design/analysis process, is developed and presented. For the proposed system, KAS 23/FAR 23/AC 23/CS 23 certification regulations are analyzed to determine design constraints and system compliance checks and to construct an ER&G (Engineering Requirement and Guide) and a Design-Certification Related Table (DCRT). Furthermore, through building a DB (Data Base), the management of design and certification related resources for developing a FAR 23 class aircraft are made. Certification tools and resources are also efficiently managed by the DB. The connection between the certification requirements and the detailed design process is proposed in this system. Tracking of this proposed method is validated by configuring a USE CASE and a system. The Airworthiness-Design Integration system will be constructed based on the system's design plan, certification system, and usage scenarios.

ASEAN Free Trade Area and late Comers : The Case of Vietnam

Lwin, Maung Maung 大田大學校 社會科學硏究所 2002 社會科學論文集 Vol.21 No.2

Differential effects of postharvest 1-MCP treatment on fruit quality and targeted major metabolites in long-term cold-stored ‘Wonhwang’ pears

Lwin Hnin Phyu,이진욱 한국원예학회 2022 Horticulture, Environment, and Biotechnology Vol.63 No.4

‘Wonhwang’ Asian pears could be intolerant to the incidence of physiological disorders during long-term storage. 1-Methylcyclopropene (1-MCP) technology is commonly used in the fruit industry to retain fruit quality during cold storage and the handling period. Thus, the objectives of this study were to evaluate the effectiveness of postharvest 1-MCP treatment on fruit physiological characteristics, physiological disorders, and the major metabolic responses of organic acids, soluble carbohydrates, and free amino acids in long-term cold-stored ‘Wonhwang’ pears. The 1-MCP treatment reduced flesh firmness but increased weight loss during storage. It also reduced the content of fructose, glucose, and malic acid but retained higher levels of sucrose and sorbitol during the second half of storage compared to the untreated control. The 1-MCP application enhanced the severity and incidence of cavities and water soaking during cold storage and increased methionine levels in cold-stored pears. The scores plot of principal component analysis indicated that 1-MCP treatment caused the response variables to diverge during the second half of storage. Additionally, the correlation coefficient network indicated that 1-MCP treatment differentially mediated the correlation coefficients of fruit quality parameters and targeted metabolites in long-term cold-stored pears. These results suggest that postharvest 1-MCP application affects the differential responses of fruit quality parameters in Asian pears stored at 0.5 °C for up to 6 months.

Differential responses of bulb quality attributes, mineral nutrient contents, and targeted major metabolites in onion bulbs after long-term commercial cold storage

Lwin Hnin Phyu,Han Seung Yeon,Byeon Si-Eun,Lee Jinhee,Yoo Jingi,Jung Ha-il,이진욱 한국원예학회 2023 Horticulture, Environment, and Biotechnology Vol.64 No.4

Onion bulbs are typically stored at lower storage temperature for a long time, permitting their year-round availability in the market. The objective of this study was to evaluate the relationships among onion bulb quality, targeted major metabolites, and mineral nutrient contents in long-term cold-stored onion bulbs from four major diff erent commercial onion packinghouses. Bulb fresh and dry weight, fructose, glucose, citric acid, total phenolic compounds, and ABTS were highest in Muan, compared with the other packinghouses. The contents of K, Mn, Zn, and Cu, the ratios of K/Mg, K/Ca, and Mn/Ca, and the contents of total phenolic compounds, total fl avonoids, and total anthocyanins were highest in Hamyang, compared with the other packinghouses. The contents of individual free amino acids were most likely highest in Hamyang and Mungyeong packinghouses, compared with the other packinghouses. The overall responses of bulb quality, targeted major metabolites, and mineral nutrients substantially aff ected the diff erential expression pattern of principal component analysis among four commercial packinghouses. While fructose was positively correlated with glucose, it was negatively correlated with methionine, leucine, valine, isoleucine, and aspartic acid. Antioxidant activities in terms of ABTS and DPPH were negatively correlated with Mn but positively correlated with bulb dry weight, h o , and lightness. The collective results indicate that onion bulb quality was highly aff ected by commercial onion packinghouses, thus glucose and fructose were highly associated with amino acids and bulb dry weight with most bulb physiological parameters. Therefore, the commercial storage facility may play a pivotal role in the fl uctuation of targeted major metabolites and mineral nutrients after long-term cold storage.

Investigation of Ball Size Effect on Microstructure and Thermoelectric Properties of p-type BiSbTe by Mechanical Alloying

Lwin, May Likha,Yoon, Sang-min,Madavali, Babu,Lee, Chul-Hee,Hong, Soon-Jik The Korean Powder Metallurgy Institute 2016 한국분말재료학회지 (KPMI) Vol.23 No.2

P-type ternary $Bi_{0.5}Sb_{1.5}Te_3$ alloys are fabricated via mechanical alloying (MA) and spark plasma sintering (SPS). Different ball sizes are used in the MA process, and their effect on the microstructure; hardness, and thermoelectric properties of the p-type BiSbTe alloys are investigated. The phases of milled powders and bulks are identified using an X-ray diffraction technique. The morphology of milled powders and fracture surface of compacted samples are examined using scanning electron microscopy. The morphology, phase, and grain structures of the samples are not altered by the use of different ball sizes in the MA process. Measurements of the thermoelectric (TE) transport properties including the electrical conductivity, Seebeck coefficient, and power factor are measured at temperatures of 300-400 K for samples treated by SPS. The TE properties do not depend on the ball size used in the MA process.

Off-Line PD Diagnosis for Stator Winding of Rotating Machines Using a UWB Sensor

Lwin, Kyaw-Soe,Park, Noh-Joon,Kim, Hee-Dong,Ju, Young-Ho,Park, Dae-Hee The Korean Institute of Electrical Engineers 2008 Journal of Electrical Engineering & Technology Vol.3 No.2

We studied partial discharge detection by sensing electromagnetic waves emitted from the partial discharge source in an HV Rotating Machine using a UWB sensor. In this study, we design a new type of compact low frequency UWB sensor based on micro-strip technology. We also perform many experiments of offline and dismantled testing compared with the existing HFCT on stator winding of the HV generator. We mention the detailed design of a new compact UWB sensor along with the time domain PRPD pattern and frequency domain results of partial discharge in the stator winding of a 6.6kV rotating machine by offline testing performed in a laboratory.

Assessment of Teak (Tectona grandis Linn. f.) Provenance Tests in the Bago Yoma Region, Myanmar

Lwin, Ohn,Hyun, Jung-Oh,Yahya, Andi Fadly Korean Society of Forest Science 2010 한국산림과학회지 Vol.99 No.5

This study described the general pattern of genetic variation among ten teak (Tectona grandis Linn. f.) provenances in Myanmar and determined the most suitable seed sources for the plantation program in Bago Yoma region. Seeds of ten provenances were collected to cover the whole teak natural distribution in Myanmar and planted at four trial sites in Bago Yoma region in 1998. Seven years after planting, variation was assessed for growth, morphological characteristics and their correlation with geoclimatic factors. Statistical analysis using ANOVA revealed that there were significant differences in most of the traits measured among provenances, trial sites and provenance ${\times}$ site interaction at five percent level. A positive significant correlation (p<0.01) was found among most of the traits. The regression analyses between all traits and geoclimatic factors indicated the existence of ecoclinal variation in teak. Most of the traits were negatively correlated with the latitude while a positive significant correlation was found between longitude and C/B ratio, crown-diameter, average branch angle and leaf-remain. There was no significant correlation between the mean temperature and any other traits in this study. Furthermore, growth traits and crown diameter were positively correlated with the mean annual rainfall while negative correlation was found between the geographical distance and growth traits. Results indicate that the latitudinal pattern of teak genetic variations in growth performance was attributed to the limit of mean annual rainfall. Comparative assessment showed that local provenances were generally the best and could be use as suitable seed sources for the plantation program in the Bago Yoma region.