Application of morphed non-linear phase oscillators for representing rolling piston compressor performance

2019 ◽  
Vol 234 (3) ◽  
pp. 332-341
Author(s):  
Balázs Farkas ◽  
Jenö Miklós Suda
Keyword(s):  
Thermal Stresses ◽  
Pressure Fluctuations ◽  
Piston Compressor ◽  
Van Der Pol Oscillator ◽  
Phase Oscillators ◽  
Non Linear ◽  
Complex Models ◽  
Rolling Piston ◽  
Definition Of ◽  
Incremental Learning Method

Rolling piston compressors are small capacity volumetric machines used mainly in household refrigerator and heat-pump units. One of the main characteristics of the compressor is the way how the pressure builds up within the cylinder. This information can be used in more complex models for further investigations, e.g. to analyse the mechanical and thermal stresses of the compressor components. Modelling methods to resemble the pressurisation process of the rolling piston compressor with non-linear oscillators is presented in this paper. The mathematical description of the non-linear oscillators can be used to produce a continuous signal resembling the pressure fluctuations within the cylinder. For the definition of the necessary functions, the main characteristics of the typical rolling piston pressurisation diagram were identified. At first the pressurisation process was approximated by using the mathematical formula of the common Van der Pol oscillator. The oscillator was modified and extended with a linear second order differential equation to improve the resemblance between the target and model functions. To achieve better agreement with the target diagrams, Morphed non-linear oscillators were established. Polynomial and constructive incremental learning method was used to achieve adequate data fitting and the results of both methods were compared. The results show acceptable conformity and proved to be adequate to provide input data for further investigations i.e. for parametric studies of the compressor design. Besides modelling rolling piston compressors, this method can be applied for other volumetric compressors with cyclic pressurization sequence.

scholarly journals Accurate radial basis functions technique for competitive and efficient solutions of non-linear Black-Scholes equations

2020 ◽  
Vol 20 (4) ◽  
pp. 60-83
Author(s):  
Vinícius Magalhães Pinto Marques ◽  
Gisele Tessari Santos ◽  
Mauri Fortes
Keyword(s):  
Radial Basis Function ◽  
Basis Function ◽  
Efficient Solutions ◽  
Basis Functions ◽  
Adaptive Scheme ◽  
Call Options ◽  
Black Scholes ◽  
Non Linear ◽  
Radial Basis ◽  
Complex Models

ABSTRACTObjective: This article aims to solve the non-linear Black Scholes (BS) equation for European call options using Radial Basis Function (RBF) Multi-Quadratic (MQ) Method.Methodology / Approach: This work uses the MQ RBF method applied to the solution of two complex models of nonlinear BS equation for prices of European call options with modified volatility. Linear BS models are also solved to visualize the effects of modified volatility.  Additionally, an adaptive scheme is implemented in time based on the Runge-Kutta-Fehlberg (RKF) method.

The Static Aeroelasticity of Slender Configurations

1963 ◽  
Vol 14 (1) ◽  
pp. 75-104 ◽  
Author(s):  
G. J. Hancock
Keyword(s):  
Static Stability ◽  
Aerodynamic Forces ◽  
Flexible Aircraft ◽  
The Past ◽  
Plate Models ◽  
Non Linear ◽  
The Future ◽  
Static Aeroelasticity ◽  
Definition Of ◽  
Image Position

SummaryThe validity and applicability of the static margin (stick fixed) Kn,where as defined by Gates and Lyon is shown to be restricted to the conventional flexible aircraft. Alternative suggestions for the definition of static margin are put forward which can be equally applied to the conventional flexible aircraft of the past and the integrated flexible aircraft of the future. Calculations have been carried out on simple slender plate models with both linear and non-linear aerodynamic forces to assess their static stability characteristics.

The Metaphor of Hunting and the Method of Division in the Sophist

2018 ◽  
pp. 55-60
Author(s):  
George Bruseker
Keyword(s):  
Iterative Process ◽  
Pedagogical Tool ◽  
Non Linear ◽  
Definition Of

This paper examines the metaphor of hunting as used in Plato’s dialogue, the Sophist. In it, we explore the idea that the example of the ‘angler’ given at the start of the dialogue is no throw-away example, but opens up the metaphor of hunting as an important element of understanding how to use the method of division introduced for coming to definitional knowledge. I argue that the use of the metaphor of hunting is a pedagogical tool that transforms the attentive student’s understanding of the method of division from a dry science of definition, to a manner of approaching the search for truth. Applied reflexively to the search for the definition of the sophist, it helps reveal that the search for knowledge is a non-linear, iterative process which requires passing-through, and abides no shortcuts. It leaves open the suggestion that the true image of knowledge and the philosopher may finally be found in a version of acquisitive rather than productive or seperative arts (as they are classified within the dialogue).

A Simulation Study on Translational Piston Air Compressor

2011 ◽  
Vol 328-330 ◽  
pp. 628-632
Author(s):  
Kui Hua Geng ◽  
Meng Tang ◽  
Hong Dong Yu ◽  
Ai Nong Geng ◽  
Shi Guang Du
Keyword(s):  
Simulation Study ◽  
Relative Velocity ◽  
Friction And Wear ◽  
Kinetic Characteristic ◽  
Translational Motion ◽  
Piston Compressor ◽  
Working Principle ◽  
Rolling Piston ◽  
Rotary Speed ◽  
Conventional Rolling

The structure and working principle of a new translational piston compressor was introduced in this paper. Its piston works in a way of translational motion, hence reduces the piston’s relative velocity to cylinder and cap, as well as friction and wear. In order to avoid vane detaching from piston, simulations were carried out regarding the pre-tightening spring and an optimal preload of the spring was obtained. By analyzed and compared to conventional rolling piston compressor in term of contact force between vane and piston, it was pointed out that the new compressor possessed advantage of kinetic characteristic and is more suitable for the situation of high rotary speed.

Non-Linear Intracranial Dynamics of Shunt Siphoning

2003 ◽  
Author(s):  
Vanessa A. Capanzano ◽  
Jifeng Peng ◽  
Lili Zheng ◽  
Michael Egnor ◽  
Mark Washgul
Keyword(s):  
Cerebrospinal Fluid ◽  
Side Effects ◽  
Linear Model ◽  
Van Der Pol Oscillator ◽  
Van Der Pol ◽  
Non Linear ◽  
Negative Effect

Siphoning is commonly associated with shunts, a treatment used in patients suffering from Hydrocephalus. Siphoning is known to have a negative effect on intracranial dynamics. In this paper, a model will be developed for the intracranial dynamics in the presence of siphoning based on the assumption of pulsatile intracranial dynamics as a forced non-linear van der Pol oscillator. This non-linear model is used to simulate how various degrees of siphoning can effect intracranial dynamics and create an understanding of painful side effects, such as vascular headaches. The model suggests that vascular headaches are due to an increase in the amplitude of arterial pulsations caused by the force exerted on the cranium by siphoning rather than due to volume shifts of cerebrospinal fluid (CSF).

Evaluation of Non-Linear and Linear Mathematical Models for Creatinine and Glucose Fitting in Peritoneal Dialysis

1996 ◽  
Vol 19 (4) ◽  
pp. 221-231
Author(s):  
G. Amici
Keyword(s):  
Peritoneal Dialysis ◽  
Concentration Ratio ◽  
Linear Models ◽  
Linear Transformations ◽  
Peritoneal Equilibration Test ◽  
Peritoneal Transport ◽  
Non Linear ◽  
Definition Of ◽  
The Individual ◽  
Fitting In

Four non-linear and five linear models for predicting the creatinine dialysate/plasma ratio (CRD/P) and the glucose dialysate/initial concentration ratio (GLD/Do) were evaluated in a group of 31 patients on peritoneal dialysis and subjected to the peritoneal equilibration test (PET 3.86%, 240'). PET results and classification were compared to obtain a definition of patient peritoneal transport characteristics. The monomolecular and rectangular hyperbola non-linear models, the Lineweaver-Burk, Hanes-Woolf and Dadone linear transformations were considered for the CRD/P fitting. A monoexponential and two-exponential decay plus the semilogarithmic transformations were considered for the GLD/Do. These models are simple, accurate and functionally homogeneous. Further studies are advisable however on the individual peritoneal transport classification, since ∼30% of the patients were in different categories for CRD/P and GLD/Do and the fittings do not give better classification results.

scholarly journals Simulation Informed CAD for 3D Nanoprinting

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 8 ◽  
Author(s):  
Jason D. Fowlkes ◽  
Robert Winkler ◽  
Eva Mutunga ◽  
Philip D. Rack ◽  
Harald Plank
Keyword(s):  
Analytical Model ◽  
Computer Aided Design ◽  
Critical Mass ◽  
Three Dimensional ◽  
Three Dimensional Objects ◽  
Non Linear ◽  
Out Of Plane ◽  
Digital Scanning ◽  
Definition Of ◽  
Bending Nanowires

A promising 3D nanoprinting method, used to deposit nanoscale mesh style objects, is prone to non-linear distortions which limits the complexity and variety of deposit geometries. The method, focused electron beam-induced deposition (FEBID), uses a nanoscale electron probe for continuous dissociation of surface adsorbed precursor molecules which drives highly localized deposition. Three dimensional objects are deposited using a 2D digital scanning pattern—the digital beam speed controls deposition into the third, or out-of-plane dimension. Multiple computer-aided design (CAD) programs exist for FEBID mesh object definition but rely on the definition of nodes and interconnecting linear nanowires. Thus, a method is needed to prevent non-linear/bending nanowires for accurate geometric synthesis. An analytical model is derived based on simulation results, calibrated using real experiments, to ensure linear nanowire deposition to compensate for implicit beam heating that takes place during FEBID. The model subsequently compensates and informs the exposure file containing the pixel-by-pixel scanning instructions, ensuring nanowire linearity by appropriately adjusting the patterning beam speeds. The derivation of the model is presented, based on a critical mass balance revealed by simulations and the strategy used to integrate the physics-based analytical model into an existing 3D nanoprinting CAD program is overviewed.

Finite Element Simulation of Multilayer Metal Cylinder Head Gaskets

2006 ◽  
Author(s):  
Mario Durando ◽  
Domenico Petronio ◽  
Giuseppe Rivilli ◽  
Gabriele Virzi` Mariotti
Keyword(s):  
Cylinder Head ◽  
Fem Analysis ◽  
Flexible Tool ◽  
Actual Case ◽  
Mesh Topology ◽  
Element Simulation ◽  
Calculation Methodology ◽  
Complex Models ◽  
Definition Of ◽  
Multilayer Metal

The ABAQUS gasket elements are an efficient and flexible tool to study gasket applications. Nevertheless their usage is not limited to gasket analysis, but it provides an effective improvement in structural analysis. The results point out that both the predicted contact pressure and the predicted stress distribution depend on the mesh topology. Several combinations of mesh dimension and topology are investigated. The purpose is the definition of a calculation methodology and the demonstration of the application efficiency. Complex models analysis highlights that the defined methodology represents an effective tool for the design and the optimisation of the head gasket, the cylinder head and the engine block. The methodology is then applied to an actual case. A layout modification to prevent a sealing issue is validated by the FEM analysis. The modification was introduced in the actual component. The qualitative and quantitative evidences provided by the calculation were confirmed by the experimental results obtained by colour films (not running engine with assembly loads at room temperature) and by the test bench (actual working conditions).

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