• 제목/요약/키워드: differential response

검색결과 935건 처리시간 0.03초

Determination of Ag(Ⅰ) Ion at a Modified Carbon Paste Electrode Containing N,N'-Diphenyl Oxamide

  • Won, Mi-Sook;Yeom, Jeong-Sik;Yoon, Jang-Hee;Jeong, Euh-Duck;Shim, Yoon-Bo
    • Bulletin of the Korean Chemical Society
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    • 제24권7호
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    • pp.948-952
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    • 2003
  • New approach for the determination of Ag(I) ion was performed by using a carbon paste electrode (CPE) containing N,N'-Diphenyl oxamide (DPO) with anodic stripping voltammetry. The CMEs have been prepared by making carbon paste mixtures containing an appropriate amount of DPO salt coated onto graphite particles to analyze trace metal ions via complexation followed by stripping voltammetry. Various experimental parameters affecting the response, such as pH, deposition time, temperature, and electrode composition, were carefully optimized. Using differential pulse anodic stripping voltammetry, the logarithmic linear response range for the Ag(I) ion was 1.0 × $10^{-7}$ - 5.0 × $10^{-9}$ M at the deposition time of 10 min, with the detection limit was 7.0 × $10^{-10}$ M. The detection limit adopted from anodic stripping differential pulse voltammetry was 7.0 × $10^{-10}$ M for silver and the relative standard deviation was ± 3.2% at a 5.0 × $10^{-8}$ M of Ag(I) ion (n = 7). The proposed electrode shows a very good selectivity for Ag(I) in a standard solution containing several metals at optimized conditions.

Evolutionary computational approaches for data-driven modeling of multi-dimensional memory-dependent systems

  • Bolourchi, Ali;Masri, Sami F.
    • Smart Structures and Systems
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    • 제15권3호
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    • pp.897-911
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    • 2015
  • This study presents a novel approach based on advancements in Evolutionary Computation for data-driven modeling of complex multi-dimensional memory-dependent systems. The investigated example is a benchmark coupled three-dimensional system that incorporates 6 Bouc-Wen elements, and is subjected to external excitations at three points. The proposed technique of this research adapts Genetic Programming for discovering the optimum structure of the differential equation of an auxiliary variable associated with every specific degree-of-freedom of this system that integrates the imposed effect of vibrations at all other degrees-of-freedom. After the termination of the first phase of the optimization process, a system of differential equations is formed that represent the multi-dimensional hysteretic system. Then, the parameters of this system of differential equations are optimized in the second phase using Genetic Algorithms to yield accurate response estimates globally, because the separately obtained differential equations are coupled essentially, and their true performance can be assessed only when the entire system of coupled differential equations is solved. The resultant model after the second phase of optimization is a low-order low-complexity surrogate computational model that represents the investigated three-dimensional memory-dependent system. Hence, this research presents a promising data-driven modeling technique for obtaining optimized representative models for multi-dimensional hysteretic systems that yield reasonably accurate results, and can be generalized to many problems, in various fields, ranging from engineering to economics as well as biology.

The impact of caudally administrated tramadol on immune response and analgesic efficacy for pediatric patients: a comparative randomized clinical trial

  • Sayed, Jehan Ahmed;Elshafy, Sayed Kaoud Abd;Kamel, Emad Zareif;Riad, Mohamed Amir Fathy;Mahmoud, Amal Ahmed;Khalaf, Ghada Shalaby
    • The Korean Journal of Pain
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    • 제31권3호
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    • pp.206-214
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    • 2018
  • Background: Immune responses appear to be affected by anesthetics and analgesics. We investigated the effects of caudal tramadol on the postoperative immune response and pain management in pediatric patients. Methods: Sixty ASA-I pediatric patients aged 3-10 years undergoing lower abdominal surgery. Patients were randomly assigned either to a caudal bupivacaine (0.25%) group (group B), or a group that received caudal tramadol (1 mg/kg) added to the bupivacaine (0.25%) (group T). Both were diluted in a 0.9% NaCl solution to a total volume of 1ml/ kg. The systemic immune response was measured by collecting blood samples preoperatively, at the end of anesthesia, and at 24 and 72 hours postoperatively, and studied for interleukin IL-6, C-reactive proteins (CRP) cortisol levels, and leucocytes with its differential count. Postoperative pain was assessed along with sedation scales. Results: Postoperative production of IL-6 was significantly higher in group B at the end of anesthesia, than at the $24^{th}$ hour, and at the $72^{nd}$ hour in group B and group T, respectively. The immune response showed leukocytosis with increased percentages of neutrophil and monocytes, and a decreased lymphocyte response rate within both groups with no significant differences between the groups. Cortisol and CRP were significantly higher in group B. Conclusions: Adding tramadol to a caudal bupivacaine block can attenuate the pro-inflammatory cytokine response, Cortisol, and CRP in children undergoing lower abdominal surgery.

The effect of nanoparticle in reduction of critical fluid velocity in pipes conveying fluid

  • Ghaitani, M.M.;Majidian, A.;Shokri, V.
    • Advances in concrete construction
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    • 제9권1호
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    • pp.103-113
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    • 2020
  • This paper deal with the critical fluid velocity response of nanocomposite pipe conveying fluid based on numerical method. The pressure of fluid is obtained based on perturbation method. The motion equations are derived based on classical shell theory, energy method and Hamilton's principle. The shell is reinforced by nanoparticles and the distribution of them are functionally graded (FG). The mixture rule is applied for obtaining the equivalent material properties of the structure. Differential quadrature method (DQM) is utilized for solution of the motion equations in order to obtain the critical fluid velocity. The effects of different parameters such asCNT nanoparticles volume percent, boundary conditions, thickness to radius ratios, length to radius ratios and internal fluid are presented on the critical fluid velocity response structure. The results show that with increasing the CNT nanoparticles, the critical fluid velocity is increased. In addition, FGX distribution of nanoparticles is the best choice for reinforcement.

Fuzzy analysis for stability of steel frame with fixity factor modeled as triangular fuzzy number

  • Tran, Thanh Viet;Vu, Quoc Anh;Le, Xuan Huynh
    • Advances in Computational Design
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    • 제2권1호
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    • pp.29-42
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    • 2017
  • This study presents algorithms for determining the fuzzy critical loads of planar steel frame structures with fixity factors of beam - column and column - base connections are modeled as triangular fuzzy numbers. The finite element method with linear elastic semi-rigid connection and Response Surface Method (RSM) in mathematical statistic are applied for problems with symmetric triangular fuzzy numbers. The ${\alpha}$ - level optimization using the Differential Evolution (DE) involving integrated finite element modeling is proposed to apply for problems with any triangular fuzzy numbers. The advantage of the proposed methodologies is demonstrated through some example problems relating to for the twenty - story, four - bay planar steel frames.

불규칙 지반 가진력을 받는 탄성진자계의 비선형진동응답 (Nonlinear Vibration Responses of a Spring-Pendulum System under Random Base Excitation)

  • 조덕상
    • 한국정밀공학회지
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    • 제18권3호
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    • pp.175-181
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    • 2001
  • An investigation into the response statistics of a spring-pendulum system whose base oscillates randomly along vertical and horizontal line is made. The spring-pendulum system with internal resonance examined is known to be a good model for a variety of engineering systems, including ship motions with nonlinear coupling between pitching and rolling motions. The Fokker-Planck equation is used to generate a general first-order differential equations for the random responses of the system are reduced to a system of autonomous ordinary differential equations. In view of equilibrium solutions of this system and their stability, the response statistics is examined. It is seen that increase in horizontal excitation level leads to a decreased width of the internal resonance region.

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Application of the Equivalent Frequency Response Method to Runoff Analysis

  • Fujita, Mutsuhiro;Hamouda, Ruai;Tanaka, Gaku
    • 한국수자원학회논문집
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    • 제33권S1호
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    • pp.101-110
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    • 2000
  • This paper introduces the equivalent frequency response method(EFRM) into runoff analysis. This EFRM originally had been developed to analyze dynamic behavior of nonlinear elements such as threshold and saturation in control engineering. Many runoff models are described by nonlinear ordinary of partial differential equations This paper presents that these nonlinear differential equations can be converted into semi-linear ones based on EFRM. The word of "a semi-linear equation" means that the coefficients of derived equations depend on average rainfall.

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Nafion-DTPA-Glycerol이 수식된 유리탄소전극을 사용한 미분펄스 전압전류법에 의한 구리(II)이온의 측정 (Differential Pulse Voltammetric Determination of Copper(II) Using Glassy Carbon Electrodes Modified with Nafion-DTPA-Glycerol)

  • 박찬주;박은희;정근호
    • 한국환경보건학회지
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    • 제30권2호
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    • pp.115-122
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    • 2004
  • A glassy carbon electrode(GCE) modified with nafion-DTPA (diethylene triamine-pentaacetic acid)-glycerol is used for the highly selective and sensitive determination of a trace amount of Cu(II). Various experimental parameters, which influenced the response of nafion-DTPA-glycerol modified electrode to Cu(II), are optimized. The Copper(II) is accumulated on the electrode surface by the formation of the complex in an open circuit, and the resulting surface is characterized by medium exchange, electrochemical reduction, and differential pulse voltammetry(DPV). The electrochemical response is evaluated with respect to concentration of modifier, pH and preconcentration time, quiet time, copper(II) concentration, and other variables. A linear range is obtained in the concentration range 1.0${\times}$10$^{-8}$ M-1.0${\times}$10$^{-6}$ MCu(II) with 7 min preconcentration time. The detection limit(3s) is as low as 2.36${\times}$10$^{-8}$ M (1.50 ppb).

Study for the Safety of Ships' Nonlinear Rolling Motion in Beam Seas

  • Long, Zhan-Jun;Lee, Seung-Keon;Jeong, Jae-Hun;Lee, Sung-Jong
    • 한국항해항만학회지
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    • 제33권9호
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    • pp.629-634
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    • 2009
  • Vessels stability problems need to resolve the nonlinear mathematical models of rolling motion. For nonlinear systems subjected to random excitations, there are very few special cases can obtain the exact solutions. In this paper, the specific differential equations of rolling motion for intact ship considering the restoring and damping moment have researched firstly. Then the partial stochastic linearization method is applied to study the response statistics of nonlinear ship rolling motion in beam seas. The ship rolling nonlinear stochastic differential equation is then solved approximately by keeping the equivalent damping coefficient as a parameter and nonlinear response of the ship is determined in the frequency domain by a linear analysis method finally.

Dynamic response of thin plates on time-varying elastic point supports

  • Foyouzat, Mohammad A.;Estekanchi, Homayoon E.
    • Structural Engineering and Mechanics
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    • 제62권4호
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    • pp.431-441
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    • 2017
  • In this article, an analytical-numerical approach is presented in order to determine the dynamic response of thin plates resting on multiple elastic point supports with time-varying stiffness. The proposed method is essentially based on transforming a familiar governing partial differential equation into a new solvable system of linear ordinary differential equations. When dealing with time-invariant stiffness, the solution of this system of equations leads to a symmetric matrix, whose eigenvalues determine the natural frequencies of the point-supported plate. Moreover, this method proves to be applicable for any plate configuration with any type of boundary condition. The results, where possible, are verified upon comparison with available values in the literature, and excellent agreement is achieved.