Solving the Problem of Friction and Wear in Auxiliary Devices of Internal Combustion Engines on the Example of Reciprocating Air Compressor for Vehicles

Using vehicles and other mobile systems to transport passengers and goods, approximately 25% of Europe\u27s greenhouse gases are generated. At the same time, many research papers, published by researchers and students, promote the use of electric vehicles as zero-emission vehicles. Given that, more broadly, the emission of electric vehicles is higher, especially in countries where electricity is obtained by burning coal, the use of internal-combustion engines is still dominant. There are other reasons for using an internal-combustion engine, such as already developed pumping station infrastructure, which is not the case when recharging electric vehicles. Improvements in engine design contribute to meet the regulations relating to the fuel consumption and toxic gas emissions. This refers to the use of alternative fuels, improving the combustion process, and increasing efficiency (efficiency coefficient) by reducing losses. The research is focused on the problem of friction and wear in internal combustion engines and reciprocating air compressors, as auxiliary devices on engines. For that purpose, construction of the reciprocating air compressor in motor vehicles was redesigned. The paper presents the characteristic test results of material used to strengthen liner of the aluminum cylinder. Specifically, a method for testing the performance characteristics of a single-cylinder reciprocating compressor inside of an experimental installation for compressed air supply has also been proposed

Ranking of Logistics System Scenarios for Central Business District

This paper presents the procedure for logistics system scenario selection for the central business district (CBD) of the city in the phase of significant urban changes. Scenarios are defined in accordance with the overall logistics concept of the city. Conflicting goals of stakeholders (residents, shippers and receivers, logistics providers and city government) generate a vast number of criteria that need to be included when selecting the scenario for the city area logistics system. Due to limited resources and linguistic assessment of criteria, fuzzy extensions of conventional multi-criteria decision-making (MCDM) methods were used. Fuzzy "analytical hierarchy process" (FAHP) is applied to determine the relative weights of evaluation criteria, and fuzzy "technique for order preference by similarity to ideal solution" (FTOPSIS) is applied to rank the logistics systems scenarios. This paper contributes to the literature in the field of city logistics (CL), as it applies the integrated FAHP-FTOPSIS method for the evaluation of scenarios, which are also integrated combinations of different CL initiatives. The integrated combined approach proved to be accurate, effective and a systematic tool for the decision support in the process of selecting CBD logistics scenarios

New insights into sesquiterpene lactones composition of Western Balkan’s genus Amphoricarpos revealed by rapid resolution liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

This study revealed results from reinvestigation of sesquiterpene lactones composition in the crude and leaf surface extracts of Amphoricarpos plants by rapid resolution liquid chromatography (RRLC) coupled with quadrupole time-of-flight mass spectrometry (QToF MS) and the tentative identification of undescribed sesquiterpene lactones is presented.11th Conference on Medicinal and Aromatic Plants of Southeast European Countries, (11th CMAPSEEC), Ohrid, North Macedonia, 6–10 October 202

Correlation between Emission and Combustion Characteristics with the Compression Ratio and Fuel Injection Timing in Tribologically Optimized Diesel Engine

Diesel engines are economical thanks to their combustion process characteristics, which is why they have a high noise emission level as well as exhaust emissions of nitrogen oxide and particulate matters. By continuously changing the value of compression ratio, it is possible to control the power and emissions. Implementation of variable compression ratio has many benefits, such as being able to work with different types of fuel. In this way, it is possible to optimize the combustion process for operation with minimum fuel consumption and emission generation, so that diesel engines can be applied to the framework of future hybrid vehicle concepts, and so forth. As far as the crucial objective of the manuscript is concerned, experimental diesel engine investigation was performed on a roller test-bench by using zero-dimensional computer model (specifically AVL IndiCom Indicate Software). Engine indication was executed with the factory compression ratio value and with three lower values. During our examination, the change in the compression ratio value was achieved by changing the volume of a combustion chamber at a piston-bowl. The results of laboratory research on the experimental engine are presented in the paper when discussing a series of specific parameters (characteristics), such as compression ratio, fuel injection timing, engine speed, as well as load influence on combustion process and exhaust emissions

Tuta absoluta (Meyrick, 1917) (Lepidoptera, Gelechiidae) - nova štetočina paradajza u Srbiji

Tomato leaf miner Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), a devastating pest of tomato originating from South America has been recorded in Serbia on three localities: in tomato main greenhouse and open field production area located in the vicinity of town Leskovac (South Serbia), in surroundings of the village Donji Vrtogoš (near town Vranje, South Serbia) and in a greenhouses complex in Kraljevci (60 km west of Belgrade). The presence of T. absoluta was confirmed by morphological and molecular study of the collected specimens.Prisustvo lisnog minera paradajza Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), opasne štetočine poreklom iz Južne Amerike, utvrđeno je na tri lokaliteta u Srbiji: u plastenicima i poljima u okolini Leskovca (južna Srbija), u okolini sela Donji Vrtogoš (u blizini Vranja) i u kompleksu plastenika u selu Kraljevci (60 km zapadno od Beograda). Identifikacija T. absoluta je izvršena morfološkim i molekularnim analizama sakupljenih uzoraka

Anti-melanoma effects of ingenanes isolated from Euphorbia species

In this research, from two species, E. palustris and E. lucida, four ingenane derivatives were isolated. Their anticancer effects were evaluated in the human melanoma – 518A2 cell line and compared with the effects of ingenolmebutate. Selectivity towards human melanoma cells was determined using normal human keratinocytes – HaCaT.11th Conference on Medicinal and Aromatic Plants of Southeast European Countries, (11th CMAPSEEC), Ohrid, North Macedonia, 6–10 October 202

Socijalna validnost treninga socijalnih veština – perspektiva roditelja/staratelja

Socijalna validnost predstavlja multidimenzionalni konstrukt koji upućuje na stepen u kojem korisnici nekog tretmana, poput učenika, i oni koji su direktno ili indirektno uključeni u realizaciju tretmana, poput nastavnika i roditelja, opažaju dati tretman kao prihvatljiv način kojim se mogu ostvariti socijalno značajni ciljevi i socijalno važni ishodi. Socijalna validnost tretmana i ciljeva koji se njime ostvaruju ima prediktivnu vrednost u pogledu integriteta sprovođenja tretmana i dugoročnog održavanja njegovih efekata. Cilj istraživanja bio je da se utvrdi socijalna validnost treninga socijalnih veština za učenike sa intelektualnom ometenošću i/ili autizmom, iz perspektive njihovih roditelja/staratelja. U istraživanju su učestvovali roditelji/staratelji (N = 30) čija su deca uključena u trening socijalnih veština koji se sprovodi u Osnovnoj školi za učenike sa smetnjama u razvoju i invaliditetom ,,Miloje Pavlović” iz Beograda. Za procenu socijalne validnosti korišćena je modifikovana verzija skraćene forme Inventara za evaluaciju tretmana (Treatment evaluation inventory short form, TEI-SF). Od ispitanika se tražilo da na šestostepnoj skali označe svoj stepen slaganja sa datim tvrdnjama (minimalna ocena 1, maksimalna ocena 6). Viši skorovi upućuju na pozitivnije stavove prema tretmanu. U našem istraživanju skala je imala zadovoljavajuću internu konzistentnost (α = 0,88). Rezultati ukazuju na visok nivo socijalne validnosti kada se posmatra skala u celini (AS = 5,13, SD = 0,74), pri čemu su prosečni skorovi na pojedinačnim stavkama bili u ospegu od 3,60 do 5,54. Generalno, roditeljima/starteljima se dopadaju procedure koje se koriste u okviru treninga (AS =5,54 , SD = 1,04), smatraju trening prihvatljivim (AS = 5,45 , SD = 0,99) i efikasnim načinom za rešavanje socijalnih poteškoća deteta (AS = 5,41 , SD = 0,98), kojim se mogu ostvariti trajna poboljšanja (AS =5,13 , SD = 0,78). Međutim, oni iskazuju donekle umerene stavove u pogledu osećanja lagodnosti deteta tokom treninga (AS = 3,60, SD = 1,83). Dobijeni pozitivni stavovi roditelja/staratelja prema primeni treninga socijalnih veština su ohrabrujući s obzirom na to da povećavaju verovatnoću da će trening biti primenjen na način na koji je planiran, a koji podrazumeva i kreiranje brojnih prilika za vežbanje i generalizaciju socijalnih veština u vanškolskom okruženju

Socijalna validnost treninga socijalnih veština – perspektiva roditelja/staratelja

Socijalna validnost predstavlja multidimenzionalni konstrukt koji upućuje na stepen u kojem korisnici nekog tretmana, poput učenika, i oni koji su direktno ili indirektno uključeni u realizaciju tretmana, poput nastavnika i roditelja, opažaju dati tretman kao prihvatljiv način kojim se mogu ostvariti socijalno značajni ciljevi i socijalno važni ishodi. Socijalna validnost tretmana i ciljeva koji se njime ostvaruju ima prediktivnu vrednost u pogledu integriteta sprovođenja tretmana i dugoročnog održavanja njegovih efekata. Cilj istraživanja bio je da se utvrdi socijalna validnost treninga socijalnih veština za učenike sa intelektualnom ometenošću i/ili autizmom, iz perspektive njihovih roditelja/staratelja. U istraživanju su učestvovali roditelji/staratelji (N = 30) čija su deca uključena u trening socijalnih veština koji se sprovodi u Osnovnoj školi za učenike sa smetnjama u razvoju i invaliditetom ,,Miloje Pavlović” iz Beograda. Za procenu socijalne validnosti korišćena je modifikovana verzija skraćene forme Inventara za evaluaciju tretmana (Treatment evaluation inventory short form, TEI-SF). Od ispitanika se tražilo da na šestostepnoj skali označe svoj stepen slaganja sa datim tvrdnjama (minimalna ocena 1, maksimalna ocena 6). Viši skorovi upućuju na pozitivnije stavove prema tretmanu. U našem istraživanju skala je imala zadovoljavajuću internu konzistentnost (α = 0,88). Rezultati ukazuju na visok nivo socijalne validnosti kada se posmatra skala u celini (AS = 5,13, SD = 0,74), pri čemu su prosečni skorovi na pojedinačnim stavkama bili u ospegu od 3,60 do 5,54. Generalno, roditeljima/starteljima se dopadaju procedure koje se koriste u okviru treninga (AS =5,54 , SD = 1,04), smatraju trening prihvatljivim (AS = 5,45 , SD = 0,99) i efikasnim načinom za rešavanje socijalnih poteškoća deteta (AS = 5,41 , SD = 0,98), kojim se mogu ostvariti trajna poboljšanja (AS =5,13 , SD = 0,78). Međutim, oni iskazuju donekle umerene stavove u pogledu osećanja lagodnosti deteta tokom treninga (AS = 3,60, SD = 1,83). Dobijeni pozitivni stavovi roditelja/staratelja prema primeni treninga socijalnih veština su ohrabrujući s obzirom na to da povećavaju verovatnoću da će trening biti primenjen na način na koji je planiran, a koji podrazumeva i kreiranje brojnih prilika za vežbanje i generalizaciju socijalnih veština u vanškolskom okruženju

Combined GSTM1 and GSTT1 null genotypes are strong risk factors for atherogenesis in a Serbian population

Oxidative stress (OS) plays an important role in atherogenesis and since glutathione S-transferases (GSTs) provide protection against OS, we have tested the hypothesis that deletion polymorphisms in two GSTs (GSTM1 and GSTT1) may affect the risk of developing atherosclerosis. A total of 382 individuals (200 patients with atherosclerosis and 182 healthy controls) were included in this association study. Genomic DNA was isolated from peripheral blood cells or from buccal epithelial cells and genotyping was performed using multiplex-PCR or real-time PCR methods. GSTM1 null genotype was significantly more frequent in atherosclerotic patients than in controls (52.0% vs 34.1%) and individuals with the GSTM1 null genotype had an approximately 2-fold increase in atherosclerosis risk (OR: 2.1, 95%CI=1.39-3.17, P=0.0004). GSTT1 null genotype alone did not show a statistically significant effect on atherosclerosis risk modulation, but the association approached significance (OR: 1.57, 95%CI=0.94-2.64, P=0.08). The combined analysis showed that the presence of both genes had a protective effect against atherosclerosis (OR=0.55, 95%CI=0.37-0.83, P=0.005) while double null genotypes led to a robust atherosclerosis risk increase (OR: 8.14, 95%CI=2.41-27.51, P lt 0.0001). This study demonstrated that the GSTM1 null and combined GSTM1/GSTT1 null genotypes are susceptibility factors for development of atherosclerosis in a Serbian population

Senzorna dijeta kod dece s poremećajem iz spektra autizma – zablude ili dokazi?

Implementacija senzorne dijete podrazumeva senzornu strategiju koja se često koristi kod dece s poremećajem iz spektra autizma (PSA) u cilju omogućavanja podizanja kvaliteta senzorne obrade i interakcije tokom izvršavanja svakodnevnih zadataka. To se postiže kontrolisanim unosom senzornih nadražaja kako bi se smanjila senzorna defanzivnost. Moglo bi se reći da je to individualizovani plan potpuno prilagođen karakteristikama senzorne obrade u svrhu omogućavanja optimalnog funkcionisanja. Čini je dnevna ili nedeljna lista aktivnosti kojima dete s PSA može da bude angažovano tokom redovnih rutina radi održavanja optimalnog stanja senzornog sistema. Pre izrade individualizovanog plana neophodno je napraviti procenu sposobnosti koje su relevantne za izradu senzornog profila deteta s PSA. Skrining teškoća senzorne obrade moguće je izvršiti koristeći Dečiji senzorni profil 2 (The Child Sensory Profile 2, Dunn, 2014). Ovim instrumentom vrši se merenje specifikacija senzornih odgovora ispitanika uzrasta od 4 do 14 godina i 11 meseci. Primena senzorne dijete zahteva planiranje aktivnosti i dosledan monitoring kako bi se, kao krajnji cilj, ostvarila adaptibilna responzivnost. Nesporno je postojanje pojedinačnih istraživačkih studija koje su istakle pozitivne promene u domenu nekoliko razvojnih oblasti (socijalne veštine, ponašanje u vrtiću, senzorna obrada) primenom senzorne dijete. Neka od istraživanja definišu senzornu dijetu kao intervenciju zasnovanu na praksi, kao što je vežbanje ili potkrepljenje. Ipak, važno je istaći da ova strategija nije navedena u skupini intervencija zasnovanih na dokazima koje podržava Nacionalni razvojni centar za poremećaje iz spektra autizma (National Professional Development Center on Autism Spectrum Disorders, US Department of Education). Zato se u brojnim radovima preporučuje dalje kontinuirano proučavanje primene senzorne dijete, senzornih strategija i funkcionalnih ishoda kvalitetnije senzorne obrade.Dani defektologa Srbij