• Structural Engineering and Mechanics
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• v.89 no.1
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• pp.1-11
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• 2024

This article introduces a novel analytical model for examining the impact of porosity on shear correction factors (SCFs) in functionally graded porous beams (FGPB). The study employs uneven and logarithmic-uneven modified porosity-dependent power-law functions, which are distributed throughout the thickness of the FGP beams. Additionally, a modified exponential-power law function is used to estimate the effective mechanical properties of functionally graded porous beams. The correction factor plays a crucial role in this analysis as it appears as a coefficient in the expression for the transverse shear stress resultant. It compensatesfor the assumption that the shear strain is uniform across the depth of the cross-section. By applying the energy equivalence principle, a general expression for static SCFs in FGPBs is derived. The resulting expression aligns with the findings obtained from Reissner's analysis, particularly when transitioning from the two-dimensional case (plate) to the one-dimensional case (beam). The article presents a convenient algebraic form of the solution and provides new case studies to demonstrate the practicality of the proposed formulation. Numerical results are also presented to illustrate the influence of porosity distribution on SCFs for different types of FGPBs. Furthermore, the article validates the numerical consistency of the mechanical property changesin FG beams without porosity and the SCF by comparing them with available results.

• Structural Engineering and Mechanics
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• v.89 no.2
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• pp.181-197
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• 2024

A numerical method is presented in this paper, for buckling analysis of thin arbitrary stiffened composite cylindrical shells under axial compression. The stiffeners can be placed inside and outside of the shell. The shell and stiffeners are operated as discrete elements, and their interactions are taking place through the compatibility conditions along their intersecting lines. The governing equations of motion are obtained based on Koiter's theory and solved by utilizing the principle of the minimum potential energy. Then, the buckling load coefficient and the critical buckling load are computed by solving characteristic equations. In this formulation, the elastic and geometric stiffness matrices of a single curved strip of the shell and stiffeners can be located anywhere within the shell element and in any direction are provided. Moreover, five stiffened composite shell specimens are made and tested under axial compression loading. The reliability of the presented method is validated by comparing its numerical results with those of commercial software, experiments, and other published numerical results. In addition, by using the ANSYS code, a 3-D finite element model that takes the exact geometric arrangement and the properties of the stiffeners and the shell into consideration is built. Finally, the effects of Poisson's ratio, shell length-to-radius ratio, shell thickness, cross-sectional area, angle, eccentricity, torsional stiffness, numbers and geometric configuration of stiffeners on the buckling of stiffened composite shells with various end conditions are computed. The results gained can be used as a meaningful benchmark for researchers to validate their analytical and numerical methods.

• Advances in nano research
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• v.16 no.6
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• pp.623-638
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• 2024

This study investigates the thermal post-buckling behavior of concrete eccentric annular sector plates reinforced with graphene oxide powders (GOPs). Employing the minimum total potential energy principle, the plates' stability and response under thermal loads are analyzed. The Haber-Schaim foundation model is utilized to account for the support conditions, while the transform differential quadrature method (TDQM) is applied to solve the governing differential equations efficiently. The integration of GOPs significantly enhances the mechanical properties and stability of the plates, making them suitable for advanced engineering applications. Numerical results demonstrate the critical thermal loads and post-buckling paths, providing valuable insights into the design and optimization of such reinforced structures. This study presents a machine learning algorithm designed to predict complex engineering phenomena using datasets derived from presented mathematical modeling. By leveraging advanced data analytics and machine learning techniques, the algorithm effectively captures and learns intricate patterns from the mathematical models, providing accurate and efficient predictions. The methodology involves generating comprehensive datasets from mathematical simulations, which are then used to train the machine learning model. The trained model is capable of predicting various engineering outcomes, such as stress, strain, and thermal responses, with high precision. This approach significantly reduces the computational time and resources required for traditional simulations, enabling rapid and reliable analysis. This comprehensive approach offers a robust framework for predicting the thermal post-buckling behavior of reinforced concrete plates, contributing to the development of resilient and efficient structural components in civil engineering.

• Earthquakes and Structures
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• v.27 no.2
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• pp.143-154
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• 2024

Friction pendulums typically suffer from poor uplift-restraining. To improve the uplift-restraining and enhance the energy dissipation capacity, this article proposed a composite isolation device based on electromagnetic forces. The device was constructed based on a remote control system to achieve semi-active control of the composite isolation device. This article introduces the theory and design of an electromagnetic chuck-friction pendulum system (ECFPS) and derives the theoretical equation for the ECFPS based on Maxwell's electromagnetic attraction equation to construct the proposed model. By conducting 1:3 scale tests on the electromagnetic device, the gaps between the practical, theoretical, and simulation results were analyzed, and the accuracy and effectiveness of the theoretical equation for the ECFPS were investigated. The hysteresis and uplift-restraining performance of ECFPS were analyzed by adjusting the displacement amplitude, vertical load, and input current of the simulation model. The data obtained from the scale test were consistent with the theoretical and simulated data. Notably, the hysteresis area of the ECFPS was 35.11% larger than that of a conventional friction pendulum. Lastly, a six-story planar frame structure was established through SAP2000 for a time history analysis. The isolation performances of ECFPS and FPS were compared. The results revealed that, under horizontal seismic action, the horizontal seismic response of the bottom layer of the ECFPS isolation structure is greater than that of the FPS, the horizontal vibration response of the top layer of the ECFPS isolation structure is smaller than that of the FPS, and the axial force at the bottom of the columns of the ECFPS isolation structure is smaller than that of the FPS isolation structure. Therefore, the reliable uplift-restraining performance is facilitated by the electromagnetic force generated by the device.

• Steel and Composite Structures
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• v.52 no.3
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• pp.343-356
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• 2024

This paper presents an analytical solution for correctly predicting the Lateral-Torsional Buckling critical moment of simply supported castellated beams, the solution covers uniformly distributed loads combined with compressive loads. For this purpose, the castellated beam section with hexagonal-type perforation is treated as an arrangement of double "T" sections, composed of an upper T section and a lower T section. The castellated beam with regular openings is considered as a periodic repeating structure of unit cells. According to the kinematic model, the energy principle is applied in the context of geometric nonlinearity and the linear elastic behavior of materials. The differential equilibrium equations are established using Galerkin's method and the tangential stiffness matrix is calculated to determine the critical lateral torsional buckling loads. A Finite Element simulation using ABAQUS software is performed to verify the accuracy of the suggested analytical solution, each castellated beam is modelled with appropriate sizes meshes by thin shell elements S8R, the chosen element has 8 nodes and six degrees of freedom per node, including five integration points through the thickness, the Lanczos eigen-solver of ABAQUS was used to conduct elastic buckling analysis. It has been demonstrated that the proposed analytical solution results are in good agreement with those of the finite element method. A parametric study involving geometric and mechanical parameters is carried out, the intensity of the compressive load is also included. In comparison with the linear solution, it has been found that the linear stability underestimates the lateral buckling resistance. It has been confirmed that when high axial loads are applied, an impressive reduction in critical loads has been observed. It can be concluded that the obtained analytical solution is efficient and simple, and offers a rapid and direct method for estimating the lateral torsional buckling critical moment of simply supported castellated beams.

• Smart Structures and Systems
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• v.33 no.5
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• pp.365-374
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• 2024

This paper adopts a new approach in which nonlinear vibrations can be controlled using fuzzy controllers by optimal grey evolutionary algorithm. If the fuzzy controller cannot stabilize the systems, then the high frequency is injected into the system to assist the controller, and the system is asymptotically stabilized by adjusting the parameters. This paper uses the GM (grey model) and the neural network prediction model. The structure of the neural network is improved from a single factor, and multiple data inputs are extended to various factors and numerous data inputs. The improved model expands the applicable range of uncontrolled elements and improves the accuracy of controlled prediction, using the model that has been trained and stabilized by multiple learning. The simulation results show that the improved gray neural network model has higher prediction accuracy and reliability than the traditional GM model, improving controlled management and pre-control ability. In the combined prediction, the time series parameters and the predicted values obtained from the GM (1,1) (Grey Model of first order and one variable) are simultaneously used as the input terms of the neural network, considering the influence of the non-equal spacing of the data, which makes the results of the combined gray neural network model more rationalized. By adjusting the model structure and system parameters to simulate and analyze the controlled elements, the corresponding risk change trend graphs and prediction numerical calculation results are obtained, which also realize the effective prediction of controlled elements. According to the controlled warning principle and objective, the fuzzy evaluation method establishes the corresponding early warning response method. The goals of this paper are towards access to adequate, safe and affordable housing and basic services, promotion of inclusive and sustainable urbanization and participation, implementation of sustainable and disaster-resilient buildings, sustainable human settlement planning and manage.

• (The)Study of the Eastern Classic
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• no.56
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• pp.147-170
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• 2014

To divide by the concept of Cheon (天) before and after the period of Song Dynasty: before Song Dynasty; according to the ancient Book of Odes (Sigyeong-詩經), "Cheon (天) gives birth to a large number of people", and, Confucius(孔子) say "Cheon(天) gave me Virtue(德)." Mencius(孟子) say "The person done with all his heart knows Seong(性, personality), so if he knows such Seong(性, personality), then he knows Cheon(天)." In Doctrine of the Mean(中庸), it says "Cheon(天) ordered it to be called - Seong(性, personality)." So, Cheon(天) had a religious meaning, such as Sangje(上帝) - Supreme Ruler. During the Song period, Cheon(天), the source of its existence, had construed as Mugeuk i Taegeuk Non(無極而太極論 - Theory of Supreme Ultimate while being Indeterminate) and Theory of li and ki (iginon-理氣論). Juja (朱子, a honorary name of Juhui, 朱熹) had said a reasonable Cheon(天), that is, Heavenly Principle (天理 - Cheolli) by interpreting Cheon(天) as Taegeuk(太極 - Supreme Polarity) and li(理) of Muwi(無爲 - uncontrived action). That's why Juja had lost the religiosity because of his reasonable frame. The purpose of this dissertation is to identify of the quality of being religious of li(理) on the basis of attribute of Cheon(天) argued by Toegye and Juja. In the text of Seomyeong(西銘 - Western Inscription), we can see their interpretation of the content that Toegye as "西銘考證講義"(Lecture on Historical Research of Western Inscription), and Juja as "西銘解"(Commentary on the Western Inscription). Seomyeong(西銘 - Western Inscription) was expounded as a logic of 'iil bunsu' (理一分殊 - coherence is one and distinguished into many). '理一分殊' means to live in as meaningful as possible according to the human nature that has been bestowed upon thyself. Juja and Toegye both said that in the aspect of 'iil'(理一 - coherence is one), Reverence(事天) ought to be done, but to look into the aspect of 'bunsu'(分殊-distinguished into many), Juja argued that people should follow the order of Heavenly Principle(天理 - Cheolli), and Toegye argued that people should have to perform the filial piety(孝). There are differences in methods of Toegye and Juja on account of distinction between attributes of Cheon(天). Such a distinction affects the attribute of li(理). Juja said divisively that Soiyeon(所以然-why its principle is so) is li(理), and Sodangyeon(所當然-what should be so) is Sa(事-divine project). Toegye argued that Sodangyeon(所當然-what should be so) is indeed li(理). It is the position of Toegye that to know Seong(性-the personality) of Sodangyeon(所當然-what should be so) is the first, rather than to know Cheon(天) of Soiyeon(所以然-why its principle is so) that is out of reach in a faraway place. Seong(性-the personality) is li(理) that bestowed by Cheon(天). In view of discussion about the essence and existence, for Toegye, the existence is the first, rather than the essence. The issues of existence is now enabled to talk about amid the discussion of metaphysics, namely li(理). Different from Juja, a theory noticed in Toegye is the theory of 'Lijado'(理自到). 'Lijado'(理自到) denotes 'Li(理) leads on their own.' It tells that separate from thing-in-itself, there is an energy that moves and oversees the thing. This is an issue of response between "I" as the principal agent and other people. If "I" as the principal agent is sincere to others, the others will come to me insomuch as they will be revealed through me. Here, a problem between the host and guest arises. Toegye perceived this problem that do not see me and others as same, and also do not see me and others as two. This is the logic of 'ilii iiil'(一而二 二而一 - looks like one but two, looks like two but one) of '理一分殊' (coherence is one and distinguished into many). The first thing to do between these two processes is to recognize the existence of 'iil'(理一). Toegye strongly displays a religious attitude identifying Cheon(天)=Li (理)=Sangje(上帝- Supreme Ruler) in the same light.

• Journal of Korean Medical classics
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• v.6
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• pp.252-305
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• 1993

I have studied the relation between a Taoist(道家) and the oriental medicine(韓醫學), it is summerized as following. 1. According to the relation between a Taoist(道家) and the oriental medicine, Lao-tzu(老子)' mathematical principle that had an influence on Three yin-three yang(三陰三陽) theory of the oriental medicine, idea of natural philosopy(自然無爲) and the freedom from avarace(無慾) on the oriental medicine. 2. Vital essence and energy theory(精氣設) in a Taoist not only can be seen in Lao-tzu' Do dug gyung(老子道德經), Maengza(孟子), Guanza(管子), but also its principle has something to do with Nei Ching's Vital essence and energy theory(精氣設). 3. Danjungpa(丹鼎派) can be divided into Naedansul(內丹術) which preserves through the breath and Oedansul(外丹術) which makes one a Taoist hermit. If he takes magic portions(金丹), they had a great effect on Yangsanghak(養生學) and was actually concerned with oriental doctors who was known to us. 4. If medicine of Taoism is classified, it can be divided into three categories. Boiled solution(渴液), Pharmacopea "Ben cao"(本草), Acupuncture & moxibustion(針灸), Magic portions(外丹) are used in the first category. Chinese setting-up and Therapeutic exercises(導引), Josik(調息), Naedan(內丹), Byugok(辟榖), Naeshi(內視), Banjung(房中) belong to second category. The religious contents such as Bu(符), Jeum(占), Cheum(籤), Ju(呪), Je(齊), Gido(祈禱), taboo are implied in third category. 5. In the history of the medicine of Taoism and oriental medicine, they are called animism, shamanism, Mu(巫) or Ye(毉), not separated at first period. In the end of junguk(戰國時代), Ye(醫) was clearly distinguished from Mu(巫) and then Mu(巫) was developed into medicine of Taoism and ye(毉) into the present form of oriental medicine. 6. The oriental medicine doctors that are concerned with Taoism are Bakgo(伯高), Geyugu(鬼臾區), Soyu(少兪), Noigong(雷公), Pyujak(篇鵲), Sunuyi(淳于意), Hwata(華陀), Hwangbomil(皇甫謐), Hangang(韓康), Dongbong(童奉), Heuson(許遜), Galhong(葛洪), Dohongyung(陶弘景), Damlan(曇鸞), uyjajang(葦慈藏), Sonsanak(孫思邈), Wanguing(王氷), Jegonghwalbul(濟公活佛), Yuwanso(劉完素), Judonge(朱丹溪), Leesijin(李時珍), Johakmin(趙學敏), Ougu1(吳杰) etc. 7. The view of a human body in the medicine of Taoism affected the oriental medicine on the ground that man was regarded as a microcosm(小宇宙), so he was compared to a nation or heaven and earth. 8. The anatomy of medicine of Taoism gave a detail description of five visceras and each organs, the heart, center of mental function, Mirie(尾閭) which has an relationship to the training of Naedan(內丹修練). In this resrect, as it is accord with the acupunture point of oriental medicine, therefore we can find that Taoism influenced oriental medicine, also explicit study was achieved. 9. Acient people believed that the goo in the human lxxIy, one of the characteristics of the medicine of Taoism cured the patients and then protected him from the disease. If a man was taken ill, they had him cured by making the god's name which corresponded to its disease, calling him communicating with him, and asking him to deprive him of illness. This treatment was used to live and be kept young eternally. In this respects, we can see that they emphasized on the attitude of Bulchiyibeung chimibeung(不治己病治末病) and psychological treatment. 10. Samsi thoery(三尸說) that one's fortune, disaster, health, and disease in the world are at the mercy of his good or bad conduct, is concerned with Taoism and treatment with the oriental medicine. 11. Guchung(九蟲) is more closly associated with the religious aspect rather than with the medical aspect. Because of the similarity of the mcdern parasitism, its study has an important meaning. 12. The respect for the human life is reflected in jeunsi(傳屍), with Samsi-guchung theory(三尸九蟲說), which is considered as mxIern tuberculosis.

• Journal of Acupuncture Research
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• v.33 no.2
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• pp.135-150
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• 2016

Objectives : The aim of this study is to review the combination effects and adverse effects of Yerba Mate (Ilex paraguariensis) on the treatment of obesity. Methods : Four databases were searched, including Pubmed, National assembly library, RISS4u, and NDSL, for studies published before March 31, 2016 using the keywords 'yerba mate', 'Ilex paraguariensis', and those related to 'obesity'. Clinical trials, and both in vivo and in vitro studies were classified according to the following categories: publication year, nationality, types and composition of test compounds, combination effects, adverse effects, and safety. Results : A total of 16 articles (14 clinical trials, one in vivo, one in vitro) were included in the analysis. Combination effects were reported from six YGD (Yerba Mate, Guarana, Damiana, Zotrim), five Meltdown, one Shred-matrix, one DBX (DymaBurn Xtreme), one XSIII research study, and adverse effects were reported from two YGD (Zotrim), four Meltdown, one Shred-matrix and one MetEF research study. YGD and Shred-matrix increased satiety while YGD and MetEF had adverse gastrointestinal effects potentially due to guarana. Meltdown and Shred-matrix increased energy expenditure and fat oxidation and had the adverse effects of increased heart rate and blood pressure due to the thermogenic effect of caffeine and yohimbine. DBX increased resting energy expenditure but no difference was observed in respiratory exchange ratio. XSIII reduced body weight gain and food intake more than each of the extracts did on their own. Conclusion : Taken together, the combination effects and adverse effects differed according to the composition of test compounds and the ratio of ingredients. Multicomponent approaches should be used for treating multifactorial diseases such as obesity. As a general conclusion, there is a place for a combination of herbal components including yerba mate, based on the principle of Kun-Shin-Choa-Sa for the treatment of obesity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.37-43
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• 2017

This review investigates the basic principle of physical interactions and failure mechanisms introduced in the materials and inner parts of semiconducting components under electromagnetic pulses (EMPs). The transfer process of EMPs at the semiconducting component level can be explained based on three layer structures (air, dielectric, and conductor layers). The theoretically absorbed energy can be predicted by the complex reflection coefficient. The main failure mechanisms of semiconductor components are also described based on the Joule heating energy generated by the coupling between materials and the applied EMPs. Breakdown of the P-N junction, burnout of the circuit pattern in the semiconductor chip, and damage to connecting wires between the lead frame and semiconducting chips can result from dielectric heating and eddy current loss due to electric and magnetic fields. To summarize, the EMPs transferred to the semiconductor components interact with the chip material in a semiconductor, and dipolar polarization and ionic conduction happen at the same time. Destruction of the P-N junction can result from excessive reverse voltage. Further EMP research at the semiconducting component level is needed to improve the reliability and susceptibility of electric and electronic systems.