Reasoning with linguistic preferences using NPN logic

Negative-positive-neutral logic provides an alternative framework for fuzzy cognitive maps development and decision analysis. This paper reviews basic notion of NPN logic and NPN relations and proposes adaptive approach to causality weights assessment. It employs linguistic models of causality weights activated by measurement-based fuzzy cognitive maps' concepts values. These models allow for quasi-dynamical adaptation to the change of concepts values, providing deeper understanding of possible side effects. Since in the real-world environments almost every decision has its consequences, presenting very valuable portion of information upon which we also make our decisions, the knowledge about the side effects enables more reliable decision analysis and directs actions of decision maker

Formaldehyde in screen printing indoor

The presence of formaldehyde in air samples has been detected in five screen printing facilities in Novi Sad, Serbia. Air samples were sampled continuously during 4 hours, and concentration levels of formaldehyde was determined by UV-VIS spectrometry at 580 nm. The range of formaldehyde concentrations was from 0.413 to 0.836 ppm. Comparison of the detected concentration levels with the permissible exposure limit of 0.75 ppm (the OSHA standard) indicated that the formaldehyde concentration in facility 5 was 1.11 times higher than prescribed value

MICROSTRUCTURE INFLUENCE ON FRICTION BEHAVIOR OF THE TI6AL4V BIOMEDICAL ALLOY AT LOW LOADS

Dynamic friction coefficient (COF) between Ti6Al4V and Al2O3 was analyzed under low loads (100 mN, 250 mN, 500 mN, 750 mN, 1000 mN), sliding speed (4 mm/s, 8 mm/s, 12 mm/s) at dry contact and in the Ringer's solution. Different Ti6Al4V microstructures were studied: Sample 1 - fully lamellar; Sample 2 - martensitic; sample 3 - equiaxed; and sample 4 - globular microstructure. The maximum COF values varied as: 0.4 - 1.23 (Sample 1), 0.5 – 2.8 (Sample 2), 0.4 – 1.1 (Sample 3), and 0.4 – 2.3 (Sample 4). Lamellar and martensitic microstructures were not beneficial for the tribological response since they exhibited severe wear and very high COF values. The globular Ti alloy microstructure showed extremely high COF and wear under dry conditions. In general, water quenching was not a favorable treatment for tribological behavior. The lowest COF values and wear volumes were exhibited in the case of equiaxed microstructure

Eksperimentalno modeliranje i numerička FE analiza procesa izvlačenja sa stanjenjem čeličnih traka

This paper deals with analysis of steel strip ironing using experimental modelling and numerical FE simulation. Since both approaches are complementary to each other, numerous results were obtained that enable complete analysis of the processes within deformation zone. Device for modelling of strip ironing has been developed for experimental testing. Die cone angle, holding force, contact friction conditions on the die and the punch side were varied, due to easily replaceable working elements of the device. Friction coefficient values used in numerical FE simulations were determined based on measured values of forces on die and punch, as well as forming load on machine. Experimentally obtained results were confirmed by FE analysis that provided additional information about physics of the process itself within deformation zone. Presented research results point to coherent influences of process factors on tensile wall stress values, which represents key indicator for efficiency of forming, resulting in recommendations for efficient process management.Rad se bavi analizom procesa izvlačenja sa stanjenjem čelične trake, primjenom eksperimentalnog modeliranja i numeričkih FE simulacija. Kako su oba pristupa komplementarna, dobiveno je mnoštvo rezultata za sveobuhvatnu analizu procesa u deformacijskoj zoni. Za potrebe eksperimentalnog modeliranja razvijen je uređaj za modeliranje procesa izvlačenja sa stanjenjem trake. Zahvaljujući lako izmjenjivim radnim elementima uređaja, varirane su vrijednosti kuta matrice, sile držanja, uvjeti kontaktnog trenja na strani izvlakača i matrice. Vrijednosti faktora trenja, korištenih u numeričkim FE simulacijama su određene na osnovu izmjerenih vrijednosti sila na matrici i izvlakaču, kao i ukupne sile na stroju. Eksperimentalno dobiveni rezultati potvrđeni su numeričkom FE analizom, pri čemu je ona dala dodatne informacije o samoj fizici procesa u deformacijskoj zoni. Prikazani rezultati istraživanja ukazuju na spregnute utjecaje analiziranih faktora procesa na iznos rasteznog naprezanja u stijenki matrice, koji predstavlja ključni pokazatelj uspješnosti obrade, iz kojih proizlaze preporuke za uspješno upravljanje procesom

Kvalitet i mogućnost korišćenja silaže čičoke u ishrani goveda

Ensiling of Helianthus tuberosus L. was carried out in three terms/trials (15.8.2013 , 17.9.2013 and 7.10.2013). In the first trial Helianthus tuberosus L was ensiled in horizontal concrete silo trench, and in the second and third trial in a polyethylene foil. In the first and second trial dry matter content in Helianthus tuberosus L silage was 26.93:33.68%. Evaluated by DLG method silage trials had 41 and 44 points, and classified as class I or II, respectively. Silage pH values were 4.06:4.20. Content of lactic acid was 51.07:57.01%, total acetic acid 42.99:48.93%, withaut the presence of butyric acid. Consumption of silage in categories of heifers, beef cattle and dried milking cows was cca 3 kg. Better silage consumption was found in cattle categories fed a limited quantity of meals (heifers and dried milkingcows).Siliranje čičoke (Helianthus tuberosus L.) je obavljeno u tri roka (15.8.2013, 17.9.2013 i 7.10. 2013. U prvom roku čičoka je silirana je u horizontalnom betonskom silosu a u drugom i trećem u polietilenskoj foliji u obliku creva. U prvom i drugom roku siliranja suva materija silaže čičoke iznosila je 26,93 : 33,68%. Ocenom po DLG metodu silaže su imale 41 odnosno 44 poena i svrstane u I odnosno II klasu. Vrednost pH silaža iznosio je 4,06 : 4,20. Sadržaj mlečne kiseline iznosio je 51,07 : 57,01%, ukupne sirćetne kiseline 42,99 : 48,93 % dok prisustvo buterne kiseline nije utvrđeno. Konzumiranje silaže čičoke kod priplodnog podlatka goveda, junadi u tovu i zasušenih krava iznosilo je oko 3 kg u obrocima na bazi silaže biljke kukuruza, sena lucerke i koncentrata. Bolje konzumiranje silaže čičoke utvrđeno je kod goveda hranjenih ograničenim količinama obroka (podmladak i zasušene krave)

Lärarkontroll eller elevers självkontroll : En studie om vilken ledarstil gymnasieelever föredrar i klassrummet

Ledarstilar i klassrummet kan rangordnas på ett kontrollkontinuum med hög grad av lärarkontroll i den ena ändenoch hög grad av elevers självkontroll i den andra änden. Syftet med studien var att undersöka vilken ledarstil gymnasieelever på ett naturvetenskapsprogram föredrar i klassrummet. En enkätundersökning har genomförts med 31 elever i årskurs 1 och 24 elever i årskurs 3. Undersökningen visar att en majoritet av gymnasieleverna föredrar ledarstilar som präglas av lärarkontroll. Undersökningen visar också att eleverna överlag vill vara delaktiga i planeringen av undervisningen och bedömningen av kunskaper. Dock är de flesta av eleverna överens om att läraren är den som skapar och bibehåller ordningen i klassrummet. En möjlig förklaring till iakttagelsen är att eleverna vill utöva ett inflytande i klassrummet men saknar de färdigheter som krävs. En annan förklaring är att de är skeptiska till ett inflytande eftersom de inte vill riskera att bli dömda av klasskompisar eller läraren för sina åsikter och värderingar.I jämförelsen mellan elever i årskurs 1 och årskurs 3, föredrar de äldre eleverna i större utsträckning lärarkontroll i klassrummet. I jämförelsen mellan meritvärdesgrupper, föredrar de högpresterande eleverna i större utsträckning lärarkontroll i klassrummet än de låg och mellanpresterande. En trolig förklaring är att de äldre eleverna och de högpresterande eleverna inte vill ta det inflytande och ansvar som erbjuds eftersom det är både energikrävande och tar för mycket tid av den viktiga ämnesundervisningen

Molecular Dynamics Studies of Low-Energy Atom Impact Phenomena on Metal Surfaces during Crystal Growth

It is a well-known fact in the materials science community that the use of low-energy atom impacts during thin film deposition is an effective tool for altering the growth behavior and for increasing the crystallinity of the films. However, the manner in which the incident atoms affect the growth kinetics and surface morphology is quite complicated and still not fully understood. This provides a strong incentive for further investigations of the interaction among incident atoms and surface atoms on the atomic scale. These impact-induced energetic events are non-equilibrium, transient processes which complete in picoseconds. The only accessible technique today which permits direct observation of these events is molecular dynamics (MD) simulations. This thesis deals with MD simulations of low-energy atom impact phenomena on metal surfaces during crystal growth. Platinum is chosen as a model system given that it has seen extended use as a model surface over the past few decades, both in experiments and simulations. In MD, the classical equations of motion are solved numerically for a set of interacting atoms. The atomic interactions are calculated using the embedded atom method (EAM). The EAM is a semi-empirical, pair-functional interatomic potential based on density functional theory. This potential provides a physical picture that includes many-atom effects while retaining computational efficiency needed for larger systems. Single adatoms residing on a surface constitute the smallest possible clusters and are the fundamental components controlling nucleation kinetics. Small two-dimensional clusters on a surface are the result of nucleation and are present during the early stages of growth. These surface structures are chosen as targets in the simulations (papers I and II) to provide further knowledge of the atomistic processes which occur during deposition, to investigate at which impact energies the different kinetic pathways open up, and how they may affect growth behavior. Some of the events observed are adatom scattering, dimer formation, cluster disruption, formation of three-dimensional clusters, and residual vacancy formation. Given the knowledge obtained, papers III and IV deal with growth of several layers with the aim to study the underlying mechanisms responsible for altering growth behavior and how the overall intra- and interlayer atomic migration can be controlled by low-energy atom impacts.On the day of the defence date the status of article II was Accepted.</p

Lärarkontroll eller elevers självkontroll : En studie om vilken ledarstil gymnasieelever föredrar i klassrummet

Ledarstilar i klassrummet kan rangordnas på ett kontrollkontinuum med hög grad av lärarkontroll i den ena ändenoch hög grad av elevers självkontroll i den andra änden. Syftet med studien var att undersöka vilken ledarstil gymnasieelever på ett naturvetenskapsprogram föredrar i klassrummet. En enkätundersökning har genomförts med 31 elever i årskurs 1 och 24 elever i årskurs 3. Undersökningen visar att en majoritet av gymnasieleverna föredrar ledarstilar som präglas av lärarkontroll. Undersökningen visar också att eleverna överlag vill vara delaktiga i planeringen av undervisningen och bedömningen av kunskaper. Dock är de flesta av eleverna överens om att läraren är den som skapar och bibehåller ordningen i klassrummet. En möjlig förklaring till iakttagelsen är att eleverna vill utöva ett inflytande i klassrummet men saknar de färdigheter som krävs. En annan förklaring är att de är skeptiska till ett inflytande eftersom de inte vill riskera att bli dömda av klasskompisar eller läraren för sina åsikter och värderingar.I jämförelsen mellan elever i årskurs 1 och årskurs 3, föredrar de äldre eleverna i större utsträckning lärarkontroll i klassrummet. I jämförelsen mellan meritvärdesgrupper, föredrar de högpresterande eleverna i större utsträckning lärarkontroll i klassrummet än de låg och mellanpresterande. En trolig förklaring är att de äldre eleverna och de högpresterande eleverna inte vill ta det inflytande och ansvar som erbjuds eftersom det är både energikrävande och tar för mycket tid av den viktiga ämnesundervisningen

Effects of feeding buffering mineral mixture on subacute rumen acidosis and some production traits in dairy cows

This trial was designed in order to evaluate the incidence of subacute rumen acidosis (SARA) during early lactation and to investigate the possibilities for its prevention by use of a buffering mineral mixture. On the beginning of the trial it was found that the pH value of rumen fluid in 4 animals was lower than normal (pH < 6.0) and that 20% of animals have had SARA. The control and the experimental group of cows were fed the same meal with exception of concentrated feed which in the experimental group contained the mineral mix with buffering activity in amount of 1%. Continuous addition of buffering mineral mixture in the amount of 1% in concentrated feed for early lactation cows successfully prevents SARA formation and leads to increased milk production, as well as increased milk fat and protein content

Experimental study and analytical model of shear thinning in 3d bioprinting of gelatin

© 2020 Published by Faculty of Engineering. This paper presented extrusion-based 3D bioprinting of gelatin hydrogel and optimisation of material properties and process parameters, in order to improve printability of hydrogel. Gelatin hydrogel was prepared by mixing it with water in concentration of 13.04 wt%. Dimensional accuracy of the bioprinting was studied and significant changes in comparison with designed geometry were noted. Gelatin hydrogel made only with water showed inadequate thixotropy for extrusion based bioprinting and poor mechanical properties of the printed sample, and needs additional constituents to enable good printability with satisfying dimensional accuracy. We presented parameter optimisation index (POI), shear thinning model and friction factor of gelatin hydrogel by using analytical approach. Friction factor of the gelatin hydrogel during bioprinting was 0.268 10-5. Analytical models of shear thinning and friction factor were in consistence with experimental data, and indicated that such approach can be used in optimisation of bioprinting parameters and material properties