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This study aimed to determine the effects of continued use of petroleum diesel and biodiesel fuel blend on the changes in engine performances and exhaust gas emissions of the IC engine. The experiments were conducted on a tractor engine using a blend of biodiesel and petroleum diesel in the ratio of 40:60% (v.v−1) (BD40). The tractor performed standard farming operations using BD40 fuel for 1000 h. The engine performances and exhaust gas emissions were evaluated at the beginning of the experiment and after 100, 250, 500, and 1000 h. Maximum engine power dropped by 6.16% after 1000 h with BD40 fuel, and specific fuel consumption and CO emission increased by 7.35 and 12.5% respectively. The CO2 emission was reduced by 6.26%. Worsened engine performance was probably a consequence of the deposit on the tip of injectors which was formed due to thermal oxidation of unsaturated fatty acids that amounted to over 90% in the used raw material for biodiesel production. Statistical analysis of the obtained data indicated statistically significant changes.
M. Tomić; L. Savin; M. Simikić; F. Kiss; K. Kešelj; M. Ivanišević; O. Ponjičan; M. Zoranović; A. Sedlar. Effects of biodiesel on changes in IC engine performances: A long-term experiment with farm tractors. Fuel 2021, 292, 120300 .
AMA StyleM. Tomić, L. Savin, M. Simikić, F. Kiss, K. Kešelj, M. Ivanišević, O. Ponjičan, M. Zoranović, A. Sedlar. Effects of biodiesel on changes in IC engine performances: A long-term experiment with farm tractors. Fuel. 2021; 292 ():120300.
Chicago/Turabian StyleM. Tomić; L. Savin; M. Simikić; F. Kiss; K. Kešelj; M. Ivanišević; O. Ponjičan; M. Zoranović; A. Sedlar. 2021. "Effects of biodiesel on changes in IC engine performances: A long-term experiment with farm tractors." Fuel 292, no. : 120300.
This study aimed to determine the effects of osmotic dehydration on the kinetics of hot air drying of apricot halves under conditions that were similar to the industrial ones. The osmotic process was performed in a sucrose solution at 40 and 60 °C and concentrations of 50% and 65%. As expected increased temperatures and concentrations of the solution resulted in increased water loss, solid gain and shrinkage. The kinetics of osmotic dehydration were well described by the Peleg model. The effective diffusivity of water 5.50–7.387 × 10−9 m2/s and solute 8.315 × 10−10–1.113 × 10−9 m2/s was calculated for osmotic dehydration. Hot air drying was carried out at 40, 50, and 60 °C with air flow velocities of 1.0 m/s and 1.5 m/s. The drying time shortened with higher temperature and air velocity. The calculated effective diffusion of water was from 3.002 × 10−10 m2/s to 1.970 × 10−9 m2/s. The activation energy was sensitive to selected air temperatures, so greater air velocity resulted in greater activation energy: 46.379–51.514 kJ/mol, and with the osmotic pretreatment, it decreased to 35.216–46.469 kJ/mol. Osmotic dehydration reduced the effective diffusivity of water during the hot air drying process. It also resulted in smaller shrinkage of apricot halves in the hot air drying process.
Ivan Pavkov; Milivoj Radojčin; Zoran Stamenković; Krstan Kešelj; Urszula Tylewicz; Péter Sipos; Ondrej Ponjičan; Aleksandar Sedlar. Effects of Osmotic Dehydration on the Hot Air Drying of Apricot Halves: Drying Kinetics, Mass Transfer, and Shrinkage. Processes 2021, 9, 202 .
AMA StyleIvan Pavkov, Milivoj Radojčin, Zoran Stamenković, Krstan Kešelj, Urszula Tylewicz, Péter Sipos, Ondrej Ponjičan, Aleksandar Sedlar. Effects of Osmotic Dehydration on the Hot Air Drying of Apricot Halves: Drying Kinetics, Mass Transfer, and Shrinkage. Processes. 2021; 9 (2):202.
Chicago/Turabian StyleIvan Pavkov; Milivoj Radojčin; Zoran Stamenković; Krstan Kešelj; Urszula Tylewicz; Péter Sipos; Ondrej Ponjičan; Aleksandar Sedlar. 2021. "Effects of Osmotic Dehydration on the Hot Air Drying of Apricot Halves: Drying Kinetics, Mass Transfer, and Shrinkage." Processes 9, no. 2: 202.
Drying is one of the oldest methods for food preservation that removes the water from fruit and makes it available for consumption throughout the year. Dried fruits can be produced by small- and large-scale processors, which makes them a very popular food among consumers and food manufacturers. The most frequent uses of drying technology include osmotic dehydration, vacuum drying, freeze-drying and different combinations of other drying technologies. However, drying may provoke undesirable changes with respect to physiochemical, sensory, nutritional and microbiological quality. Drying process energy efficiency and the quality of dried fruits are crucial factors in fruit drying. Recently, innovative technologies such as ultrasound, pulsed electric field and high pressure may be used as a pretreatment or in combination with traditional drying technologies for process intensification. This could result in quality improvements of dried fruits and enhanced efficiency and capacity of the production process, with a positive impact on environmental and economic benefits.
Milivoj Radojčin; Ivan Pavkov; Danijela Bursać Kovačević; Predrag Putnik; Artur Wiktor; Zoran Stamenković; Krstan Kešelj; Attila Gere. Effect of Selected Drying Methods and Emerging Drying Intensification Technologies on the Quality of Dried Fruit: A Review. Processes 2021, 9, 132 .
AMA StyleMilivoj Radojčin, Ivan Pavkov, Danijela Bursać Kovačević, Predrag Putnik, Artur Wiktor, Zoran Stamenković, Krstan Kešelj, Attila Gere. Effect of Selected Drying Methods and Emerging Drying Intensification Technologies on the Quality of Dried Fruit: A Review. Processes. 2021; 9 (1):132.
Chicago/Turabian StyleMilivoj Radojčin; Ivan Pavkov; Danijela Bursać Kovačević; Predrag Putnik; Artur Wiktor; Zoran Stamenković; Krstan Kešelj; Attila Gere. 2021. "Effect of Selected Drying Methods and Emerging Drying Intensification Technologies on the Quality of Dried Fruit: A Review." Processes 9, no. 1: 132.
Raspberries are one of Serbia’s best-known and most widely exported fruits. Due to market fluctuation, producers are looking for ways to preserve this fresh product. Drying is a widely accepted method for preserving berries, as is the case with freeze-drying. Hence, the aim was to evaluate convective drying as an alternative to freeze-drying due to better accessibility, simplicity, and cost-effectiveness of Polana raspberries and compare it to a freeze-drying. Three factors were in experimental design: air temperature (60, 70, and 80 °C), air velocity (0,5 and 1,5 m · s−1), and state of a product (fresh and frozen). Success of drying was evaluated with several quality criteria: shrinkage (change of volume), color change, shape, content of L-ascorbic acid, total phenolic content, flavonoid content, anthocyanin content, and antioxidant activity. A considerable influence of convective drying on color changes was not observed, as ΔE was low for all samples. It was obvious that fresh raspberries had less physical changes than frozen ones. On average, convective drying reduced L–ascorbic acid content by 80.00–99.99%, but less than 60% for other biologically active compounds as compared to fresh raspberries. Convective dried Polana raspberry may be considered as a viable replacement for freeze-dried raspberries.
Zoran Stamenković; Ivan Pavkov; Milivoj Radojčin; Aleksandra Tepić Horecki; Krstan Kešelj; Danijela Bursać Kovačević; Predrag Putnik. Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties. Foods 2019, 8, 251 .
AMA StyleZoran Stamenković, Ivan Pavkov, Milivoj Radojčin, Aleksandra Tepić Horecki, Krstan Kešelj, Danijela Bursać Kovačević, Predrag Putnik. Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties. Foods. 2019; 8 (7):251.
Chicago/Turabian StyleZoran Stamenković; Ivan Pavkov; Milivoj Radojčin; Aleksandra Tepić Horecki; Krstan Kešelj; Danijela Bursać Kovačević; Predrag Putnik. 2019. "Convective Drying of Fresh and Frozen Raspberries and Change of Their Physical and Nutritive Properties." Foods 8, no. 7: 251.
The purpose of this paper is to examine the effects of storage and treatment with sulfur dioxide of different concentration on the overall change in the color of dried apricots. Upon sulfurization of the prepared apricot samples, they were dried using the combined osmotic-convective drying technology, and subsequently kept either in a storage unit at t ≈ 25 o C or in a cooled environment at t ≈ 3 o C over a period of six months. The sample color was measured on the inside and the outside of the dried apricot fruits. Statistical analysis was performed using the Dependent Samples T-test so as to determine changes in the color of dried apricots after 3 and 6 months of storage. After six months of storage, the smallest color change of ∆E = 6.56 was measured in the apricot samples stored in a cooled environment. After six months, the greatest color change of ∆E = 49.38 was measured in the apricot samples stored at an air temperature of 25 o C.
Krstan Kešelj; Mirko Babić; Ivan Pavkov; Milivoj Radojčin; Zoran Stamenković; Dragana Tekić; Mladen Ivanišević. Effects of storage and sulfurization with sulfur dioxide of different concentration on changes in the color of dried apricots. Journal on Processing and Energy in Agriculture 2019, 23, 190 -194.
AMA StyleKrstan Kešelj, Mirko Babić, Ivan Pavkov, Milivoj Radojčin, Zoran Stamenković, Dragana Tekić, Mladen Ivanišević. Effects of storage and sulfurization with sulfur dioxide of different concentration on changes in the color of dried apricots. Journal on Processing and Energy in Agriculture. 2019; 23 (4):190-194.
Chicago/Turabian StyleKrstan Kešelj; Mirko Babić; Ivan Pavkov; Milivoj Radojčin; Zoran Stamenković; Dragana Tekić; Mladen Ivanišević. 2019. "Effects of storage and sulfurization with sulfur dioxide of different concentration on changes in the color of dried apricots." Journal on Processing and Energy in Agriculture 23, no. 4: 190-194.
Sušenje maline obavlja se sušenjem zamrzavanjem (liofilizacija). Dobijeni proizvod je kvalitetan. Liofilizacija je skup process. U radu upoređena je potrošnja energije i dužina trajanja procesa pri sušenju 100 kg maline postupkom sublimacionog sušenja i konvektivnog sušenja. Konvektivno sušenje obavljeno je u labaratorijskoj sušari 'IVA-2' na Poljoprivrednom fakultetu u Novom Sadu. Za sušenje zamrzavanjem korišćen je labaratojiski liofilizator 2-4 LD plus, švajcarskog proizvođača Marthin Christ. Obavio se proračun potrošnje energije za oba oblika sušenja kao i njihovo poređenje. Prilikom proračuna potrošnje energije obratila se pažnja na sve potrošače uključene u process sušenja (direktno i indirektno). Obavio se proračun potrošnje energije za svaki postupak sušenja pojedinačno. Kod svakog procesa izdvojili su se glavni potrošači i izračunata je njihova potrošnja. Kod sublimacionog sušenja glavni potrošačai su bili su: komora za zamrzavanje, liofilizator i vakum pumpa. Kod postupka konvektivnog sušenja ti potrošači bili su aksijalni ventilator i grejna tela tj. toplotna energija potrebna za isparavnje vlage iz maline. Takođe je utvrđena i dužina trajanja procesa sušenja. Dobijeni rezultati sušenja oba slučaja upoređeni su jedni sa drugima. Rezultati su pokazali da je potrošnja energije za process sušenja zamrzavanjem veća od procesa sušenja konvektivnom metodom. Dužina sušenja zamrzavanjem duže traje od sušenja konvektivnim postupkom. potrošnja energije; sušenje zamrzavanjem; liofilizacija; konvektivno sušenje; malina
Krstan Keselj; Ivan Pavkov; Milivoj Radojcin; Zoran Stamenkovic. Comparison of energy consumption in the convective and freeze drying of raspberries. Journal on Processing and Energy in Agriculture 2017, 21, 192 -196.
AMA StyleKrstan Keselj, Ivan Pavkov, Milivoj Radojcin, Zoran Stamenkovic. Comparison of energy consumption in the convective and freeze drying of raspberries. Journal on Processing and Energy in Agriculture. 2017; 21 (4):192-196.
Chicago/Turabian StyleKrstan Keselj; Ivan Pavkov; Milivoj Radojcin; Zoran Stamenkovic. 2017. "Comparison of energy consumption in the convective and freeze drying of raspberries." Journal on Processing and Energy in Agriculture 21, no. 4: 192-196.