RELATIONSHIP BETWEEN THE THICKNESS OF THE FOOD PRODUCT GETTING CUT BY A DISC KNIFE AND FRICTION FORCE Текст научной статьи по специальности «Электротехника, электронная техника, информационные технологии»

REFERENCES

1. Deliiska B., Todorov B., Danchev A. 2004. Educational aspects of geoinformatics implementation (case study of Bulgaria), Proceedings of "3-rd GIS Days in Turkey/October 6-9, 2004", 163-169.

2. Kerski, J. 2003. The Implementation and Effectiveness of Geographic Information Systems Technology in Secondary Education. Journal of Geography, 102(3): 128-137.

3. Laituri, Melinda, and Sophia Linn. 2001. Graduate students plus Grade School (K-12) plus Geography Standards plus GIS = Great Success! Proceedings of the 1999 ESRI User Conference.

RELATIONSHIP BETWEEN THE THICKNESS OF THE FOOD PRODUCT GETTING CUT BY A DISC KNIFE AND FRICTION FORCE

PhD Professor Eng. Vasilev S.

Ilieva I.

Bulgaria, Plovdiv, University of Food Technologies

Abstract. Subject of the present theoretical study is the cutting process, which is one of the most common processes in the different sectors of the food industry. Cutting devices using disc knives

are discussed. A study is proposed on the influence of the geometrical parameter B , representing the thickness of the product getting cut, on the resultant friction force.

Keywords: resultant friction force, disc knife, food, relative deviation, linearity

Introduction. A number of food products are effectively cut with disc knives with smooth cutting edge. Due to the elasticity of the food products, the deformation that arises during their dissection causes friction forces between the side walls of the knife and the product. Given these frictional forces formula is derived for the resultant frictional force [1]:

T = f V2 J - (r - A - B)2 J5 + B(2r - 2A- B)tg№]

l , (1)

where

f - coefficient of friction between the product getting cut and the knife;

E - modulus of elasticity of the product getting cut, Pa ;

a - half of the disc knife's width, m ;

l - width of the product getting cut from one side of the knife, m ;

r - radius of the disc knife, m ;

B - thickness of the product getting cut, m ;

A - height of the disc blade's part, which is incised in the board, m ;

Parameters J4 and J5 are called first and second resistance characteristics and are given by the following elliptic integrals

№ 2cos№-1 , r № 2cos№-1 1

J4 = 1 1 , =d(P J 5 =J —;—I , =d(P

icpi V1 + 2 - 22 cos № . №l cos2 № 1 + 22 - 22cos^ .

; ; (2)

v

Here A = — is a velocity coefficient, which is the ratio between the cutting speed v p and

feed rate Vn . The effect of velocity coefficient on the cutting forces of food was researched by a lot of scientists [2,3,4].

The limits of the integrals J4 and J 5 are determined by

r-A r-A-B pl = arccos- pu = arccos-

r ; r (3)

Parameters J , E , a and l depend on the nature of the product getting cut and are derived

experimentally. The values of r , B , A and X are still subject to both theoretical and experimental studies.

This work offers a study on the influence of the geometrical parameter B on the resultant friction force.

Output data. Object of the current research is a double beveled disc knife with smooth edge. Numerical analysis for a raw material meat has done with the following parameters:

j = 0.05; E = 12.103 Pa ■ a = 0.15.10-3 m ;

l = 0.45.10-3 m ; r = 0.105 m ■ X = 10.

Numerical analysis. Base on the practical investigation the following relations are obtained

B < 2 r

- 3 ; A< 0.1 B (4)

According to the upper formulas are taken the next values of the thickness of the product getting cut and the height of the disc blade's part, which is incised in the board respectively

B = 0.01,0.02,0.03,0.05,0.07

m

A = 0.001,0.002,0.003,0.005,0.007

' ' ' ' , m (5)

Due to the given values of the considered parameters the resistance characteristics and the resultant friction force are solved and shown in a table 1 and figures 1, 2 and 3.

Table 1. Values of the resultant resistances when the thickness of the product getting cut is on the interval B e [0.01,0.07]

B, m 0.01 0.02 0.03 0.05 0.07

J4 0.3044 0.4085 0.4731 0.5391 0.5498

J 5 0.3366 0.5032 0.6549 0.9741 1.376

Tx, * 0.1314 0.3547 0.6193 1.182 1.675

At first sight graphs of the relationships shown in fig. 2 and fig. 3 are close to linear. This is the reason why further investigations are done.

Let us assume the later quantitative assessment of relative deviation of linearity S :

• when S < 5% we accept that the function is linear;

• when S > 5% we do not accept that the function is linear.

First step is to draw a straight line L through the endpoints of the graph of the function T = T (B) on the interval B e [0.01,0.07] (fig. 4).

Fig. 1. Relationship between the first Fig. 2. Relationship between the second

resistance characteristic and parameter B resistance characteristic and parameter B

Fig. 3. Relationship between the resultant Fig. 4. Deviation of linearity of the resultant friction force and parameter B friction force Tx as a function of the

parameter B

The given interval is divided into 11 subintervals. The biggest distance between the corresponding coordinates of the two graphs is d^ = 0.0348401 and is reached where the

coordinates of the point of the Tx are (0.022,0.405271). We denote with max T = 0.405271 the

value of the resultant friction force, where is the biggest distance dmax and with Stx the relevant deviation of linearity. Thus

S % = -^100 = 0 0348401100 - 8.59% . Tx max T 0.405271

Using the same pattern the relevant deviation of linearity of the characteristic J5 is obtained

S % = —dmax—100 = 0 0548158100 - 5.40%. J5 max J 1.00935

By the fact that the relevant deviation of linearity of the graph of Tx and J 5 is bigger than

5% follows that both relationships can not be accepted to be linear.

Conclusion. When parameter B , representing the thickness of the product getting cut, increases, the resultant friction force during disc knife cutting of food products caused by the friction between the material and the knife side walls, increases as well.

The relationship between the resultant friction force and parameter B is not a linear. The obtained results are related with characteristics of the process of cutting with disc knife and can be used for design of different cutting tools.

REFERENCES

1. Vasilev S., Modelirane i dinamichen analiz na mehanichni protsesi i sistemi v hranitelno vkusovata promishlenost, Habilitatsionen trud, Plovdiv, 2010.

2. Даурский А. Н., Ю. А. Мачихин, Резание пищевых материалов, Москва, Пищевая промышленность, 1980.

3. Ilieva I. (2016). Relationship between the velocity coefficient and moment of force to cutting with disc knife. International scientific and practical conference "World science (The goals of the WorldScience 2016 (January 27 - 28, 2016, Dubai, UAE)"), 2(6), Vol. 1, 19 - 21.

4. Boteva M., I. Mihaylov, I. Shopov (2016). Research of the effect of the velocity coefficient on the cutting force of vegetables. International scientific and practical conference "World science (The goals of the WorldScience 2016 (January 27 - 28, 2016, Dubai, UAE)"), 2(6), Vol. 1, 19 - 21.

ЗАХИСТ КАНАЛУ ЗВ'ЯЗКУ WI-FI М1Ж ПУЛЬТОМ КЕРУВАННЯ ТА БЕЗП1ЛОТНИМ АПАРАТОМ В1Д НЕСАНКЦ1ОНОВАНОГО ДОСТУПУ

проф. Власюк Г. Г., доц. Ствак В. М., проф. Розоринов Г. М.

Укрална, Нацюнальний техшчний утверситет Укрални "Кшвський полтехшчний

шститут "

Abstract. A question of communication channel safety between a unmanned unmanned vehicle and control stand is considered, the necessity of channel defence from an unauthorized access is grounded, the classification of threat types for informative safety is formed.

Keyword: Informative safety, unmanned vehicle, communication channel, Wi-Fi, encryption, cryptography, access point.

Останшм часом безпшотш апарати з каналом бездротового зв'язку Wi-Fi (Wireless Fidelity) отримали величезне розповсюдження. Сьогодш вони можуть бути використаш як у кшошдустри , у розважальних цшях, як вид спортивно! дисциплши, як мобшьш камери вщео-нагляду так i у наукових цшях, з метою дослщження важко доступних мюць (жерло вулкана, гори i т. д). 1хне використання може бути зумовлене одним iз наступних чинниюв: необхщшсть забезпечення мобшьносп, неможливють використання дротово! мереж^ вщсутшсть шших бездротових технологш у робочш зош.

Також безпшотш апарати з каналом зв'язку Wi-Fi о^м передавання вiзуальноl шформацп, використовуються як кур'ерсью дрони. Тому дослщження способiв та засобiв захисту вщ несанкщонованого доступу каналу зв'язку, а саме, систем безпеки мiж безпшотним апаратом та пультом керування е актуальним.

Формулювання проблеми захисту каналу зв'язку

Щд системою шформацшно! безпеки, функщональна схема котро! наведена на рис.1, будемо розумгги оргашзовану сукупнють спещальних оргашв, служб, засобiв, методiв i заходiв, що забезпечують захист каналу зв'язку [1].

Розумiючи iнформацiйну безпеку як «стан захищеностi шформацшного середовища, що забезпечуе li формування, використання i розвиток в штересах громадян, оргашзацш», правомiрно визначити загрози безпеки шформацп, джерела цих загроз, способи 1х реалiзацil та мети, а також iншi умови i ди, що порушують безпеку. При цьому, природно, слщ розглядати i заходи захисту шформацп вiд неправомiрних дiй, що призводять до нанесення збитку [3].