• Title/Summary/Keyword: CUF

Search Result 35, Processing Time 0.028 seconds

Effect of Weld Residual Stress on Fatigue Analysis of Nozzle (노즐의 피로해석에 미치는 용접잔류응력의 영향)

  • Kim, Sang-Chul;Kim, Man-Won
    • Journal of Welding and Joining
    • /
    • v.32 no.1
    • /
    • pp.71-78
    • /
    • 2014
  • Although the fatigue design curve of ASME Code has enough margin with respect to alternating stress and cycles, the welding residual stress(WRS) should be included in fatigue analysis. In this paper, WRS distribution in a nozzle with dissimilar metal weldment was obtained by finite element analysis and was added in fatigue analysis. The fatigue analysis was performed by following the ASME Code including thermal and stress analysis applying with postulated 30 transient conditions. The calculated results of a cumulative fatigue usage factors(CUF) were compared for the case of the models with or without WRS effects. The results showed that the CUF at weldment and heat affected zone was affected by the WRS.

Standardization and Development of Pharmacopoeial Standard Operating Procedures (SOPs) of Classical Unani Formulation

  • Mannan, Mohd Nazir;Kazmi, Munawwar Husain;Zakir, Mohammad;Naikodi, Mohammed Abdul Rasheed;Zahid, Uzma;Siddiqui, Javed Inam
    • CELLMED
    • /
    • v.10 no.2
    • /
    • pp.16.1-16.8
    • /
    • 2020
  • Standardization of drug deals with confirmation of drug identity and determination of drug quality and purity. Unani herbal formulations are used in traditional medicine for the treatment of various diseases. Cancer is a disease which causes abnormal, uncontrolled growth of body tissue or cells, which tend to proliferate in an uncontrolled way. Spread of cancer from site of origin to other organs of the body is called metastasis. It is a hyper proliferative disorder involving, transformation, dysregulation of apoptosis, invasion and angiogenesis. The present study aimed to standardize a classical Unani formulation (CUF) described as anticancer properties. The CUF has been used for anti-cancerous activity (Dāfi'-i-saraṭān) in human population by Unani physicians for centuries. The standardization parameters carried out for classical Unani formulation are pharmacognostical studies, physicochemical parameters, high-performance thin layer chromatography (HPTLC), microbial load, aflatoxins, and heavy metals revealing specific identities and to evaluate Pharmacopoeial standards. Experiment and the data obtained established the Pharmacopoeial standards for this formulation for identification and quality control purpose. The CUF has been successfully standardized and standard operating procedures (SOPs) for its preparation has been laid down which may serve as a standard reference in future. The standardization data of this formulation may be used as a standard guideline for preparation of the formulation in future.

Prognostic Value of Preoperative Serum CA 242 in Esophageal Squamous Cell Carcinoma Cases

  • Feng, Ji-Feng;Huang, Ying;Chen, Qi-Xun
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.14 no.3
    • /
    • pp.1803-1806
    • /
    • 2013
  • Purpose: Carbohydrate antigen (CA) 242 is inversely related to prognosis in many cancers. However, few data regarding CA 242 in esophageal cancer (EC) are available. The aim of this study was to determine the prognostic value of CA 242 and propose an optimum cut-off point in predicting survival difference in patients with esophageal squamous cell carcinoma (ESCC). Methods: A retrospective analysis was conducted of 192 cases. A receiver operating characteristic (ROC) curve for survival prediction was plotted to verify the optimum cuf-off point. Univariate and multivariate analyses were performed to evaluate prognostic parameters for survival. Results: The positive rate for CA 242 was 7.3% (14/192). The ROC curve for survival prediction gave an optimum cut-off of 2.15 (U/ml). Patients with CA 242 ${\leq}$ 2.15 U/ml had significantly better 5-year survival than patients with CA 242 >2.15 U/ml (45.4% versus 22.6%; P=0.003). Multivariate analysis showed that differentiation (P=0.033), CA 242 (P=0.017), T grade (P=0.004) and N staging (P<0.001) were independent prognostic factors. Conclusions: Preoperative CA 242 is a predictive factor for long-term survival in ESCC, especially in nodal-negative patients. We conclude that 2.15 U/ml may be the optimum cuf-off point for CA 242 in predicting survival in ESCC.

Nonhomogeneous atherosclerotic plaque analysis via enhanced 1D structural models

  • Varello, Alberto;Carrera, Erasmo
    • Smart Structures and Systems
    • /
    • v.13 no.4
    • /
    • pp.659-683
    • /
    • 2014
  • The static analysis of structures with arbitrary cross-section geometry and material lamination via a refined one-dimensional (1D) approach is presented in this paper. Higher-order 1D models with a variable order of expansion for the displacement field are developed on the basis of Carrera Unified Formulation (CUF). Classical Euler-Bernoulli and Timoshenko beam theories are obtained as particular cases of the first-order model. Numerical results of displacement, strain and stress are provided by using the finite element method (FEM) along the longitudinal direction for different configurations in excellent agreement with three-dimensional (3D) finite element solutions. In particular, a layered thin-walled cylinder is considered as first assessment with a laminated conventional cross-section. An atherosclerotic plaque is introduced as a typical structure with arbitrary cross-section geometry and studied for both the homogeneous and nonhomogeneous material cases through the 1D variable kinematic models. The analyses highlight limitations of classical beam theories and the importance of higher-order terms in accurately detecting in-plane cross-section deformation without introducing additional numerical problems. Comparisons with 3D finite element solutions prove that 1D CUF provides remarkable three-dimensional accuracy in the analysis of even short and nonhomogeneous structures with arbitrary geometry through a significant reduction in computational cost.

Free vibration analysis of damaged beams via refined models

  • Petrolo, Marco;Carrera, Erasmo;Alawami, Ali Saeghier Ali Saeed
    • Advances in aircraft and spacecraft science
    • /
    • v.3 no.1
    • /
    • pp.95-112
    • /
    • 2016
  • This paper presents the free vibration analysis of damaged beams by means of 1D (beam) advanced finite element models. The present 1D formulation stems from the Carrera Unified Formulation (CUF), and it leads to a Component-Wise (CW) modelling. By means of the CUF, any order 2D and 1D structural models can be developed in a unified and hierarchical manner, and they provide extremely accurate results with very low computational costs. The computational cost reduction in terms of total amount of DOFs ranges from 10 to 100 times less than shell and solid models, respectively. The CW provides a detailed physical description of the real structure since each component can be modelled with its material characteristics, that is, no homogenization techniques are required. Furthermore, although 1D models are exploited, the problem unknown variables can be placed on the physical surfaces of the real 3D model. No artificial surfaces or lines have to be defined to build the structural model. Global and local damages are introduced by decreasing the stiffness properties of the material in the damaged regions. The results show that the proposed 1D models can deal with damaged structures as accurately as a shell or a solid model, but with far lower computational costs. Furthermore, it is shown how the presence of damages can lead to shell-like modal shapes and torsional/bending coupling.

Four Pollution and Safe Measure in Building Demolition (구조물폭파공법 시공시 발파공해 안전대책 - 소음.진동.분진.비석공해를 중심으로 -)

  • 안명석
    • Journal of the Korean Society of Safety
    • /
    • v.8 no.3
    • /
    • pp.91-104
    • /
    • 1993
  • This paper is on the current and prospect of the most advanced explosive technics, special explosive technics. Futhermore, utmost needed and utmost centered interesting basic theory, struction explosive demolition is descirbed with counter Plan on the Problems of carrying out example and cuf out of it. Specified description noted on the four pollution especially noisy vibration, dust and disperse pollution with comprehensive counter plan. Although it has some insufficiency. I expect my paper will be to advance the explosive technics.

  • PDF

Accurate Free Vibration Analysis of Launcher Structures Using Refined 1D Models

  • Carrera, Erasmo;Zappino, Enrico;Cavallo, Tommaso
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.16 no.2
    • /
    • pp.206-222
    • /
    • 2015
  • This work uses different finite element approaches to the free vibration analysis of reinforced shell structures, and a simplified model of a typical launcher with two boosters is used as an example. The results obtained using a refined one-dimensional (1D) beam model are compared to those obtained with commercial finite element software. The 1D models that are used in the present work are based on the Carrera Unified Formulation (CUF), which assumes a variable kinematic displacement field over the cross-sections of the beam. Two different sets of polynomials that correspond to Taylor (TE) or Lagrange (LE) expansions were used. The analyses focused on three reinforced structures: a stiffened panel, a reinforced cylinder and the complete structure of the launcher. The frequencies and natural modes obtained using one-dimensional models are compared to those obtained from classical finite element analysis. The classical FE models were built using a beam-shell or solid elements, and the results indicate that the refined beam models can in fact be used to investigate the behavior of very complex reinforced structures. These models can predict the shell-like modes that are typical of thin-walled structures that cannot be detected using classical beam models. The refined 1D models used in the present work provide results that are as accurate as those from solid FE models, but the 1D models have a much lower computational cost.

Analysis of Stokes flows by Carrera unified formulation

  • Varello, Alberto;Pagani, Alfonso;Guarnera, Daniele;Carrera, Erasmo
    • Advances in aircraft and spacecraft science
    • /
    • v.5 no.3
    • /
    • pp.363-383
    • /
    • 2018
  • One-dimensional (1D) models of incompressible flows, can be of interest for many applications in which fast resolution times are demanded, such as fluid-structure interaction of flows in compliant pipes and hemodynamics. This work proposes a higher-order 1D theory for the flow-field analysis of incompressible, laminar, and viscous fluids in rigid pipes. This methodology is developed in the domain of the Carrera Unified Formulation (CUF), which was first employed in structural mechanics. In the framework of 1D modelling, CUF allows to express the primary variables (i.e., velocity and pressure fields in the case of incompressible flows) as arbitrary expansions of the generalized unknowns, which are functions of the 1D computational domain coordinate. As a consequence, the governing equations can be expressed in terms of fundamental nuclei, which are invariant of the theory approximation order. Several numerical examples are considered for validating this novel methodology, including simple Poiseuille flows in circular pipes and more complex velocity/pressure profiles of Stokes fluids into non-conventional computational domains. The attention is mainly focused on the use of hierarchical McLaurin polynomials as well as piece-wise nonlocal Lagrange expansions of the generalized unknowns across the pipe section. The preliminary results show the great advantages in terms of computational costs of the proposed method. Furthermore, they provide enough confidence for future extensions to more complex fluid-dynamics problems and fluid-structure interaction analysis.

A Study on the Cuf-off Speed of Small-scale Wind Power System for Battery Charging (배터리 충전을 위한 소형풍력 발전 시스템의 한계 풍속에 관한 연구)

  • Ku, Hyun-Keun;Lee, Hyung-Uk;Kim, Jang-Mok
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.63 no.4
    • /
    • pp.484-489
    • /
    • 2014
  • Three phase PWM(Pulse Width Modulation) converter of the small-scale wind power system is able to charge battery under the rated wind speed regions. However, it is impossible to control output power of converter at the over win speed region because back-EMF(Electro Motive Force) of PMSG(Permanent Magnet Synchronous Generator) is higher than the battery terminal voltage of PMSG is reduced. However, the cut-off wind speed exists although battery charging algorithm is implemented by flux weakening control method. Therefore, this paper performs analysis of other factors which affects limitation wind speed. The validity of the analysis are verified through simulation.

Characteristics Analysis of 3-phase Induction Generator at the Unbalanced Load Operation (불평형 부하 운전시 3상 유도발전기 특성 해석)

  • Kim, Jong-Gyeum
    • The Transactions of the Korean Institute of Electrical Engineers P
    • /
    • v.56 no.3
    • /
    • pp.123-128
    • /
    • 2007
  • Hydro power supplies no pollution energy, mainly induction generator has been applied at the small capacity power station. The generating power of small hydro-electric power station connects on the 22.9kV distribution system or low voltage system in the case of three-phase four-wire supply system. There are side effects of various kinds in the 3-three phase 4-wire distribution system mixing 1-phase load and 3-phase load. This system generates the voltage unbalance by unbalanced load operating condition. They have various serious effects on generator and connection system. In this paper, we analyzed what kind of operation characteristic are happened in the induction generator by customer load variation at the 3-three phase 4-wire distribution system.