National Repository of Grey Literature 6 records found  Search took 0.01 seconds. 
Optical coherent methods for analysing transient responses in agriculture products
Trnka, Jan ; Stoklasová, Pavla
The paper deals with an application of point-wise and full field interferometry methods as double-channel laser vibrometry and double-pulsed holographic interferometry to analyse transient phenomena in eggs, coconuts, peaches and cheses.
Hodnocení pevnosti ovoce pomocí měření odezvy při impulzivním zatěžování
Dvořáková, Pavla ; Nedomová, Š. ; Severa, L. ; Trnka, Jan ; Buchar, J.
Dynamic resonance frequency based on dynamic frequency response of excited peach was determined by peach physical properties,such as, peach firmness, peach mass, and day of harvesting. Analysis showed that dominant frequency increased with peach firmness increasing, and dominant frequency decreased with increasing of the peach mass.
Lom vaječné skořápky při rázu
Nedomová, Š. ; Trnka, Jan ; Dvořáková, Pavla ; Severa, L. ; Buchar, J.
Hen's eggshell behaviour at the impact on a rigid plate is studied. The critical impact velocity at which eggshell damage starts has been determined. This velocity depends on the egg's shape. LS DYNA 3D finite element code has been used for the evaluation of the stress and strain distribution in the eggshell during its impact. This numerical simulation enables to evaluate the eggshell strength. This strength is independent on the egg shape as well as on the eggshell thickness. It seems that this strength is an intrinsic material parameter.
Zrání sýrů sledované pomocí akustických metod
Severa, L. ; Nedomová, Š. ; Trnka, Jan ; Dvořáková, Pavla ; Buchar, J.
The objective of this study consists in the assessement the suitability of using the acoustic impulse-response technique to evaluate Edam cheese texture and maturity. The acoustic response - history of the surface displacement and the surface velocities were detected by the double-channel laser-vibrometer. The history of the impact force has been also recorded. The non-destructive impact tests could be useful for predicting cheese ripening.
Studium rázově zatěžovaného slepičího vejce experimentálně i numericky
Buchar, J. ; Trnka, Jan ; Dvořáková, Pavla ; Nedomová, Š.
Eggs were excited by the ball impact on the blunt side or the hipe side or the equator,and the response signals were detected by the laser-vibrometers.Relationship between the dominant frequency and the egg properties has been established.The numerical analysis of the egg impact has been performed using LS DYNA 3D finite element code.
Chování vaječné skořápky nedestruktivně rázově zatěžovaných slepičích vajec
Buchar, J. ; Trnka, Jan ; Dvořáková, Pavla ; Nedomová, Š.
In the given paper the main attention is focused on the vibration behaviour of the egg after impact excitation by a steel ball.A dynamic stiffness parameter,kdyn,is introduced wchis is based on a mathematical mass-spring model of the dynamic behaviour of the egg.A finite element model of the static and dynamic eggshell behaviour has been developed in order to understand better the relationships between the two parameters.

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