• Title/Summary/Keyword: Knowledge Structures

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Analytical Approach of Sliding Installation Method with Spar Structure

  • Lee, Jong-Hyun
    • Journal of Navigation and Port Research
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    • v.35 no.7
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    • pp.575-580
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    • 2011
  • It is important to understand the trajectory of structure in launching process because of the short time of launching process may result in unexpected accidents or damage to structures. The high risk of structural failure is not avoidable without the fully comprehension of changing forces in launching procedure. The commercial software can evaluate the motion of launching event in calm water condition but there is the limitation of research application because of the programmed commercial software. The launching process of the spar hull is suggested with stage concept that is divided into 10 stages in time domain. A force equilibrium diagram is derived for each stage where the changes of force vector and motion characteristics take place. In particular, the effects of changes in buoyancy and drag force due to the progressive submergence of the spar hull are taken into account by means of a touch length concept. The results contained in this paper provide the valuable information of the trajectory motion evaluation with suggested methods in spar launching process with sliding barge. Furthermore, the presented stage concept and touch length concept will provide basic knowledge for understanding launching process and help to develop further research area for launching analysis.

The Estimation of Economic Service Life on Manufacturing Equipments Which It Follows in Technological Obsolescence (제조설비의 기술진부화에 따른 경제적 내용연수 추정)

  • Cho, Jin-Hyung;Oh, Hyun-Seung;Lim, Taek;Jung, Su-Il;Lee, Jung-Youp;Kim, Byung-Keug
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.34 no.1
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    • pp.74-79
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    • 2011
  • Engineering valuation is a specialized discipline requiring expert knowledge and judgment, which scientifically estimates the economic value of industrial properties. By industrial properties, we mean engineering structures such as mines, factories, buildings, machines, and other industrial facilities as well as facilities of public enterprises. Particular industrial properties can have longer economic life if their performance is excellent and they are still suitable for current manufacturing needs. If not, its economic life will be shorter. As speed of technological progress becomes rapid, life-cycle and development period of a product is becoming shorter. In an industry characterized by rapid development of technology, industrial properties can become obsolescent faster. Even if they are in good working order, they could be no longer suitable for manufacturing new products based on radically different technology. In our research, we apply engineering approach to estimating functional economic life by factoring in technological obsolescence in such an industry.

A Study on New Business of the Food Service Industry (외식산업의 창업에 대한 연구)

  • 조병소
    • Journal of Applied Tourism Food and Beverage Management and Research
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    • v.9
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    • pp.273-302
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    • 1998
  • INTERNATIONAL MONITORY FUNDS wave swept the Economic structural insolvency lies one upon another with low growth, low trust, low prices, low interest and low employment as[2 down 3 up] phenomenons have been distinguished and low enterprise a control of structures due to forecasting 200 million unemployment, including 600 million unemployed the head of a family population have a difficulty in their life. Only way to give them hope is through the commencement of an enterprises to have 2nd career development. But end of 1995, 467,00 dining out companies have been established and recently business are in depression. There are many business conditions of change of business or reduce operations, if unemployment populations of 5%, 100,000 peoples doing the commencement of an enterprises, enormous number of dining out companies will be increased and the competition will be fierce, especially those who have short knowledge and experience doing the commencement of an enterprises have high failure than success which will give a problems to society. Our study is to make the commencement of an enterprise to reducing the faiure and to be successful for main point to successful commencement of an enterprise, the established can self capability and mental condition, the main important factor is types of industry selection, successful and those established who takes this conditions will very carefully inspect various matters by scientifically and rationally mind industrys propulsion graphs and open official fixture graphs will framing detail factors. One by inspect the reduction of failure, and successful commencement of an enterproses mind industry have been studied.

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Time Reversal Focusing and Imaging of Point-Like Defects in Specimens with Nonplanar Surface Geometry

  • Jeong, Hyun-Jo;Lee, Hyun-Kee;Bae, Sung-Min;Lee, Jung-Sik
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.6
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    • pp.569-577
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    • 2010
  • Nonplanar surface geometries of components are frequently encountered in real ultrasonic inspection situations. Use of rigid array transducers can lead to beam defocusing and reduction of defect image quality due to the mismatch between the planar array and the changing surface. When a flexible array is used to fit the complex surface profile, the locations of array elements should be known to compute the delay time necessary for adaptive heam focusing. An alternative method is to employ the time reversal focusing technique that does not require a prior knowledge about the properties and structures of the specimen and the transducer. In this paper, a time reversal method is applied to simulate beam focusing of flexible arrays and imaging of point-like defects contained in specimens with nonplanar surface geometry. Quantitative comparisons are made for the performance of a number of array techniques in terms of the ability to focus and image three point-like reflectors positioned at regular intervals. The sinusoidal profile array studied here exhibits almost the same image quality as the flat, reference case.

A New Intermediate in the Degradation of Carbofuran by Sphingomonas sp. Strain SB5

  • Park Myung-Ryeol;Lee Sun-Woo;Han Tae-Ho;Oh Byung-Tack;Shim Jae-Han;Kim In-Seon
    • Journal of Microbiology and Biotechnology
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    • v.16 no.8
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    • pp.1306-1310
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    • 2006
  • Sphingomonas sp. strain SB5 could degrade carbofuran and carbofuran-7-phenol to a hydrolytic product, 2-hydroxy-3-(3-methlypropan-2-o1)phenol, and several red metabolites. However, the chemical structures of the red metabolites have largely remained unidentified. In this study, we identified the structure of one of the red metabolites as 5-(2-hydroxy-2-methyl-propyl)-2,2-dimethyl- 2,3-dihydro-naphtho[2,3-6]furan-4,6,7,9-tetrone by using mass spectrometric and NMR ($^1$H, $^{13}$C) analyses. It is suggested that the red metabolite resulted from condensation of some metabolites in the degradation of 2-hydroxy-3-(3-methlypropan-2-o1)phenol, a hydrolytic product derived from carbofuran. To our knowledge, this is the first paper to report a red metabolite in bacterial degradation of the insecticide carbofuran.

Seismic fragility performance of skewed and curved bridges in low-to-moderate seismic region

  • Chen, Luke;Chen, Suren
    • Earthquakes and Structures
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    • v.10 no.4
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    • pp.789-810
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    • 2016
  • Reinforced concrete (RC) bridges with both skew and curvature are pretty common in areas with complex terrains. Existing studies have shown skewed and/or curved bridges exhibit more complicated seismic performance than straight bridges, and yet related seismic risk studies are still rare. These bridges deserve more studies in low-to-moderate seismic regions than those in seismic-prone areas. This is because for bridges with irregular and complex geometric designs, comprehensive seismic analysis is not always required and little knowledge about actual seismic risks for these bridges in low-to-moderate regions is available. To provide more insightful understanding of the seismic risks and the impact from the geometric configurations, analytical fragility studies are carried out on four typical bridge designs with different geometric configurations (i.e., straight, curved, skewed, skewed and curved) in the mountain west region of the United States. The results show the curved and skewed geometries can considerably affect the bridge seismic fragility in a complex manner, underscoring the importance of conducting detailed seismic risk assessment of skewed and curved bridges in low-to-moderate seismic regions.

Relative static and dynamic performances of composite conoidal shell roofs

  • Bakshi, Kaustav;Chakravorty, Dipankar
    • Steel and Composite Structures
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    • v.15 no.4
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    • pp.379-397
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    • 2013
  • Conoidal shells are doubly curved stiff surfaces which are easy to cast and fabricate due to their singly ruled property. Application of laminated composites in fabrication of conoidal shells reduces gravity forces and mass induced forces compared to the isotropic constructions due to the high strength to weight ratio of the material. These light weight shells are preferred in the industry to cover large column free open spaces. To ensure design reliability under service conditions, detailed knowledge about different behavioral aspects of conoidal shell is necessary. Hence, in this paper, static bending, free and forced vibration responses of composite conoidal shells are studied. Lagrange's equation of motion is used in conjunction with Hamilton's principle to derive governing equations of the shell. A finite element code using eight noded curved quadratic isoparametric elements is developed to get the solutions. Uniformly distributed load for static bending analysis and three different load time histories for solution of forced vibration problems are considered. Eight different stacking sequences of graphite-epoxy composite and two different boundary conditions are taken up in the present study. The study shows that relative performances of different shell combinations in terms of static behaviour cannot provide an idea about how they will relatively behave under dynamic loads and also the fact that the points of occurrence of maximum static and dynamic displacement may not be same on a shell surface.

Fundamental behavior of CFT beam-columns under fire loading

  • Varma, Amit H.;Hong, Sangdo;Choe, Lisa
    • Steel and Composite Structures
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    • v.15 no.6
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    • pp.679-703
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    • 2013
  • This paper presents experimental investigations of the fundamental behavior of concrete filled steel tube (CFT) beam-columns under fire loading. A total of thirteen specimens were tested to determine the axial force-moment-curvature-temperature behavior of CFT beam-columns. The experimental approach involved the use of: (a) innovative heating and control equipment to apply thermal loading and (b) digital image correlation with close-range photogrammetry to measure the deformations (e.g., curvature) of the heated region. Each specimen was sequentially subjected to: (i) constant axial loading; (ii) thermal loading in the expected plastic hinge region following the ASTM E119 temperature-time T-t curve; and (iii) monotonically increasing flexural loading. The effects of various parameters on the strength and stiffness of CFT beam-columns were evaluated. The parameters considered were the steel tube width, width-tothickness ratio, concrete strength, maximum surface temperature of the steel tube, and the axial load level on the composite CFT section. The experimental results provide knowledge of the fundamental behavior of composite CFT beam-columns, and can be used to calibrate analytical models or macro finite element models developed for predicting behavior of CFT members and frames under fire loading.

In-plane response of masonry infilled RC framed structures: A probabilistic macromodeling approach

  • De Domenico, Dario;Falsone, Giovanni;Laudani, Rossella
    • Structural Engineering and Mechanics
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    • v.68 no.4
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    • pp.423-442
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    • 2018
  • In this paper, masonry infilled reinforced concrete (RC) frames are analyzed through a probabilistic approach. A macro-modeling technique, based on an equivalent diagonal pin-jointed strut, has been resorted to for modelling the stiffening contribution of the masonry panels. Since it is quite difficult to decide which mechanical characteristics to assume for the diagonal struts in such simplified model, the strut width is here considered as a random variable, whose stochastic characterization stems from a wide set of empirical expressions proposed in the literature. The stochastic analysis of the masonry infilled RC frame is conducted via the Probabilistic Transformation Method by employing a set of space transformation laws of random vectors to determine the probability density function (PDF) of the system response in a direct manner. The knowledge of the PDF of a set of response indicators, including displacements, bending moments, shear forces, interstory drifts, opens an interesting discussion about the influence of the uncertainty of the masonry infills and the resulting implications in a design process.

Propulsion Technologies of Supercavitating Rocket Torpedo, Shkval (초공동 로켓 어뢰 Shkval 추진기술)

  • Kim, Yoon-Gon;Nah, Young-In
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.383-387
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    • 2011
  • The supercavitating rocket torpedo SHKVAL was analyzed in view of its system operation procedure and the structure and performance. 3 different propulsion systems installed in SHKVAL were 1st solid rocket booster for launch and acceleration, 2nd solid rocket booster for further acceleration, and Mg-rich Hydroreactive fuel rocket propulsion system for cruising. The gas generator used to help generate the supercavitation bubble was composed of a solid propellant gas generator and a hydroreactive fuel one. The structures and their performance were described based on as much knowledge as we have obtained from cumulative information and up-to-date analysis.

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