Understanding System Zeros

1993 ◽  
Vol 21 (4) ◽  
pp. 316-326
Author(s):  
C. R. Knospe ◽  
V. S. Lefante
Keyword(s):  
Structural Dynamics ◽  
Physical Interpretation ◽  
Natural Frequencies ◽  
Transfer Functions ◽  
System A ◽  
Mass Damper ◽  
The Relationship

An intuitive physical interpretation of a transfer function's poles is easily made: the natural frequencies of the system. A similar physical interpretation of a transfer function's zeros can also be made: the natural frequencies of special subsystems. In this paper, such an interpretation is advanced for certain spring-mass-damper systems using a rigorous and intuitive demonstration. This interpretation may serve as a useful paradigm for understanding the relationship between structural dynamics and transfer functions.

scholarly journals Relations Between Safety and Security in Technical Systems

2007 ◽  
Vol 3 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Zbigniew Smalko
Keyword(s):  
Decision Maker ◽  
Machine System ◽  
System A ◽  
The Subject ◽  
Technical Systems ◽  
Machine Control ◽  
The Relationship

Relations Between Safety and Security in Technical Systems The subject of this paper deals with the relationship between safety and security of the man - machine system. In the above system a man can act both as a decision - maker and operator. His desired psychophysical efficiency lies in the undertaking the correct decisions as well as in the skilful machine control and operating.

scholarly journals Robust H∞ Control of STMDs Used in Structural Systems by Hardware in the Loop Simulation Method

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 55
Author(s):  
Huseyin Aggumus ◽  
Rahmi Guclu
Keyword(s):  
Natural Frequencies ◽  
Experimental Studies ◽  
Mr Damper ◽  
Simulation Method ◽  
Control Element ◽  
Structural Systems ◽  
Hardware In The Loop ◽  
Building Model ◽  
Mass Damper ◽  
Set Up

This paper investigated the performance of a semi-active tuned mass damper (STMD) on a multi-degree of freedom (MDOF) building model. A magnetorheological (MR) damper was used as a control element that provided semi-activity in the STMD. The Hardware in the Loop Simulation (HILS) method was applied to mitigate the difficulty and expense of experimental studies, as well as to obtain more realistic results from numerical simulations. In the implementation of this method for the STMD, the MR damper was set up experimentally, other parts of the system were modeled as computer simulations, and studies were carried out by operating these two parts simultaneously. System performance was investigated by excitation with two different acceleration inputs produced from the natural frequencies of the MDOF building. Additionally, a robust H ∞ controller was designed to determine the voltage transmitted to the MR damper. The results showed that the HILS method could be applied successfully to STMDs used in structural systems, and robust H ∞ controls improve system responses with semi-active control applications. Moreover, the control performance of the MR damper develops with an increase in the mass of the STMD.

scholarly journals Evaluation of laparoscopic vs robotic partial nephrectomy using the margin, ischemia and complications score system: a retrospective single center analysis

2015 ◽  
Vol 87 (1) ◽  
pp. 49 ◽  
Author(s):  
Stefano Ricciardulli ◽  
Qiang Ding ◽  
Xu Zhang ◽  
Hongzhao Li ◽  
Yuzhe Tang ◽  
...  
Keyword(s):  
Partial Nephrectomy ◽  
Risk Groups ◽  
Matched Pair ◽  
P Value ◽  
Robotic Partial Nephrectomy ◽  
Score System ◽  
Operative Outcomes ◽  
System A ◽  
Binary Regression Analysis ◽  
The Relationship

Objective: To evaluate differences between Laparoscopic Partial Nephrectomy (LPN) and Robot-Assisted Partial Nephrectomy (RAPN) using the Margin, Ischemia and Complications (MIC) score system and to evaluate factors related with MIC success. Materials and Methods: Single centre retrospective study on 258 LPN and 58 RAPN performed between January 2012 and January 2014. Success was defined when surgical margins was negative, Warm Ischemia Time (WIT) was ≤ 20 minutes and no major complications occurred. Mann-Whitney-U and Pearson χ2 correlation were used to compare LPN and RAPN. A matched pair comparison was also performed. Spearman correlation (Rho) was used to evaluate the relationship between clinical, intra and post-operative and pathological patients characteristics with MIC score. A binary regression analysis was also performed to evaluate independent factors associated with MIC success. Results: The MIC rate in LPN and RAPN was 55% and 65.5% respectively. No differences in clinical, intra and post-operative outcomes between groups were found. Clinical tumor size (p-value: < 0.001; OR: 0.829; 95% CI: 0.697-0.987), PADUA score (p-value: < 0.001; OR: 0.843; 95% CI: 0.740-0.960), PADUA risk groups (intermediate; p-value: < 0.001; OR: 0.416; 95% CI: 0.238- 0.792; high: p-value: < 0.001; OR: 0.356; 95% CI: 0.199- 0.636), WIT (p-value: < 0.001; OR: 0.598; 95% CI: 0.530- 0.675) were independently associated with MIC. eGFR (< 60 vs ≥ 60 ml/min per 1.73 m2: p-value: < 0.001; OR: 3.356; 95% CI: 1.701-6.621) and Fuhrman nuclear grade (p-value: 0.014; OR: 1.798; 95% CI:1.129-2.865) were also independently associated with MIC. Conclusions: MIC score system is a simple and useful tool to report and to compare different surgical approach.

scholarly journals Influence of the flexibility of beams and slabs in static response and dynamic properties

2016 ◽  
Vol 9 (6) ◽  
pp. 842-855 ◽  
Author(s):  
J. R. BUENO ◽  
◽  
D. D. LORIGGIO ◽  
Keyword(s):  
Finite Element Method ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Vibration Modes ◽  
Linear Regime ◽  
Static Response ◽  
The Finite Element Method ◽  
Standard Code ◽  
The Relationship ◽  
Brazilian Standard

Abstract This article examines numerically the flexibility influence of support beams in static response and dynamic properties of a symmetric plate formed by massive slabs of reinforced concrete in elastic linear regime, using the Finite Element Method. In the static response the variation of bending mo-ments and displacements are evaluated, which depend on the relationship between the flexibility of the slab and the beam. The evaluation of dynamic properties is held in undamped free vibration, through which the vibration modes and the values of the natural frequencies is obtained, which are compared with the limits of the Brazilian standard code for design of concrete structures. Results show that the response may show great variation due to the change in the relationship between bending stiffness of the slabs and the beams.

scholarly journals Client's immersed and distanced speech and therapist's interventions in emotion-focused therapy for depression: an intensive analysis of a case study

2016 ◽  
Vol 19 (2) ◽  
Author(s):  
Ana Bela Couto ◽  
Eunice Barbosa ◽  
Sara Silva ◽  
Tiago Bento ◽  
Ana Sofia Teixeira ◽  
...  
Keyword(s):  
Laboratory Studies ◽  
Clinical Change ◽  
Emotion Focused Therapy ◽  
Client Variables ◽  
Observational Measures ◽  
Helping Skills ◽  
System A ◽  
Therapeutic Dialogue ◽  
The Relationship

Previous laboratory studies have explored the importance of participants adopting an immersed or distanced perspective in the analysis of their experiences. These studies concluded that distancing allows analyzing emotions in a healthier way and immersion leads to higher vulnerability. However, in psychotherapy, the relationship between these perspectives and clinical change has been less investigated. The present study aims to contribute to understanding how these variables evolve during psychotherapy and also to explore the therapist’s contributions to this process. This study analyzes a good-outcome case of emotion-focused therapy for depression through two observational measures of psychotherapy process: the measure of immersed and distanced speech – which identifies client’s adoption of an immersed or distanced stance when talking about their problems – and the helping skills system – which identifies therapist’s interventions focused on exploration, insight or action. Results showed a decrease of immersed speech and an increase of distanced speech along the process, with a higher frequency of exploration skills preceding both types of client’s speech. Finally, the evolution of therapist’s and client’s speech showed a reasonable flexibility of therapeutic dialogue throughout the sessions, in particular due to the evolution of client variables (evidencing a higher diversity of behaviors).

scholarly journals Improvement of Snowgauge Collection Efficiency through a knowledge of solid precipitation fallspeed

2021 ◽  
Author(s):  
Nicolas R. Leroux ◽  
Julie M. Thériault ◽  
Roy Rasmussen
Keyword(s):  
Wind Speed ◽  
Transfer Function ◽  
Transfer Functions ◽  
Collection Efficiency ◽  
Particle Diameter ◽  
Field Site ◽  
Solid Precipitation ◽  
Gauge Data ◽  
The Relationship ◽  
Measured Particle

AbstractThe collection efficiency (CE) of a typical gauge-shield configuration decreases with increasing wind speed, with a high scatter for a given wind speed. The scatter in the CE for a given wind speed arises in part from the variability in the characteristics of falling snow and atmospheric turbulence. This study uses weighing gauge data collected at the Marshall Field Site near Boulder, Colorado during the WMO Solid Precipitation InterComparison Experiment (SPICE) to show that the scatter in the collection efficiency can be reduced by considering the fallspeed of solid precipitation particle types. Particle diameter and fallspeed data from a laser disdrometer were used to arrive at this conclusion. In particular, the scatter in the CE of an unshielded snow gauge and a single Alter shield snow gauge is shown to be largely produced by the variation in measured particle fallspeed. The CE was divided into two classes depending on the measured mean-event particle fallspeed. Slower-falling particles were associated with a lower CE. A new transfer function (i.e. the relationship between CE and other meteorological variables, such as wind speed or air temperature) that includes the fallspeed of the hydrometeors was developed. The RMSE of the adjusted precipitation with respect to a weighing gauge placed in a Double Fence Intercomparison Reference was lower than using previously developed transfer functions. This shows that the measured fallspeed of solid precipitation with a laser disdrometer accounts for a large amount of the observed scatter in weighing gauge collection efficiency.

scholarly journals European Constitutions as sources of Party Law and the Fundamental Law of Hungary = Las Constituciones europeas como fuentes de la Ley de Partidos y la Ley Fundamental de Hungría

2017 ◽  
pp. 51
Author(s):  
Peter Smuk
Keyword(s):  
Political Parties ◽  
Representative Democracy ◽  
Political Regime ◽  
System A ◽  
Constitutional State ◽  
El Sistema ◽  
Election System ◽  
Fundamental Law ◽  
Sociedad Civil ◽  
The Relationship

<p>La regulación de los partidos políticos parece un tema ligeramente descuidado en la literatura constitucional húngara. Así, a pesar de que hay un gran número de cuestiones que deben analizarse y entenderse en los ámbitos de la democracia representativa, en el sistema electoral y en la financiación de los partidos, derivadas de las particularidades del cambio del régimen político, y que hace necesaria la interpretación de nuestro sistema político actual. Un análisis sustantivo de estas cuestiones en términos de derecho constitucional (y desde las ciencias políticas) podría contribuir a una mejor comprensión de la democracia representativa húngara, el estado constitucional, así como la relación entre la sociedad civil y el Estado. En este documento voy a ofrecer una visión general de las normas constitucionales relativas a los partidos políticos europeos y comparar la redacción de la Ley Fundamental de Hungría con las normas constitucionales creadas en 1989.</p><p>The regulation of political parties seems a slightly neglected topic in the Hungarian constitutional literature. It is so despite the fact that there are a large number of questions to be analysed and understood in the fields of representative democracy, election system and party financing arising from the particularities of the change of the political regime, the recent constitution-making or the necessary interpretation of our current political system. A substantive analysis of these questions in terms of constitutional law (and political science) could contribute to a better understanding of the Hungarian representative democracy, constitutional state as well as the relationship between civil society and the state. In this paper I will provide a rough overview of constitutional rules relating to European political parties and compare the wording of the Fundamental Law of Hungary with the constitutional rules created in 1989.</p><div> </div>

scholarly journals Non-Invasive Parameter Identification in Rotordynamics via Fluid Film Bearings: Linking Active Lubrication and Operational Modal Analysis

2016 ◽  
Author(s):  
Ilmar Ferreira Santos ◽  
Peter Kjær Svendsen
Keyword(s):  
Parameter Identification ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Transfer Functions ◽  
Injection Pressure ◽  
Operational Modal Analysis ◽  
Fluid Film ◽  
Non Invasive ◽  
Fluid Film Bearings

In recent years, theoretical and experimental efforts have transformed the conventional tilting-pad journal bearing (TPJB) into a smart mechatronic machine element. The application of electromechanical elements into rotating systems makes feasible the generation of controllable forces over the rotor as a function of a suitable control signal. The servovalve input signal and the radial injection pressure are the two main parameters responsible for dynamically modifying the journal oil film pressure and generating active fluid film forces in controllable fluid film bearings. Such fluid film forces, resulting from a strong coupling between hydrodynamic, hydrostatic and controllable lubrication regimes, can be used either to control or to excite rotor lateral vibrations. If non-invasive forces are generated via lubricant fluid film, in situ parameter identification can be carried out, enabling evaluation of the mechanical condition of the rotating machine. Using the lubricant fluid film as a non-invasive calibrated shaker is troublesome, once several transfer functions among mechanical, hydraulic and electronic components become necessary. In this framework the main original contribution of this paper is to show experimentally that the knowledge about the several transfer functions can be bypassed by using output-only identification techniques. The manuscript links controllable (active) lubrication techniques with operational modal analysis, allowing for in-situ parameter identification in rotordynamics, i.e. estimation of damping ratio and natural frequencies. The experimental analysis is carried out on a rigid rotor-level system supported by one single pair of pads. The estimation of damping and natural frequencies is performed using classical experimental modal analysis (EMA) and operational modal analysis (OMA). Very good agreements between the two experimental approaches are found. Maximum values of the main input parameters, namely servovalve voltage and radial injection pressure, are experimentally found with the objective of defining ranges of non-invasive perturbation forces.

scholarly journals Modal and Vibration Analysis of Filter System in Petrochemical Plant

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Zhongchi Liu ◽  
Ji Wang ◽  
Wie Min Gho ◽  
Xiao Liu ◽  
Xuebing Yu
Keyword(s):  
Structural Integrity ◽  
Natural Frequencies ◽  
Resonance Effect ◽  
Petrochemical Plant ◽  
Structural Fatigue ◽  
Filter System ◽  
Vibration Data ◽  
Finite Element Software ◽  
Vibration Problem ◽  
System A

Filter systems are widely used in petrochemical plants for removing solid impurities from hydrocarbon oils. The backwash is the cleaning process used to remove the impurities on the sieves of the filters without a need to interrupt the operation of the entire system. This paper presents a case study based on the actual project of a filter system in a petrochemical plant, to demonstrate the significant effect of vibration on the structural integrity of piping. The induced vibration had led to the structural fatigue failure of the pipes connecting the filter system. A preliminary assessment suggested that the vibrations are caused by the operation of backwashing of the filter system. A process for solving the vibration problem based on the modal analysis of the filter system using the commercial finite element software for simulation is therefore proposed. The computed natural frequencies of the system and the vibration data measured on site are assessed based on the resonance effect of the complete system including the piping connected to the filters. Several approaches are proposed to adjust the natural frequencies of the system in such a way that an optimal and a reasonable solution for solving the vibration problem is obtained.

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