Musculoskeletal modeling‐based definition of load cases and worst‐case fracture orientation for the design of clavicle fixation plates

2021 ◽  
Author(s):  
Sanne Vancleef ◽  
Mariska Wesseling ◽  
Jos Vander Sloten ◽  
Ilse Jonkers
Keyword(s):  
Musculoskeletal Modeling ◽  
Worst Case ◽  
Fracture Orientation ◽  
Definition Of

A New Type of Gas Turbine Based-Hybrid Propulsion System: Part 1—Concept Development, Definition of Mission Parameters and Preliminary Sizing

2000 ◽  
Author(s):  
Emiliano Cioffarelli ◽  
Enrico Sciubba
Keyword(s):  
Gas Turbine ◽  
Combustion Engine ◽  
Development Program ◽  
Propulsion System ◽  
Medium Size ◽  
Passenger Cars ◽  
Worst Case ◽  
Hybrid Propulsion ◽  
Wide Range ◽  
Definition Of

Abstract A hybrid propulsion system of new conception for medium-size passenger cars is described and its preliminary design developed. The system consists of a turbogas set operating at fixed rpm, and a battery-operated electric motor that constitutes the actual “propulsor”. The battery pack is charged by the thermal engine which works in an electronically controlled on/off mode. Though the idea is not entirely new (there are some concept cars with similar characteristics), the present study has important new aspects, in that it bases the sizing of the thermal engine on the foreseen “worst case” vehicle mission (derived from available data on mileage and consumption derived from road tests and standard EEC driving mission cycles) that they can in fact be accomplished, and then proceeds to develop a control strategy that enables the vehicle to perform at its near–peak efficiency over a wide range of possible missions. To increase the driveability of the car, a variable-inlet vane system is provided for the gas turbine. After developing the mission concept, and showing via a thorough set of energy balances (integrated over various mission profiles), a preliminary sizing of the turbogas set is performed. The results of this first part of the development program show that the concept is indeed feasible, and that it has important advantages over both more traditional (Hybrid Vehicles powered by an Internal Combustion Engine) and novel (All-Electric Vehicle) propulsion systems.

Topology Optimization of Dynamic Systems Under Uncertain Loads: An H∞-Norm-Based Approach

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Paolo Venini
Keyword(s):  
Topology Optimization ◽  
Structural Parameters ◽  
Goal Function ◽  
Dynamic Compliance ◽  
Case Scenario ◽  
Worst Case ◽  
Original Definition ◽  
Optimal Material ◽  
The One ◽  
Definition Of

An innovative approach to topology optimization of dynamic system is introduced that is based on the system transfer-function H∞-norm. As for the structure, the proposed strategy allows to determine the optimal material distribution that ensures the minimization of a suitable goal function, such as (an original definition of) the dynamic compliance. Load uncertainty is accounted for by means of a nonprobabilistic convex-set approach (Ben-Haim and Elishakoff, 1990, Convex Models of Uncertainty in Applied Mechanics, Elsevier Science, Amsterdam). At each iteration, the worst load is determined as the one that maximizes the current dynamic compliance so that the proposed strategy fits the so-called worst case scenario (WCS) approach. The overall approach consists of the repeated solution of the two steps (minimization of the dynamic compliance with respect to structural parameters and maximization of the dynamic compliance with respect to the acting load) until convergence is achieved. Results from representative numerical studies are eventually presented along with extensions to the proposed approach that are currently under development.

The effect of base flow variation on flow stability

2003 ◽  
Vol 476 ◽  
pp. 293-302 ◽  
Author(s):  
ALESSANDRO BOTTARO ◽  
PETER CORBETT ◽  
PAOLO LUCHINI
Keyword(s):  
Hydrodynamic Stability ◽  
Base Flow ◽  
Plane Couette Flow ◽  
Worst Case ◽  
Unconditionally Stable ◽  
Variational Techniques ◽  
Parallel Flows ◽  
The Stability ◽  
Definition Of ◽  
The Ideal

The Orr–Sommerfeld operator's eigenvalues determine the stability of exponentially growing disturbances in parallel and quasi-parallel flows. This work assesses the sensitivity of these eigenvalues to modifications of the base flow, which need not be infinitesimally small. Such base flow variations may represent differences between the laboratory flow and its ideal, theoretical counterpart. The worst case, i.e. the change in base flow with the most destabilizing effect on the eigenvalues, is found using variational techniques for the plane Couette flow. Relatively small changes in the base flow are shown to be destabilizing, although the ideal flow is unconditionally stable according to linear theory. These observations inspire a velocity-based definition of pseudospectra in the hydrodynamic stability context.

scholarly journals THE RELIABILITY OF DETERMINING THE SHORT CIRCUIT ZONE OF THE LINES OF 6–35 kV

2018 ◽  
Vol 61 (1) ◽  
pp. 5-14 ◽  
Author(s):  
F. А. Romaniuk ◽  
E. V. Buloichyk ◽  
O. A. Huryanchyk ◽  
V. S. Kachenya
Keyword(s):  
Fault Zone ◽  
Fault Location ◽  
Dynamic Properties ◽  
Short Circuit ◽  
Correction Method ◽  
Worst Case ◽  
Factors Affecting ◽  
Definition Of ◽  
Major Factors

A method of increasing the reliability of determining the zone of short-circuit at the current step protection of the lines of 6–35 kV with unilateral power, aimed at improvement of their technical perfection, is presented in the paper. Having taken the relative simpleness of the current protection into account the authors consider the unilateral remote method of accounting the parameters of the emergency mode and the type of fault to be the most suitable for the implementation of the algorithm of its functioning as compared with the existing methods of fault location. The major factors affecting the accuracy of determining the short circuit zone based on the remote method are noted. With the use of the method of computational experiment the influence of the load currents and contact resistances of various levels on the magnitude and character of changes of errors of determination of the calculated distance of the point of fault from the protection installation location taking into account the errors of measuring transformers. It is demonstrated that in many cases of arc short circuit in a loaded line in order to define the zone of short-circuit with fair accuracy correction of the estimated distance to the fault as calculated by the parameters of the damaged loop (loops) is required. According to the results of numerical experiments corrective expressions on the basis of two relative asymmetry currents determined by the current values of the differences of the phase currents of the line for detecting a type of a short circuit have been obtained. The assessment of the efficiency of the proposed method has been performed. It is shown that the application of the proposed correction method makes it possible to increase the accuracy of fault zone detection. The dynamic properties of the proposed method applied to different modes of the line functioning have been studied. It is determined that in the worst case the definition of the fault zone for a maximum duration of 26 μsec is provided.

Facilitated group discussion method for prevention sexual harassment

2020 ◽  
Author(s):  
Hanna Vehkamäki ◽  
Anniina Lauri ◽  
Eija Tuominen ◽  
Päivi Salmesvuori
Keyword(s):  
Sexual Harassment ◽  
Large Fraction ◽  
Group Discussion ◽  
Professional Networks ◽  
Worst Case ◽  
Clear Cut ◽  
Qualitative Survey ◽  
Education Community ◽  
Definition Of ◽  
Mixed Gender

<p> #metoo movement has raised discussion on the extent of sexual harassment also in the academia. In 2018 Helsinki Association of Women Researchers (Finland) conducted a qualitative survey on experiences of sexual harassment and opinions on definition of sexual harassment among Finnish universities. The results show that sexual harassment and related power misuse are problems also in the Finnish research and higher education community. While there are clear cut cases that can be immediately recognized as harassment, a large fraction of the cases belong to the grey area, causing hesitation and deficiencies in reporting and actions. This, among personal suffering, also maintains a risk that the borderline behaviour escalates to the next level. Common definitions of sexual harassment include phrases such as ‘unwanted’ or ‘without consent’, which are difficult to interpret unambiguously. Beside provocative statements, there has also been genuine concern that mixed gender workplace social interaction can be interpreted as harassment, which in the worst case can lead to even increased segregation of professional networks based on gender, which is a severe threat to equal opportunities. We have developed and tested a facilitated group discussion activity for workplace communities to establish common understanding for the borders of sexual harassment. The activity involves discussions on hypothetical borderline harassment cases in small groups. The aim is not to form an unequivocal verdict on whether these cases are harassment or not, but discuss which factors affect the assessment. The diversity of opinions rising from, for example, personal and cultural differences is collected on an online-based white-board. We have conducted the activity as part of departmental recreation days and staff training events, and the participants feedback indicates that it is a useful tool in making people more aware of the differences in personal borderlines. Facilitated discussions help in creating an atmosphere where people, irrespective of their position in the power structure, feel more free to express if the limits of their comfort zone have been breached, and where drawing a line is respected rather than ridiculed. The activity not only helps in preventing sexual harassment and bullying, but also stress and burnout by creating a culture where protecting personal limits is permitted and respected.</p>

Financial Market Infrastructures

2016 ◽  
pp. 1-19
Author(s):  
Martin Diehl
Keyword(s):  
Financial Markets ◽  
Financial Market ◽  
Financial System ◽  
Relevant Information ◽  
Payment Systems ◽  
Worst Case ◽  
Analytical Importance ◽  
The Stability ◽  
Definition Of ◽  
Market Infrastructure

Like a human being's backbone, well-functioning financial market infrastructures contribute to the stability of the financial system. They enable fast and smooth movements, channel relevant information, protect the channels for transmission and reduce risk. Problems in financial market infrastructures may lead to dysfunctions of financial markets, a lack of options for transaction and, therefore, to limited movability, misleading information or disturbed information channels and in the worst case to systemic risk. The chapter explains the role of financial market infrastructure within the wider definition of a financial system. Based on the historical emergence of payment systems, central clearing and central securities depositories, the special advantage of financial market infrastructures for the productivity of intermediaries, for the efficiency of financial markets and for the welfare of an economy is explained. The chapter shows the economic and analytical importance and specificity of financial market infrastructures.

Mathematical model to assess the actual environmental risk from the point source emissions

2014 ◽  
Vol 25 (3-4) ◽  
pp. 91-98
Author(s):  
V. N. Poltoratskaya
Keyword(s):  
Mathematical Model ◽  
Air Pollution ◽  
Point Source ◽  
Density Distribution ◽  
Environmental Risk ◽  
Point Sources ◽  
Design Parameters ◽  
Worst Case ◽  
Maximum Admissible Concentration ◽  
Definition Of

A mathematical model for point source emissions, which allows to determine the ecological risk, improve the ecological situation in the region with the ability to manage risk. Environmental risk is defined as the probability of exceeding a multidimensional integral field concentrations of pollutants its Maximum Admissible Concentration (with a small number of measurements) or frequency exceeding the given measured concentrations of pollutants its Maximum Admissible Concentration (with a large number of measurements). Components of air pollution regions, cities, enterprises are individual emission sources, so primarily developing assessment and environmental risk analysis should be performed for individual sources and, above all, to prevent significant risks – for the prognostic assessment of newly constructed or reconstructed enterprises, and for existing facilities – from the measurement data. For a single point source mathematical model includes: – raw data (results undertorch measurement characteristics of pollutants, sanitary protection and residential areas, the design parameters of the source and characteristics of the external environment for the worst-case); – forecast concentrations of pollutants depending on the design parameters of the source and characteristics of an environment for a source with circular and rectangular mouth, hot and cold emissions, extremely dangerous low wind speeds; – depending on the definition of the amendments to the measured concentrations due to the difference of the worst conditions from measurements; – depending on the definition given to the worst conditions of the measured concentrations and their statistical processing in order to obtain: a) the numerical characteristics of the density distribution of the concentration of pollutants emitted (mathematical expectations, standard deviations and correlation coefficients); b) environmental risk α, defined at a relatively small number of trials as a multidimensional probability integral of the density distribution of the concentrations obtained with the numerical characteristics, and a large number of tests - the frequency of the measured concentrations exceeding; c) environmental risks from air pollution αj separate pollutants; d) depending on the definition of the numerical characteristics of the forecast distribution density is not measured (secondary) concentrations of pollutants emitted to address their risks when determining α and αj. It is shown that, in accordance with applicable regulatory requirements must consider the risk of the negative impact of air pollution to humans, the level of which is determined using the values of the maximum one-time maximum allowable concentrations pollutants. Defined by experienced stochastic patterns of distribution of contaminants in the atmosphere. Studied the random variation of concentrations. Theoretically and experimentally substantiated principles of developing a mathematical model to assess the actual risk from ecological point sources of emissions. 

Evaluation of an Equivalent Design Wave Method to Define Lifetime Combined Loading Scenarios for Trimarans

2019 ◽  
Author(s):  
H. C. Seyffert ◽  
A. A. Kana
Keyword(s):  
System Reliability ◽  
Element Model ◽  
Combined Loading ◽  
Worst Case ◽  
Hull Form ◽  
Risk Levels ◽  
Load Combination ◽  
Marine System ◽  
Definition Of ◽  
Structural Compliance

Abstract The evaluation of marine system reliability requires the definition of the most extreme loading that a vessel is expected to experience. To quantify the risk levels associated with a full ship lifetime, some decisions must be made about which vessel scenarios are worth analyzing, i.e. the worst-case vessel scenarios. The problem is further complicated when considering extreme combined loading on a novel hull form such as a trimaran. To evaluate structural compliance with given acceptance criteria many classification societies suggest defining simultaneous load combination cases by an Equivalent Design Wave (EDW) method for use in a finite element model. This paper examines whether the EDW approach defines realistic lifetime combined loading scenarios specifically for a novel hull form like a trimaran.

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