Mathematical Modelling of the Fruit-Stone Culture Seeds Calibration Process Using Flat Sieves

The paper provided describes a mathematical model of calibration process of fruit-stone culture seeds of cherry, sweet cherry, cherry-plum, apricot and almond using flat sieves with impact shock ball cleaners oscillating in the horizontal plane. It has been defined that the mathematical expectation of time of knocking out the fruit-stone from the sieve opening T ⌢ \mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over T} is the minimum value of ratio of average time of complete ball motion cycle in space under sieve to the probability of knocking out the stone by a ball with the kinetic energy level of 2 Mj. The dependences of energy distribution density of ball on impact on the sieve have been obtained, based on which the intervals of ball cleaner parameters have been determined, i.e. the ball diameter D belongs to the interval 25–35 mm; the space height H under sorting sieve belongs to the interval 1.2D–1.4D mm; the value range for distance between rods t belongs to the interval 0.5D–0.7D mm. Using the method of golden section, the following parameters of ball cleaner were obtained: D = 33 mm, t = 23 mm, H = 40 mm. The parameters obtained provide mathematical expectation of time of knocking out the fruit-stone from the sieve opening T ⌢ \mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over T} = 0.03 s. Consequently, the average ball velocity v ⌢ \mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over v} is = 0.4 m∙s-1, and the average ball path is L ⌢ \mathord{\buildrel{\lower3pt\hbox{$\scriptscriptstyle\frown$}}\over L} = 0.006 m.

Changes in the Aromatic Compounds Content in the Muscat Wines as a Result of the Application of Ultrasound during Pre-Fermentative Maceration

This research focuses on the aromatic composition of Muscat of Alexandria wines after the application of ultrasound for 40 or 80 min during a 4 h pre-fermentative maceration process. Two methods of ultrasound application were compared in this study: probe ultrasound and bath ultrasound, for periods of 10–20 min per hour. Increases of more than 200% were obtained for some of the compounds from the skins, such as two of its terpenes, citronellol and nerol. On the other hand, increases in alcohol and ester values were registered with the application of ultrasound for 40 min. However, a significant decrease in these compounds was recorded when the ultrasound process was extended. In fact, when ultrasound was applied for 80 min, content values were even lower than those registered for the wine produced without the application of ultrasound. At the sensory level, the effect resulting from probe and bath ultrasound application for different times were compared, where most of the judges successfully discriminated the wines resulting from the application of ultrasound bath. According to data, the wines resulting from the application of ultrasound bath for 80 min presented the most significant differences, which affected the aromas of white fruit, tropical fruit, stone fruit, flowers and citrus.

A Study on Dynamic Simulation of Litchi Pitting Process Based on ANSYS / LS-DYNA

To study the dynamic mechanical changes in litchi pitting process and improve the accuracy of litchi pitting, this paper established a 3-D solid assembly model of litchi, fixture and tool and conducted the finite element discrete of the model by using ANSYS / LS-DYNA software. In addition, the deformations and stress states of litchi’s multi-layer structure under the effects of tool and fixture were simulated and calculated by the LS-DYNA971 solver. The results showed that the deformations and stresses of litchi’s multi-layer structure changed with the increase of cutting depth, and appeared the maximum amplitude out of sync. When the litchi was gonna cut through, the stress amplitude of fruit pulp was the maximum among litchi’s multi-layer structure and the stress amplitude of fruit pulp was the minimum. Pulp would reach its maximum stress when cutting through the litchi, and because of its low strength, the breakage was prone to occur. The stress of fruit stone was large in the initial stage, and big fruit stone was easily led to the breakage for its overlarge stress. In pitting process, the deformation and slippage of litchi would take place with fixture clamping and tool pitting, so this is a complex dynamic deformation process. This study is urgent to make more comprehensive and systematic researches.