Experimental Analysis of a Planar Reconfigurable Mechanism With a Variable Joint

2016 ◽  
Author(s):  
Peter W. Malak ◽  
Anthony J. Buchta ◽  
Philip A. Voglewede
Keyword(s):  
Optimal Control ◽  
Transition Point ◽  
Physical Mechanism ◽  
Equations Of Motion ◽  
Angular Position ◽  
The Other ◽  
Simplified Model ◽  
Physical Prototype ◽  
Kinetics Of ◽  
Kinematics And Kinetics

Previously a specific planar reconfigurable mechanism with a variable joint (RRRR1 -RRRP2 Mechanism) was dynamically modeled. The RRRR-RRRP Mechanism functions as a RRRR mechanism in one configuration and as a in RRRP mechanism the other. The kinematics and kinetics of the RRRP and RRRR configurations were previously analyzed with a Lagrangian approach. The developed equations of motion will be validated with a physical prototype in this paper. In addition, a simplified model of the RRRR-RRRP Mechanism is also developed and compared to the experimental results. The experimental angular position of each joint on the RRRR-RRRP Mechanism will be compared to the model position analysis. Particular attention will be given to the transition point when the physical mechanism changes from an RRRR mechanism to RRRP mechanism and vice versa as it is vital to knowing this point for optimal control of the mechanism.

On the Kinematics and Kinetics of Mechanical Seals, Rotors, and Wobbling Bodies

2005 ◽  
Author(s):  
Itzhak Green
Keyword(s):  
Equations Of Motion ◽  
Mechanical Seals ◽  
Kinematical Constraint ◽  
Lagrange’S Equations ◽  
Dynamic Analyses ◽  
Kinematical Model ◽  
Kinetics Of ◽  
Kinematics And Kinetics ◽  
Lagrange's Equations

Mechanical seals, rotors, and wobbling bodies are characterized by a kinematical constraint that prevents them from having integral motion with respect to their own frame. A valid kinematical model is a prerequisite to subsequent dynamic analyses. Three previous works have suggested distinctly different kinematical models to the same problem. The analysis herein presents yet another kinematical model that preserves (actually enforces) the proper kinematical constraint. The outcome reaffirms one of the previous models. The equations of motion are derived using Lagrange’s equations to complement results obtained previously by Newton-Euler mechanics.

Dynamic Analysis of a Planar Mechanism With Variable Topology

2015 ◽  
Author(s):  
Peter W. Malak ◽  
Philip A. Voglewede
Keyword(s):  
Dynamic Analysis ◽  
Lagrangian Approach ◽  
The Other ◽  
Planar Mechanism ◽  
Multiple Tasks ◽  
Variable Topology ◽  
Kinetics Of ◽  
Kinematics And Kinetics

There is a demand for mechanisms with variable topology (MVTs) that can perform multiple tasks with the least amount of actuators. These devices have the ability to provide numerous motion profiles within one device. In this paper, a specific planar MVT was dynamically analyzed. This mechanism functions as a RRRP mechanism (i.e., slider-crank) in one configuration and as a RRRR mechanism (i.e., crank-crank) in the other. The kinematics and kinetics of the RRRP and RRRR configurations were analyzed with a Lagrangian approach. The resulting equations were coded both in equation form and in Matlab SimMechanics then compared. A method for transitioning between configurations was also developed. These equations could be used to develop an applicable controller and principles for synthesizing future MVTs.

The Reactivity of Different Active Forms of Sodium Carbonate with Respect to Sulfur Dioxide

1992 ◽  
Vol 57 (11) ◽  
pp. 2302-2308
Author(s):  
Karel Mocek ◽  
Erich Lippert ◽  
Emerich Erdös
Keyword(s):  
Thermal Decomposition ◽  
Liquid Phase ◽  
Sulfur Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Sodium Carbonate ◽  
Room Temperature ◽  
Active Form ◽  
The Other ◽  
Kinetics Of

The kinetics of the reaction of solid sodium carbonate with sulfur dioxide depends on the microstructure of the solid, which in turn is affected by the way and conditions of its preparation. The active form, analogous to that obtained by thermal decomposition of NaHCO3, emerges from the dehydration of Na2CO3 . 10 H2O in a vacuum or its weathering in air at room temperature. The two active forms are porous and have approximately the same specific surface area. Partial hydration of the active Na2CO3 in air at room temperature followed by thermal dehydration does not bring about a significant decrease in reactivity. On the other hand, if the preparation of anhydrous Na2CO3 involves, partly or completely, the liquid phase, the reactivity of the product is substantially lower.

On the kinetics of Hadamard-type fractional differential systems

2020 ◽  
Vol 23 (2) ◽  
pp. 553-570 ◽  
Author(s):  
Li Ma
Keyword(s):  
Differential Operator ◽  
Numerical Simulations ◽  
Type Inequality ◽  
The Other ◽  
Differential Systems ◽  
Fractional Differential Systems ◽  
Fractional Differential Operator ◽  
Fractional Differential ◽  
Kinetics Of ◽  
Theoretical Results

AbstractThis paper is devoted to the investigation of the kinetics of Hadamard-type fractional differential systems (HTFDSs) in two aspects. On one hand, the nonexistence of non-trivial periodic solutions for general HTFDSs, which are considered in some functional spaces, is proved and the corresponding eigenfunction of Hadamard-type fractional differential operator is also discussed. On the other hand, by the generalized Gronwall-type inequality, we estimate the bound of the Lyapunov exponents for HTFDSs. In addition, numerical simulations are addressed to verify the obtained theoretical results.

scholarly journals Kinematics and kinetics of the bench-press and bench-pull exercises in a strength-trained sporting population

2009 ◽  
Vol 8 (3) ◽  
pp. 245-254 ◽  
Author(s):  
Simon N. Pearson ◽  
John B. Cronin ◽  
Patria A. Hume ◽  
David Slyfield
Keyword(s):  
Bench Press ◽  
Kinetics Of ◽  
Kinematics And Kinetics

Concise Equations for Rotor Dynamics Analysis

1995 ◽  
Author(s):  
W. J. Chen
Keyword(s):  
Equations Of Motion ◽  
Rotor Dynamics ◽  
Memory Storage ◽  
The Other ◽  
Dynamics Analysis ◽  
Real Domain ◽  
The Matrix ◽  
System Equations ◽  
Ordering Algorithms ◽  
Matrix Bandwidth

Abstract Concise equations for rotor dynamics analysis are presented. Two coordinate ordering methods are introduced in the element equations of motion. One is in the real domain and the other is in the complex domain. The two proposed ordering algorithms lead to more compact element matrices. A station numbering technique is also proposed for the system equations during the assembly process. This numbering technique can minimize the matrix bandwidth, the memory storage and can increase the computational efficiency.

scholarly journals Characterization of the Two Mycobacterium tuberculosis recA Promoters

2003 ◽  
Vol 185 (20) ◽  
pp. 6005-6015 ◽  
Author(s):  
Krishna K. Gopaul ◽  
Patricia C. Brooks ◽  
Jean-François Prost ◽  
Elaine O. Davis
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Mycobacterium Tuberculosis ◽  
Promoter Activity ◽  
The Other ◽  
Expression Level ◽  
Promoter Elements ◽  
Kinetics Of

ABSTRACT The recA gene of Mycobacterium tuberculosis is unusual in that it is expressed from two promoters, one of which, P1, is DNA damage inducible independently of LexA and RecA, while the other, P2, is regulated by LexA in the classical way (E. O. Davis, B. Springer, K. K. Gopaul, K. G. Papavinasasundaram, P. Sander, and E. C. Böttger, Mol. Microbiol. 46:791-800, 2002). In this study we characterized these two promoters in more detail. Firstly, we localized the promoter elements for each of the promoters, and in so doing we identified a mutation in each promoter which eliminates promoter activity. Interestingly, a motif with similarity to Escherichia coli σ70 −35 elements but located much closer to the −10 element is important for optimal expression of P1, whereas the sequence at the −35 location is not. Secondly, we found that the sequences flanking the promoters can have a profound effect on the expression level directed by each of the promoters. Finally, we examined the contribution of each of the promoters to recA expression and compared their kinetics of induction following DNA damage.

scholarly journals Charging and coagulation of radioactive and nonradioactive particles in the atmosphere

2015 ◽  
Vol 15 (17) ◽  
pp. 23795-23840
Author(s):  
Y.-H. Kim ◽  
S. Yiacoumi ◽  
A. Nenes ◽  
C. Tsouris
Keyword(s):  
Atmospheric Particles ◽  
The Other ◽  
Urban Atmosphere ◽  
Balance Model ◽  
Charge Accumulation ◽  
Charge Balance ◽  
Charge Distributions ◽  
Coagulation Kinetics ◽  
Balance Charge ◽  
Kinetics Of

Abstract. Charging and coagulation influence one another and impact the particle charge and size distributions in the atmosphere. However, few investigations to date have focused on the coagulation kinetics of atmospheric particles accumulating charge. This study presents three approaches to include mutual effects of charging and coagulation on the microphysical evolution of atmospheric particles such as radioactive particles. The first approach employs ion balance, charge balance, and a bivariate population balance model (PBM) to comprehensively calculate both charge accumulation and coagulation rates of particles. The second approach involves a much simpler description of charging, and uses a monovariate PBM and subsequent effects of charge on particle coagulation. The third approach is further simplified assuming that particles instantaneously reach their steady-state charge distributions. It is found that compared to the other two approaches, the first approach can accurately predict time-dependent changes in the size and charge distributions of particles over a wide size range covering from the free molecule to continuum regimes. The other two approaches can reliably predict both charge accumulation and coagulation rates for particles larger than about 40 nm and atmospherically relevant conditions. These approaches are applied to investigate coagulation kinetics of particles accumulating charge in a radioactive neutralizer, the urban atmosphere, and a radioactive plume. Limitations of the approaches are discussed.

scholarly journals Physical Properties and Non-Isothermal Crystallisation Kinetics of Primary Mechanically Recycled Poly(l-lactic acid) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3396
Author(s):  
Luboš Běhálek ◽  
Jan Novák ◽  
Pavel Brdlík ◽  
Martin Borůvka ◽  
Jiří Habr ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Physical Properties ◽  
Structural Changes ◽  
The Other ◽  
Half Time ◽  
Crystallisation Kinetics ◽  
Isothermal Crystallisation ◽  
Melt Crystallisation ◽  
Kinetics Of ◽  
Crystallisation Rate

The physical properties and non-isothermal melt- and cold-crystallisation kinetics of poly (l-lactic acid) (PLLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biobased polymers reprocessed by mechanical milling of moulded specimens and followed injection moulding with up to seven recycling cycles are investigated. Non-isothermal crystallisation kinetics are evaluated by the half-time of crystallisation and a procedure based on the mathematical treatment of DSC cumulative crystallisation curves at their inflection point (Kratochvil-Kelnar method). Thermomechanical recycling of PLLA raised structural changes that resulted in an increase in melt flow properties by up to six times, a decrease in the thermal stability by up to 80 °C, a reduction in the melt half-time crystallisation by up to about 40%, an increase in the melt crystallisation start temperature, and an increase in the maximum melt crystallisation rate (up to 2.7 times). Furthermore, reprocessing after the first recycling cycle caused the elimination of cold crystallisation when cooling at a slow rate. These structural changes also lowered the cold crystallisation temperature without impacting the maximum cold crystallisation rate. The structural changes of reprocessed PHBV had no significant effect on the non-isothermal crystallisation kinetics of this material. Additionally, the thermomechanical behaviour of reprocessed PHBV indicates that the technological waste of this biopolymer is suitable for recycling as a reusable additive to the virgin polymer matrix. In the case of reprocessed PLLA, on the other hand, a significant decrease in tensile and flexural strength (by 22% and 46%, respectively) was detected, which reflected changes within the biobased polymer structure. Apart from the elastic modulus, all the other thermomechanical properties of PLLA dropped down with an increasing level of recycling.

Sign in / Sign up

Export Citation Format

Share Document