Ultrazvukom potpomognuto prosijavanje prehrambenih praškastih materijala

undergraduate thesis

• Title (english): Ultrasonically assisted sieving of food powder materials
• Author: Lucija Vučko
• Mentor: Filip Dujmić (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Process Engineering); (Laboratory of Thermodynamics); Zagreb
• Defense date and country: 2018-07-09, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Klasičnim sijanjem praškastih materijala često dolazi do pojave aglomerata koji onemogućavaju ravnomjeran i potpun prolaz čestica kroz očice sita. U ovom završnom radu provedena je granulometrijska analiza uzoraka sa i bez primjene ultrazvuka visokog intenziteta i laserska analiza raspodjele veličine čestica pri čemu su korišteni uzorci smeđeg šećera i fruktoze, prethodno samljeveni na 6000 i 12000 o/min. Korištena su sita promjera očica: 355, 280, 180, 100, 56 i 20 μm. Uzorci su prosijani pri amplitudama trešnje od 1.0 i 2.0 mm u vremenskom intervalu od 3 sekunde, trajanju od 5 minuta sa i bez primjene ultrazvuka visokog intenziteta uz amplitudu od 80%. Rezultati granulometrijske analize prikazani su kao ovisnost relativne učestalosti o veličini otvora očica sita pri primijenjenoj amplitudi sijanja. Iz rezultata je vidljivo da primjena ultrazvuka poboljšala ujednačenost raspodjele veličine čestica. Najbolji rezultati postignuti su primjenom kombinacije ultrazvuka i amplitude trešnje od 2 mm.

Abstract (english)

Agglomeration phenomenon which prevents continuous passage of powder particles through sieve is the biggest problem of classical sieving. In this undergraduate thesis, granulometric analysis of samples with and without application of high intensity ultrasound and laser particle size distribution were conducted, using samples of brown sugar and fructose previously milled at 6000 and 12000 rpm. Sieve opening sizes were 355, 280, 180, 100, 56 and 20 μm. The samples were sieved at the amplitude of 1.0 and 2.0 mm in intervals of 3 seconds, during 5 minutes, with and without application of high intensity ultrasound (amplitude of 80%). Results of sieving analysis are presented as a step-like frequency distribution curve at a determined amplitude of ultrasound. It is shown that the high intensity ultrasound enhances the effect of sieving. The best results were achieved with a combination of ultrasound and 2.0 mm amplitude.

• Keywords: ultrazvuk; raspodjela veličine čestica; laserska difrakcija
• Keywords (english): ultrasound; particle size distribution; laser diffraction
• Language: croatian
• URN:NBN: urn:nbn:hr:159:641658
• Study programme: Title: Biotechnology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2018-07-18 09:30:24