• Title/Summary/Keyword: Critical Theory

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Isogeometric thermal postbuckling of FG-GPLRC laminated plates

  • Kiani, Y.;Mirzaei, M.
    • Steel and Composite Structures
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    • v.32 no.6
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    • pp.821-832
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    • 2019
  • An analysis on thermal buckling and postbuckling of composite laminated plates reinforced with a low amount of graphene platelets is performed in the current investigation. It is assumed that graphaene platelets are randomly oriented and uniformly dispersed in each layer of the composite media. Elastic properties of the nanocomposite media are obtained by means of the modified Halpin-Tsai approach which takes into account the size effects of the graphene reinforcements. By means of the von $K{\acute{a}}rm{\acute{a}}n$ type of geometrical nonlinearity, third order shear deformation theory and nonuniform rational B-spline (NURBS) based isogeometric finite element method, the governing equations for the thermal postbuckling of nanocomposite plates in rectangular shape are established. These equations are solved by means of a direct displacement control strategy. Numerical examples are given to study the effects of boundary conditions, weight fraction of graphene platelets and distribution pattern of graphene platelets. It is shown that, with introduction of a small amount of graphene platelets into the matrix of the composite media, the critical buckling temperature of the plate may be enhanced and thermal postbuckling deflection may be alleviated.

On buckling analysis of laminated composite plates using a nonlocal refined four-variable model

  • Shahsavari, Davood;Karami, Behrouz;Janghorban, Maziar
    • Steel and Composite Structures
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    • v.32 no.2
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    • pp.173-187
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    • 2019
  • This study is concerned with the stability of laminated composite plates modelled using Eringen's nonlocal differential model (ENDM) and a novel refined-hyperbolic-shear-deformable plate theory. The plate is assumed to be lying on the Pasternak elastic foundation and is under the influence of an in-plane magnetic field. The governing equations and boundary conditions are obtained through Hamilton's principle. An analytical approach considering Navier series is used to fine the critical bucking load. After verifying with existing results for the reduced cases, the present model is then used to study buckling of the laminated composite plate. Numerical results demonstrate clearly for the first time the roles of size effects, magnetic field, foundation parameters, moduli ratio, geometry, lay-up numbers and sequences, fiber orientations, and boundary conditions. These results could be useful for designing better composites and can further serve as benchmarks for future studies on the laminated composite plates.

Conceptual Shift of Archival Management in Digital Environment (전자환경에서의 기록관리 개념에 관한 재검토)

  • Lee, Seung-eok
    • The Korean Journal of Archival Studies
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    • no.6
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    • pp.41-72
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    • 2002
  • Electronic environment affects archival community to a great extent. It redefines virtually every stage of archival management form creation to current and semi-current use, to appraisal, and to preservation of records. Faced with the problems caused by ever increasing electronic records, the community is forced to reconsider traditional concepts, approaches, methodologies, even the basic paradigm embedded in archival theory and practice. The present paper discusses the need to reexamine principles and techniques of archival management in the light of digital environment. It also urges archives and archival institutions, the archival profession, or the archival community at large, to participate in this critical enterprise. Success in this endeavor will, eventually, pave the road toward creating, organizing, providing access to, preserving reliably and authentically electronic records and designing proper system for the societal collective memory in recorded digital information.

Knowledge and Technology Resources for Knowledge Management Practices of Nonprofit Organizations in Thailand

  • Le, Quang Ngoc;Tuamsuk, Kulthida
    • Journal of Information Science Theory and Practice
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    • v.9 no.3
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    • pp.42-55
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    • 2021
  • Knowledge and technology resources are the most crucial sources for the achievement of sustainable development in competitive advantage. Meanwhile, few empirical studies have clarified the types of knowledge and technology resources that nonprofit organizations (NPOs) use and develop. This study aims to categorize knowledge and technology resources in NPOs that both researchers and practitioners can use to develop the nonprofit sector further. A qualitative research method was used for the study. Data were collected from 31 interviews with senior and founding members of NPOs in Thailand. Analysis of qualitative data identified five critical categories of knowledge resources: human resources, organizational practices, partnership or stakeholder involvement, operational practices, and other resources. This study also illustrates both internal and external technology resources, which are used in sample organizations. The study's findings contribute to developing a body of knowledge management literature related to the knowledge and technology resources of NPOs.

Analysis on the buckling of imperfect functionally graded sandwich plates using new modified power-law formulations

  • Zohra, Abdelhak;Benferhat, Rabia;Tahar, Hassaine Daouadji;Tounsi, Abdelouahed
    • Structural Engineering and Mechanics
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    • v.77 no.6
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    • pp.797-807
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    • 2021
  • A new simple solution for critical buckling of FG sandwich plates under axial and biaxial loads is presented using new modified power-law formulations. Both even and uneven distributions of porosity are taken into account in this study. Material properties of the sandwich plate faces are assumed to be graded in the thickness direction according to a modified power-law distribution in terms of the volume fractions of the constituents. Equilibrium and stability equations of FG sandwich plate with various boundary conditions are derived using the higher-order shear deformation plate theory. The results reveal that the distribution shape of the porosity, the gradient index, loading type and functionally graded layers thickness have significant influence on the buckling response of functionally graded sandwich plates.

Death and the Inoperative Community in the Works of Gabriel Garcia Marquez and Merlinda Bobis

  • Prado, John Andrew M. del
    • SUVANNABHUMI
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    • v.14 no.1
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    • pp.229-246
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    • 2022
  • Gabriel García Márquez's short story "The Handsomest Drowned Man in the World" ["El ahogado más hermoso del mundo," 1968] and the novel Chronicle of a Death Foretold [Crónica de una muerte anunciada, 1981] and Merlinda Bobis's novel Fish-Hair Woman (2012) and short story "O Beautiful Co-Spirit" (2021) feature unusual scenarios of death: the arrival of a drowned man's corpse at an island; the inaction of the community to stop the foretold death of a supposedly-innocent man; a woman with long hair that can fetch dead bodies at the bottom of the village river; and a Filipino Catholic and a Malaysian Muslim working together to prepare an Italian Catholic's corpse for a funeral. These narratives demand critical attention as all deaths make the community's existence meaningful as they alter its social reality. Looking into the works of the aforementioned Colombian writer and Filipino writer and unveiling how death affects the community, this paper relies on Jean-Luc Nancy's theory on death and inoperative community.

Fuzzy FMECA analysis of radioactive gas recovery system in the SPES experimental facility

  • Buffa, P.;Giardina, M.;Prete, G.;De Ruvo, L.
    • Nuclear Engineering and Technology
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    • v.53 no.5
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    • pp.1464-1478
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    • 2021
  • Selective Production of Exotic Species is an innovative plant for advanced nuclear physic studies. A radioactive beam, generated by using an UCx target-ion source system, is ionized, selected and accelerated for experimental objects. Very high vacuum conditions and appropriate safety systems to storage exhaust gases are required to avoid radiological risk for operators and people. In this paper, Failure Mode, Effects, and Criticality Analysis of a preliminary design of high activity gas recovery system is performed by using a modified Fuzzy Risk Priority Number to rank the most critical components in terms of failures and human errors. Comparisons between fuzzy approach and classic application allow to show that Fuzzy Risk Priority Number is able to enhance the focus of risk assessments and to improve the safety of complex and innovative systems such as those under consideration.

Thermal-magneto-mechanical stability analysis of single-walled carbon nanotube conveying pulsating viscous fluid

  • R. Selvamani;M. Mahaveer Sree Jayan;Marin Marin
    • Coupled systems mechanics
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    • v.12 no.1
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    • pp.21-40
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    • 2023
  • In thisstudy, the vibration problem ofthermo elastic carbon nanotubes conveying pulsating viscous nano fluid subjected to a longitudinal magnetic field is investigated via Euler-Bernoulli beam model. The controlling partial differential equation of motion is arrived by adopting Eringen's non local theory. The instability domain and pulsation frequency of the CNT is obtained through the Galerkin's method. The numerical evaluation of thisstudy is devised by Haar wavelet method (HWM). Then, the proposed model is validated by analyzing the critical buckling load computed in presentstudy with the literature. Finally, the numerical calculation ofsystem parameters are shown as dispersion graphs and tables over non local parameter, magnetic flux, temperature difference, Knudsen number and viscous parameter.

Buckling analysis of a sandwich plate with polymeric core integrated with piezo-electro-magnetic layers reinforced by graphene platelets

  • Pooya, Nikbakhsh;Mehdi, Mohammadimehr
    • Advances in materials Research
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    • v.11 no.4
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    • pp.331-349
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    • 2022
  • In the present work, we proposed an analytical study on buckling behavior of a sandwich plate with polymeric core integrated with piezo-electro-magnetic layers such as BaTiO3 and CoFe2O4 reinforced by graphene platelets (GPLs). The Halpin-Tsai micromechanics model is used to describe the properties of the polymeric core. The governing equations of equilibrium are obtained from first-order shear deformation theory (FSDT) and the Navier's method is employed to solve the equations. The results show the effect of different parameters such as thickness, length, weight fraction of GPLs, and also effect of electric and magnetic field on critical buckling load. The result of this study can be obtained in the aerospace industry and also in the design of sensors and actuators.

CAN TRUST BETWEEN AN OWNER AND A CONTRACTOR BE ESTABLISHED: A PRINCIPAL-AGENT PERSPECTIVE

  • Jiang-wei Xu;Sungwoo Moon
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.1474-1478
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    • 2009
  • The cooperation and trust among the project participants play a critical role in the success or failure of any delivery system in construction industry. But it is very difficult to establish trust between an owner and a contractor when rational people only pursue only their own material self-interest. Based on the principal-agent theory, this paper will introduce the altruistic behavior into the traditional principal-agent model, and model the reciprocal behavior between the owner and contractor. We will show that both the owner and the contractor benefit from their reciprocal behavior, and hence trust establishing between them is possible. More importantly, we will proof that the higher the project uncertainty is, the more important trust establishing is.

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