Kapljični model polimernih micel

We present a theoretical study of the liquid-drop model, a novel coarse-grained approach which describes the micromechanics of soft nanocolloidal particles by modelling them as compressible liquid drops. The liquid-drop free energy consists of a bulk and a surface term, which allows one to describe particles with a wide range of compressibilities and one or more types of contacts with their environment, either with other drops or with solvent. Using the cell approximation, we investigate the phase diagrams of the model in both three and two dimensions as well as the appearance of layered quasicrystals in deformable nanoparticles.Disertacija združuje več teoretičnih raziskav kapljičnega modela, novega efektivnega opisa mikromehaničnih lastnosti mehkih nanokoloidnih delcev, v katerem te delce predstavimo kot stisljive kapljice. Prosta energija kapljičnega modela sestoji iz prostorninskega in iz površinskega člena, s čimer lahko zajamemo tako zelo stisljive kot domala nestisljive delce ter eno ali več vrst stikov delcev z okolico bodisi z drugimi delci bodisi s topilom. V okviru celičnega približka izračunamo fazne diagrame modela tako v dveh kot v treh razsežnostih kot tudi plastovite kvazikristale deformabilnih nanodelcev

The influence of temperature, disinfection and water softening of drinking water on the multiplication of Legionella pneumophila

The influence of temperature, disinfectant and water softener for drinking water preparation on the bacterial growth of Legionella pneumophila was examined.The optimal temperature for bacterial growth was 36 °C. At the incubation temperature of 15 °C the multiplying of bacteria slowed down, as confirmed by the bacteriostatic effect of this temperature. The number of bacteria was after the first 24 h of incubation at 55 °C reduced by more than 6 log in comparison to the culture at 36 °C. After 10 minutes of exposure to the disinfectant dichloroisocyanuric acid, the number of bacteria in the culture decreased for 1.4 log CFU mL-1, followed by an intensive growth immediately after the disinfectant degradation. The number of bacteria was up to 72 hours incubation even higher than in the control sample without a disinfectant, and then the number in both samples equalled at approximately 7.3 log CFU mL-1. Sodium polyphosphate used as a water softener stimulated the bacterial growth. The largest difference in growth was observed after 72 h of incubation, which was 1.9 log CFU mL-1 higher in samples with sodium polyphosphate in comparison to those without the softener

Personal hygiene awareness among food handlers

In the globalization and rapid industrial development times food safety assurance is one of the basic conditions for protection of public health. For this purpose knowledge and awareness of personal hygiene among food handlers were determined in one of the middle-sized meat processing plants. It was found out that food handlers are aware of personal hygiene, but do not always practice it. Were observed problems in inter – social relations and communication difficulties at all levels, which can influence on quality of work performed and consequently on food safety assurance. Awareness of importance of good hygiene practice is based upon sense and is not uniformed. Periodicall, thematicall and methodologicall adapted trainings are crucial for food safety

Hybrid-mixed shell quadrilateral that allows for large solution steps and is low-sensitive to mesh distortion

We compare three nearly optimal quadrilateral finite elements for geometrically exact inextensible-director shell model. Two of them are revisited and one is novel. The assumed natural strain (ANS) element of Ko et al. (Comput Struct 185:1-14, 2017) shows low sensitivity to mesh distortion and excellent convergence behavior for most types of shell problems. The Hu Washizu element with ANS shear strains of Wagner and Gruttmann (Int J Numer Methods Eng, 64:635-666, 2005) allows for large solution steps and is computationally fast. However, both formulations have undesirable weak spots, which we clearly identify by a comprehensive set of numerical examples. We show that a straightforward combination of both formulations results in a novel element that synergizes the positive features and eliminates the weak spots of its predecessors

Antioksidativna učinkovitost sinapinske kisline in njenih derivatov v modelnih lipidnih sistemih

The effectiveness of sinapic acid and its derivatives varied with the test system, the type of free radicals and the mechanism of antioxidant activity. It was shown that early response parameters of free radical scavenging are adequate to evaluate differences between antioxidants with comparable endpoint (steady-state) activity. Among selected compounds syringic acid and sinapic acid showed the highest DPPH˙ and O2˙– scavenging activities (determined at steady-state) and the highest ability to inhibit lipid peroxidation in oil. Sinapic acid esters had the highest activities in oil-in-water emulsion and liposome suspension, and ethyl sinapate and propyl sinapate, furthermore, proved to be excellent ˙OH-scavengers. These esters, which were the most lipophilic, had the greatest effects on liposome bilayer thermal and enthalpic destabilisation of the gel state and increased the ordering of the liquid state of the lipids. This dual effect on the lipid bilayer might suggest that the esters initiate the formation of nanodomains with reduced fluidity that can capture hydroperoxides and thus inhibit lipid peroxidation. In the oleogel, the level of inhibition for the more polar compounds, sinapic acid, syringic acid and syringaldehyde, and less polar, 4-vinylsyringol and butyl sinapate, was at the same level, indicating the possible interactions of these less polar compounds with the oil structuring agent in oleogel. This research thus opened a new approach: the possibility of incorporating lipophilic antioxidants to prolong the oxidative stability of oleogel based products. It was shown that white mustard seeds provide excellent source of raw material for the recovery of value-added antioxidant compounds that are effective in preventing lipid peroxidation in systems such as oil and oleogel.Učinkovitost sinapinske kisline in njenih derivatov se razlikuje glede na testni sistem, vrsto prostih radikalov in mehanizem antioksidativnega delovanja. Pokazali smo, da so parametri zgodnjega odziva v lovljenju prostih radikalov ustrezni za ocenjevanje razlik med antioksidanti s primerljivo aktivnostjo v končni točki (v stanju ravnotežja). Med izbranimi spojinami sta siringinska kislina in sinapinska kislina pokazali največjo sposobnost lovljenja O2˙– in DPPH˙radikalov (določeno v stanju ravnotežja) in največjo sposobnost zaviranja peroksidacije lipidov v olju. Estri sinapinske kisline so imeli najvišjo aktivnost v emulziji olja-v-vodi in suspenziji liposomovetil sinapat in propil sinapat pa sta se izkazali za odlična lovilca ˙OH radikalov. Estri, ki so najbolj lipofilni, imajo največji učinek na termično in entalpijsko destabilizacijo stanja gela liposomskega lipidnega dvosloja in povečajo urejenost v tekočem stanju lipidov. Ta dvojni učinek na lipidni dvosloj bi lahko pomenil, da estri sprožijo tvorbo nanodomen z zmanjšano fluidnostjo, ki ujamejo hidroperokside in s tem zavirajo peroksidacijo lipidov. V oleogelu je bila stopnja inhibicije za bolj polarne spojine, sinapinsko kislino, siringinsko kislino in siringaldehid, na isti ravni kot za, 4-vinilsiringol in butil sinapat, kar je pokazalo na možne interakcije teh manj polarnih spojin s sredstvom za strukturiranje olja v oleogel. Ta raziskava je tako odprla nov pristop: možnost vključitve lipofilnih antioksidantov za podaljšanje oksidativne stabilnosti izdelkov na osnovi oleogelov. Pokazali smo, da predstavljajo semena bele gorčice surovino z dodano vrednostjo za pridobivanje antioksidativnih spojin, ki so učinkovite pri preprečevanju peroksidacije lipidov v sistemih, kot sta olje in oleogel

Vibrotactile feedback in a haptic device for spatial guidance of an aircraft

Po statističnih izračunih EASA letnih pregledov varnosti, je izguba nadzora nad letalom eden izmed glavnih razlogov, ki privedejo do letalske nesrče. Razne naprave in konstrukcijski dodatki za opozarjanje na porušitev vzgona so pogosto uporabljeni v modernih letalih. Njihova glavna naloga je opozarjanje pilota na bližajočo se porušitev vzgona, njeno preprečevanje ali zakasnitev. V večini se pri tem osredotočajo na usmerjanje pozornosti pilota in ne dajejo prostorskih ali reakcijskih smernic. Cilj je razviti napravo, ki ne bi le preprečila ali le opozorila pilota, da se letalo približuje nevarnemu ali neučinkovitemu režimu leta, temveč da bi ga vodila do pravilnega reševanja oz. izhoda. Diplomska naloga zajema preiskavo, kodiranje in vrednotenje metod haptičnega vodenja, ki bodo uporabljene pri nadaljnjem razvoju omenjene naprave. Najprej so preučene obstoječe rešitve in literatura na področjih haptičnega čuta in vibracijske povratne zveze. Eksperimentalno preizkuševališče je sestavljeno iz igralniške palice, dveh vibracijskih motorjev in arduino MEGA mikrokrmilnika. Na podlagi preučenih podobnih rešitev in literature sta bila določena dva parametra vodenja, na katere je možno vplivati: trajanje pulza in ritem vibracij. Način kodiranja informacij o razdalji med dejanskim položajem naprave in njenim želenim končnim položajem z vibracijsko povratno zvezo je, glede na vpliv na omenjena parametra, razvit v treh različnih kombinacijah: »ritem«, »trajanje«, ter »ritem in trajanje«. Izpeljan je test z namenom preučitve osnovne intuitivnosti treh razvitih metod. Rezultati testa naj bi pripomogli k nadaljnemu primerjalnemu vrednotenju. Osnovna naloga vsake metode vključuje sledenje vibracijskim povratnim zvezam do naključno določenega položaja igralniške palice ter ohranjanje tega položaja do naslednjega novo-določenega. Poskusni osebek mora za vsako metodo izvesti en poskus. Vsak poskus vključuje sledenje ter držanje 21 naključno določenih položajev. Med tem mora poskusni osebek jasno izražati svoje zaznavanje vibracij in občutke povezane z vibracijsko povratno zvezo vsake metode. Glede na rezultate, je metoda »ritem« izključena, saj je osebek z njo dosegel manjšo natančnost in ob tem tudi pripomnil, da je nejasna in begajoča, zlasti na intervalu v neposredni bližini položaja, kjer so za tako majhne razdalje dosežene hitrosti roke relativno zelo visoke. Z namenom, da bi se pri uporabi metod povišalo doseženo natančnost, je obema obstoječima metodama dodana povratna vibracijska zveza, poimenovana nasprotna vibracija. Ta naj bi se izvršila le, ko je želen položaj prvič dosežen. Na tak način naj bi opozorila poskusni osebek o doseženem cilju in pri poskusu držanja položaja preprečila izvajanje večjih napak. Obe metodi z obema verzijama, z in brez nasprotne vibracije, sta preizkušeni in ovrednoteni. Preizkus je potekal na 22 poskusnih osebkih, 16 moškega spola ter 6 ženskega, med 21. in 27. letom starosti. Ti so bili naključno razdeljeni v dve skupini – 11 osebkov za vsako metodo – zato da ne bi prišlo do izkrivljanja rezultatov meritev učnega procesa zaradi podobnosti metod. Vsak osebek je moral preizkus opraviti v treh delih: učni del, ki je vključeval sledenje in držanje 30 položajev in katerega meritve so bile primerjane z meritvami glavnega dela ter uporabljene za ovrednotenje vpliva metode na učljivostglavni del, ki je ravno tako vključeval sledenje in držanje 30 položajev in katerega meritve obeh metod so bile primerjane med seboj za ovrednotenje vpliva metode na natančnostter del nasprotne vibracije, ki je vključeval enako nalogo kot ostala dva dela in katerega meritve so bile primerjane z meritvami glavnega dela ter uporabljene za ovrednotenje uporabnosti nasprotne vibracije. Vsi osebki so morali ob tem izraziti svoja zaznavanja in občutke. Izmerjeni podatki so bili ovrednoteni na bazi preizkušanja statističnih hipotez. Ovrednoteni so bili vpliv metod na natančnost, vpliv metod na učljivost in uporabnost nasprotne vibracije. Na podlagi enostranske t-test analize dveh neodvisnih vzorcev s stopnjo značilnosti 0,05, je metoda »trajanje« dosegla pomenljivo večji vpliv na natančnost v primeru vseh treh merjenih parametrov (p vrednosti 0,00250,005080,000003). Na podlagi enostranske t-test analize dveh odvisnih vzorcev (glavni del in del nasprotne vibracije) metode »trajanje« s stopnjo značilnosti 0,05, v primeru vseh treh merjenih parametrov, nasprotna vibracija ni dosegla pomenljivega vpliva na natančnost (p vrednosti 0,2640,3150,283). Nasprotno je na podlagi enostranske t-test analize dveh odvisnih vzorcev (glavni del in del nasprotne vibracije) metode »ritem in trajanje« s stopnjo značilnosti 0,05, v primeru vseh treh merjenih parametrov, nasprotna vibracija dosegla pomenljivo pomanjšanje natančnosti (p vrednosti 0,00000120,0000130,0097). Poleg tega je 18 osebkov od 22 izjavilo, da jih je nasprotna vibracija močno zmedla zaradi nenadne povratne zveze, ki je pri njih vzbudila nesigurnost, dodatno instinktivno premikanje roke in občutek pomanjšanja natačnosti. Na koncu je bil ovrednoten še vpliv na učljivost na podlagi enostranskih t-test analiz dveh odvisnih vzorcev (učni del in glavni del) s stopnjo značilnosti 0,05 dveh parametrov (čas držanja in potrebni čas za sledenje do položaja) za vsak osebek posamezno. Le 4 osebki metode »trajanje« so dosegli pomenljivo izboljšavo obeh parametrov, medtem ko je pri metodi »ritem in trajanje« pomeljivo izboljšavo za čas držanja doseglo 9 osebkov in za potrebni čas za sledenje do položaja 7 osebkov.Encoding and evaluation of haptic guiding methods with vibrotactile feedback are made as part of a project, the aim of which is designing a device that would help the pilot achieve a greater precision in-flight. Different kinds of stall warning devices and structural additions already exist that focus on attentional guidance, but do not consider spatial and movement guidance. The parameters, which can be manipulated, are defined and studied leading to three different combinations: »Only Duration« (OD), »Only Rhythm« (OR) and »Rhythm & Duration« (R&D). A pilot test was conducted to define their basic intuitiveness, narrowing the guiding methods down to two – OD and R&D. An additional vibration, named »vibration alert« (VA), is added to both methods with the aim of increasing the accuracy. These two methods are tested with a series of hypothesis tests to evaluate their learnability, accuracy, and intuitiveness. Based on the results the OD method is found out to be significantly more accurate than the R&D method. The additional vibration led to no significant improvements for the OD method and a significant decrease in the accuracy of the R&D method. Bigger improvement is achieved using the R&D method compared to the OD method

Raziskave ultrahitrih procesov v koreliranih snoveh s tunelskim vrstičnim mikroskopom

This thesis is focused on combining the atomically resolved microscopic picture with the ultrafast sub picosecond picture of laser induced phase transitions in 1T-TaS2. The combination of scanning tunneling microscopy (STM) and pump-probe measurements, gives insight not only into the microscopic ordering and topological nature of different laser induced states in 1T-TaS2, but also into the conditions at which they are formed and the timescales at which they appear. The layered transition metal dichalcogenide 1T-TaS2 has undergone a recent resurgence of interest with the discovery of a stable hidden state, which can be induced by an ultrashort laser or electrical pulse. Since the transition is fast, the material became a very promising candidate for future cryogenic memory elements. I performed multiple excitation intensity dependent switching experiments at different temperatures in order to construct a phase diagram of photoinduced states in 1T-TaS2. It turns out that optical switching to the hidden state is very robust, while on the other hand switching to the other observed states cannot be controllably reproduced using an 800 nm laser. The threshold fluence for switching to the hidden state appears to be temperature independent, suggesting that only the density of the photoinduced carriers is important for the transition. Other photoinduced states such as the amorphous state and states with different chiralities seem to appear more randomly. At high laser powers, I discovered a novel kind of laser induced transformation that is a single layer polytype transformation from 1T to 1H polytype, where local heating and fast quench play a crucial role in formation of the new state. The polytype transformed layer shows a phase transition between the stripe phase and a network of hexagonal vertices, as seen with STM, which show interesting topological nature. I also examined the domain walls between the domains of different chiralities in 1T-TaS2, which appear to have a non-trivial structure. In order to combine the ultrafast measurements with atomically resolved STM scans, I built a prototype THz gated STM. I built and characterized several THz single cycle pulse sources and used them to excite the STM tip. I observed up to 20 pA of rectified THz current, which is expected enough to observe changes in time resolved measurements. The device was not finalized during my research work, but I am nevertheless showing the interesting and helpful experimental observations in order to make the future optimization of the THz resolved STM easier.Doktorsko delo je posvečeno povezavi med atomsko ločljivimi mikrokopskimi slikami in ultrahitrimi pod pikosekundnimi meritvami lasersko vzbujenih faznih prehodov v 1T-TaS2. Kombinacija vrstične tunelske mikroskopije (STM) in vzbuditveno testne tehnike nam da vpogled ne le v mikroskopsko sliko urejanja in topološko naravo različnih lasersko vzbujenih stanj, temveč tudi v pogoje pod katerimi se ta stanja pojavijo in v časovno skalo na kateri se oblikujejo. 1T-TaS2 je plastoviti dihalkogenid prehodnih kovin, ki je vzbudil veliko zanimanje z odkritjem stabilnega skritega stanja, ki ga lahko vzbudimo z ultrahitrim laserskim ali električnim sunkom. Ker je prehod hiter, je 1T-TaS2 postal zelo dober kandidat za ultrahitre nizkotemperaturne spominske elemente prihodnosti. Izvedel sem več meritev, kjer sem spreminjal moč in fluenco laserskega snopa pri različnih temperaturah z namenom sestaviti fazni diagram fotoinduciranih stanj v 1T-TaS2. Izkaže se, da je optični preklop v skrito stanje zelo robusten in da je mejna fluenca za preklop enaka pri vseh temperaturah. Po drugi strani pa je preklop med ostalimi stanji težko ponovljiv pri uporabi laserja z valovno dolžino 800 nm. Tako se amorfno stanje in stanja z domenami različnih kiralnosti pri preklapljanju pojavljajo naključno. Pri uporabi visokih moči laserja sem opazil novo vrsto laserske transformacije v kristalu, in sicer gre za politipno transformacijo vrhnje plasti materiala iz 1T v 1H politip, kjer ključno vlogo igra lokalno segrevanje in hitro ohlajanje. Na transformirani površini lahko opazujemo fazni prehod med fazama s črtami in trikotno mrežo, ki kažeta zanimive topološke lastnosti. Podrobneje sem preučil tudi domenske stene med domenami različne kiralnosti, ki nimajo trivialne strukture. Z namenom združiti ultrahitre meritve z atomsko ločljivimi STM slikami sem sestavil teraherčno (THz) prožen STM. Sestavil in karakteriziral sem nekaj virov ultrahitrih teraherčnih sunkov in jih uporabil za vzbujanje konice tunelskega mikroskopa. Opazil sem do 20 pA usmerjenega THz toka, kar je dovolj za opazovanje sprememb v časovno ločljivih meritvah. Naprava v času mojega dela ni bila popolnoma dokončana. Izsledki so kljub temu predstavljeni kot pomoč pri nadaljnji izgradnji in optimizaciji naprave

Public services performance: an extended framework and empirical assessment across the enlarged EU

Performance of the public sector is at the core of long-term wealth creation and welfare improvement. Yet, its measurement remains inadequate and flawed with data deficiency. The paper proposes an extended framework for the assessment of public services performance that accounts for long-term impacts on welfare and empirically evaluates it across 25 European countries on the basis of a wide set of proxy indicators. We relate the performance scores to input costs indices and propose a coherent typology of countries that correspond to the patterns of economic effectiveness of public services. The empirical analysis reveals that due to differences in input costs across the enlarged EU the economic effectiveness of public services varies to a much larger extent than the performance, with some relatively large-size governments (Sweden, Denmark, Austria) being the most effective ones

Old world megadroughts and pluvials during the common era

Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other “Old World” climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the “Old World Drought Atlas” (OWDA), a set of year-to-year maps of tree-ring reconstructed summer wetness and dryness over Europe and the Mediterranean Basin during the Common Era. The OWDA matches historical accounts of severe drought and wetness with a spatial completeness not previously available. In addition, megadroughts reconstructed over north-central Europe in the 11th and mid-15th centuries reinforce other evidence from North America and Asia that droughts were more severe, extensive, and prolonged over Northern Hemisphere land areas before the 20th century, with an inadequate understanding of their causes. The OWDA provides new data to determine the causes of Old World drought and wetness and attribute past climate variability to forced and/or internal variability

Generalization analysis of semantic segmentation with deep filter banks

Mobilni robotski sistemi, ki so sposobni avtonomne navigacije v nestrukturiranih okoljih, so odvisni od njihovih modulih vida, da bi lahko bili sposobni se navigirati čez okolje. Moduli vida priskrbijo percepcijo okolice, in pogosto morajo identificirati določene predmete, ki nas zanimajo. Identifikacija nastane tako da določene segmente slik klasificira v enem izmed vnaprej naučenih razredov. Na področju računalniškega vida obstaja veliko postopkov semantične segmentacije, ki poročajo izjemne rezultate. Vendar so ti postopki naučeni samo na določenih podatkovnih zbirkah, ki niso nujno medsebojno odvisni z različnimi prizorišči, ki jih mobilni robot opazi. Da bi preverili sposobnost podatkovne zbirke prenesti svoje znanje na novi domeni bomo preiskovali kvaliteto generalizacije njenih razredov. Preverili bomo prenos znanja specifičnega postopka semantične segmentacije, ki smo ga prilagodili našim potrebam.Mobile robotic systems capable of autonomous navigation in non-structured environments depend on their vision module in order to safely navigate through the environment. The vision module provides perception of the surrounding area and it is often required to identify particular objects of interest, which is done by classifying image segments into pre-learned semantic classes. There are many methods which provide remarkable semantic segmentation results, but unfortunately only on specific datasets, which are not necessarily correlated to the scenes observed by a mobile robot. To verify the dataset\u27s capability of transferring knowledge to a new domain we explore how well it generalises its classes. We examine the transfer of knowledge on a specific semantic segmentation method, which we adjust to best fit our needs