• Title/Summary/Keyword: negative spring

Search Result 227, Processing Time 0.027 seconds

Buckling response of smart plates reinforced by nanoparticles utilizing analytical method

  • Farrokhian, Ahmad
    • Steel and Composite Structures
    • /
    • v.35 no.1
    • /
    • pp.1-12
    • /
    • 2020
  • This article deals with the buckling analysis in the plates containing carbon nanotubes (CNTs) subject to axial load. In order to control the plate smartly, a piezoelectric layer covered the plate. The plate is located in elastic medium which is modeled by spring elements. The Mori-Tanaka low is utilized for calculating the equivalent mechanical characteristics of the plate. The structure is modeled by a thick plate and the governing equations are deduced using Hamilton's principle under the assumption of higher-order shear deformation theory (HSDT). The Navier method is applied to obtain the bulking load. The effects of the applied voltage to the smart layer, agglomeration and volume percent of CNT nanoparticles, geometrical parameters and elastic medium of the structure are assessed on the buckling response. It has been demonstrated that by applying a negative voltage, the buckling load is increased significantly.

Analysis of Correlations between Mineral Contents in Waters and Sensory Characteristics of Coffee (물의 미네랄 함량과 커피 관능 특성에 관한 상관 분석)

  • Eo, Hee-Ji;Kim, Joo-Shin
    • Culinary science and hospitality research
    • /
    • v.23 no.4
    • /
    • pp.105-115
    • /
    • 2017
  • Water is an essential ingredient to brew coffee. Mineral contents in the water can affect both water quality and taste quality of coffee. The effects of minerals in the water on sensory characteristics of coffee were investigated in different water samples (A: Arisu, B: Claris, C: Spring water, D: Samdasoo, E: Evian, Distilled water as control). Based on the results of quantitative descriptive analysis (QDA), there were statistically significant (p<0.01) in flavor, acidity, bitterness, sweetness, body and aftertaste according to different water samples used to brew coffee. The canonical correlation analysis of minerals (Ca, Mg, Na, K) and taste (acidity, bitterness, sweetness) indicated that there were highly correlated in the relationship between bitterness and Mg content. A strong negative relationship was shown between bitterness and acidity, sweetness. A result of preference test using hedonic scale showed an inverse linear relationship between taste quality and total mineral contents.

Mathematical modeling of smart nanoparticles-reinforced concrete foundations: Vibration analysis

  • Kargar, Masood;Bidgoli, Mahmood Rabani
    • Steel and Composite Structures
    • /
    • v.27 no.4
    • /
    • pp.465-477
    • /
    • 2018
  • In this research, vibration and smart control analysis of a concrete foundation reinforced by $SiO_2$ nanoparticles and covered by piezoelectric layer on soil medium is investigated. The soil medium is simulated with spring constants and the Mori-Tanaka low is used for obtaining the material properties of nano-composite structure and considering agglomeration effects. With considering first order shear deformation theory, the total potential energy of system is calculated and by means of Hamilton's principle in three displacement directions and electric potential, the six coupled equilibrium equations are obtained. Also, based an analytical method, the frequency of system is calculated. The effects of applied voltage, volume percent and agglomeration of $SiO_2$ nanoparticles, soil medium and geometrical parameters of structure are shown on the frequency of system. Results show that with applying negative voltage, the frequency of structure is increased.

Airborne Microorganisms of Some Underground Shops in Pusan (부산시 일부 지하상가 공기중 부유 균주)

  • 이용환;정석훈;고광욱;김영기;변주현
    • Journal of Life Science
    • /
    • v.10 no.1
    • /
    • pp.74-78
    • /
    • 2000
  • This study was investigated to evaluate the distribution of airborne microorganisms at underground shops in Seomyun and Nampodong, Pusan. The number of bacterial colonies on the nutrient agar plate plates were calculated by the open petri dish method for 30 minutes in indoor air of underground shops at every seasons in a year. There was no statistically significant difference between Seomyun and Nampodong in mean colony counts. Isolation rates of Gram positive rods was highest, and Gram positive cocci and Gram negative rods were followed. In Nampodong underground shops, Enterobacteriaceae strains was isolated. Mean colony counts according to seasons was higher at summer and autumn in Seomyun, and spring and winter in Nampodong. In near future, a study on the distribution of bacteria causing respiratory infection should be followed.

  • PDF

Design Proposals of Public Architecture for Sustainable Development in Kwangju Old City (광주도심지역의 지속가능한 개발을 위한 공공건축 설계프로젝트)

  • 손승광
    • Proceeding of Spring/Autumn Annual Conference of KHA
    • /
    • 2002.11a
    • /
    • pp.79-84
    • /
    • 2002
  • Many people think, in common that An expansion toward outer city is a development, and it can be a general trends in a new development in a growing city. But We can see many case which moving of a public building are considerate as a core element to promote the new development towards outer city, and that is a negative element of slum in central area and community making. There are many aspects to pursue sustainable urban structure of in a city, and public building is a very important element to manage deteriorate central area from social slum in a old town. In this presentation, three project, Local Authority office of Chonnam province, Kwangju Station, and Hyper Urbanity, and it shows sustainable concept of the public building as a core in a city development. The effect of the projects are expected sustainable development and community in terms of social, cultural and historical aspects.

  • PDF

A Study of Apartment Exterior Space Plan by Child Play Area Special Quality (아동 놀이 영역 특성에 따른 아파트 외부공간 계획에 관한 연구)

  • Kim, Jae-Kyun;Lee, Jae-Hoon
    • Proceeding of Spring/Autumn Annual Conference of KHA
    • /
    • 2005.11a
    • /
    • pp.255-258
    • /
    • 2005
  • Currently open spaces of an apartment housing complex are considered in Korea as a negligible live Place that only contributes to enlarge its construction capacity of an apartment without taking its effects on the living quality into account. This trend reduces outdoor playing activities of the children who are the main users of open spaces and consequently has a negative influence on the child's growth. Therefore it is a imminent problem that we should provide open space utilizing plans on the basis of the study upon the types of the children's playing activities within the residential environment. The study purpose is finding about an outside activity of the child takes any influence according to an apartment disposition format.

  • PDF

A Study on the Characteristics of Court Housing Design in Korea (중정형 공동주택의 공간계획 특성 연구)

  • Kang, In-Ho;Park, So-Young
    • Proceeding of Spring/Autumn Annual Conference of KHA
    • /
    • 2005.11a
    • /
    • pp.263-268
    • /
    • 2005
  • The aim of this study was to analyse the design characteristics of court housing. In spite of changes of housing design condition, especially density, there have been changes only in the height of housing block, not in the housing types, layout system and other design properties. Due to the situation, housing design in Korea has been criticised as too routine and monotonous one. As one of the alternatives to respond to the criticism, this study focused on the positive aspects of the court housing type, and suggested the design strategies throughout the analysis of 8 entries in the design competition of EunPyeong NewTown, which attempted to overcome the negative problems - mainly the daylighting, orientation, and privacy- of this housing type. Throughout the analysis, there suggested design strategies to respond to the problems of court housing type, which can be the basis for the court housing design in Korea.

  • PDF

Housing status and Senior Services corresponding to Life Styles of the Middle aged (중년층의 라이프스타일 유형에 따른 주거조건 및 노후서비스)

  • Kim, Han-Na;Yoon, Chung-Sook
    • Proceeding of Spring/Autumn Annual Conference of KHA
    • /
    • 2005.11a
    • /
    • pp.79-84
    • /
    • 2005
  • The purpose of this study was to classify the middle aged corresponding to their Life Styles and analyze the senior housing types and services. the specific objectives of this study are as follows : First, analyze the specific of demography. Second classify the Life Style of the middle aged. Third, analyze the housing types and services that are classified. In analyzing the collected data, the frequency, factor analysis, cronbach's a, cluster analysis(K-means), X$^2$ ANOVA conducted within the SPSS 12.0. The Life Style were segmented four group : Actively outgoing group, self-confidence familial group, self-uncertainty responsible group, unsociable negative group. This study shows that the segmentation group's preference of senior housing types and services is different by the Life Style.

  • PDF

Consumer's Clothing Brand Loyalty and Clothing Buying Behavior (소비자의 의복 상표충성도와 의복구매행동)

  • 김순아;이영신
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.19 no.4
    • /
    • pp.602-614
    • /
    • 1995
  • The purposes of this study were 1) to reveal the consumer's brand loyalty on clothing, 2) to identify the relationships between the consumer's clothing brand loyalty and consumer characteristics, product characteristics, and consumer's clothing buying behavior. Subjects were selected from the employed and unemployed housewives living in Taejon. A questionnaire was developed and administered by 316 housewives during Spring in 1992. Data were analysed by frequency, Pearson's correlation coefficient, regression and oneway- ANOVA. The result.; of the study were as follows: 1) The half of subjects had brand loyalty on clothing. 2) The relationships between consumer's clothing brand loyalty and housewives' and her husbands 'educational level and average income of a month were significant. Consumer's clothing brand loyalty and housewives 'age had significantly negative relationship. 3) Consumer's clothing brand loyalty was significantly related to price of clothing. 4) The relationships between consumer's clothing brand loyalty and satisfaction toward brands, and the store patronage behavior were significant. The relationships between consumer's clothing brand loyalty and her prepurchase information search behavior, and the amount of purchasing of clothing were not significant.

  • PDF

A Study on Lateral Vibration at the Tail of Train for KTX (KTX 차량의 후미 횡 진동에 관한 연구)

  • Kim Jae-Chul;Lee Chan-Woo
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2005.10a
    • /
    • pp.6-11
    • /
    • 2005
  • During the acceptance test of KTX, lateral vibration of carbody at the tail of the train was found. The carbody lateral vibration was occurred on a straight line in the winter season. We analysis to find the cause of the lateral vibration and the countermeasure. The analysis results show that lateral stiffness of air spring is the most important parameter to cause the carbody lateral vibration. The lateral vibration is occurred at frequency range $0.5{\sim}0.6Hz$ with a negative damping value. We also blow that natural frequency of lateral vibration increase with the train speed up to 1Hz at 300km/h.

  • PDF