Experimental and Theoretical Modeling of Cargo Sloshing During Braking

2016 ◽  
Author(s):  
José Antonio Romero Navarrete ◽  
Frank Otremba
Keyword(s):  
Stopping Time ◽  
Full Scale ◽  
Simplified Model ◽  
Maximum Pressure ◽  
Theoretical Studies ◽  
Simplified Approach ◽  
Sloshing Frequency ◽  
Sloshing Dynamics ◽  
Scale Experiment ◽  
Experimental And Theoretical Studies

Taking into account a multitude of experimental and theoretical studies reported in the literature, the braking efficiency of road tankers can be affected by the sloshing forces developed by the carried liquid during such maneuvers, as a result of the dynamic pressures exerted by the sloshing liquid on the vehicle containers walls, and of the shifting of the liquid center of gravity. However, such studies have not involved a full scale experiment. In this paper, a simplified model is proposed to study the effect of the sloshing dynamics on a road tanker braking efficiency. Results from this simplified approach, are compared with data from full scale testing, revealing that the simplified model is good to predict the maximum pressure that the sloshing liquid exerts on one of the vehicle chambers. The simplified model considers a straight truck and a pendulum analogy for the sloshing liquid, whose parameters are derived from a validated methodology to predict the sloshing frequency of the fluid within its container. Simulation of non-sloshing cargo further suggests that the stopping time can be increased by 7 % due to the sloshing cargo.

Aspects of Host Finding by the Cattle Tick, Boophilus microplus.

1978 ◽  
Vol 26 (1) ◽  
pp. 159 ◽  
Author(s):  
RW Sutherst ◽  
MJ Dallwitz ◽  
KBW Utech ◽  
JD Kerr
Keyword(s):  
Host Finding ◽  
Tick Control ◽  
Boophilus Microplus ◽  
Simplified Model ◽  
Cattle Tick ◽  
Theoretical Studies ◽  
Total Proportion ◽  
Stocking Rates ◽  
Experimental And Theoretical Studies ◽  
Reduced Activity

Experimental and theoretical studies on the rates of host finding by larvae of the cattle tick B. microplus are described. At stocking rates of about two beasts per hectare the cattle picked up between 30 and 70% of the larvae in a week, compared with 50 to 85% with five beasts per hectare. Each beast effectively picked up all the ticks from an area of 0.022-0.075 ha each day. The lower values were associated with lower minimum temperatures, a phenomenon which was attributed to reduced activity of the larvae. A simplified model was developed to investigate the sensitivity of the host-finding component of the tick's life system to the parameters controlling the process. It was found that the total proportion of larvae finding a host could be expressed as a function of the product of the host-finding rate and the median duration of survival of the larvae. Pasture spelling for tick control was also considered in relation to the parameters of the model.

scholarly journals STUDY OF THE PASTE-LIKE PROPELLANT COMBUSTION AT VARIOUS LOADING SCHEMES

2020 ◽  
pp. 89-101
Author(s):  
Viktor V. BURKIN ◽  
◽  
Aleksey S. D’YACHKOVSKIY ◽  
Aleksandr N. ISHCHENKO ◽  
Vladimir Z. KASIMOV ◽  
...  
Keyword(s):  
Maximum Pressure ◽  
Theoretical Studies ◽  
Powder Charge ◽  
Propellant Combustion ◽  
Dispersion Law ◽  
Different Types ◽  
Propellant Charge ◽  
The Mathematical Model ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

The experimental and theoretical studies of the paste-like propellant combustion in a model ballistic installation are implemented. The research is carried out using three masses of projectile assemblies and three types of the propellant charge. The paper presents two versions of the law of dispersion for paste-like propellants which allow accounting for the pressure on the front and acceleration of the projectile assembly with a traveling charge. The coefficients in the laws of dispersion are obtained. Using the mathematical model presented in this work, the gas-dynamic pictures of the shots when the propellants are applied as traveling charges are obtained for each dispersion law. Based on the results, a detailed study of the processes occurring with the traveling charge consisting of a model paste-like propellant is implemented for various shot arrangements. The discrepancy between theoretical results and the results obtained in the set of experiments is no more than 2% for the maximum pressure and no more than 1% for the muzzle velocity. The dispersion law accounting for the projectile assembly acceleration and traveling charge makes it possible to describe accurately the processes in the space behind the projectile for projectile assemblies of various masses and different types of granulated powder charge in terms of the model ballistic installation in the considered pressure range.

The Stabilizing Effect of Pre-Equilibria: A Trifluoromethyl Complex as CF2 Reservoir in Catalytic Olefin Difluorocarbenation

2020 ◽  
Author(s):  
Thomas Louis-Goff ◽  
Huu Vinh Trinh ◽  
Eileen Chen ◽  
Arnold L. Rheingold ◽  
Christian Ehm ◽  
...  
Keyword(s):  
High Selectivity ◽  
Side Reactions ◽  
Theoretical Studies ◽  
Attractive Feature ◽  
Catalyst Recovery ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Experimental And Theoretical Studies

A new, efficient, catalytic difluorocarbenation of olefins to give 1,1-difluorocyclopropanes is presented. The catalyst, an organobismuth complex, uses TMSCF<sub>3</sub> as a stoichiometric difluorocarbene source. We demonstrate both the viability and robustness of this reaction over a wide range of alkenes and alkynes, including electron-poor alkenes, to generate the corresponding 1,1-difluorocyclopropanes and 1,1-difluorocyclopropenes. Ease of catalyst recovery from the reaction mixture is another attractive feature of this method. In depth experimental and theoretical studies showed that the key difluorocarbene-generating step proceeds through a bismuth non-redox synchronous mechanism generating a highly reactive free CF<sub>2</sub> in an endergonic pre-equilibrium. It is the reversibility when generating the difluorocarbene that accounts for the high selectivity, while minimizing CF<sub>2</sub>-recombination side-reactions.

Strong coupling: resonant effects

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Strong Coupling ◽  
Experimental Studies ◽  
Strong Coupling Regime ◽  
Theoretical Studies ◽  
Stimulated Scattering ◽  
Quantum Theories ◽  
Pump Probe ◽  
Exciton Polaritons ◽  
Linear Optical Properties ◽  
Experimental And Theoretical Studies

This chapter presents experimental studies performed on planar semiconductor microcavities in the strong-coupling regime. The first section reviews linear experiments performed in the 1990s that evidence the linear optical properties of cavity exciton-polaritons. The chapter is then focused on experimental and theoretical studies of resonantly excited microcavity emission. We mainly describe experimental configuations in which stimulated scattering was observed due to formation of a dynamical condensate of polaritons. Pump-probe and cw experiments are described in addition. Dressing of the polariton dispersion and bistability of the polariton system due to inter-condensate interactions are discussed. The semiclassical and the quantum theories of these effects are presented and their results analysed. The potential for realization of devices is also discussed.

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