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1.
PREVENTION AND MANAGEMENT OF LEGIONELLA SPP. SPREAD IN HOSPITAL WATER SYSTEM (ESTABLISHING AN EFFECTIVE SYSTEM WITHOUT USING CHEMICALS IN UNIVERSITY CLINIC OF RESPIRATORY AND ALLERGIC DISEASES GOLNIK)
Mojca Novak, 2016, magistrsko delo

Opis: The hospital water system can be a causative agent for acquiring hospital-acquired infection. Many microorganisms can be detected in potable water and one of this is Legionella spp. These bacteria live also in nature, but are usually present in low numbers. When entering into the buildings and their water supply, Legionella finds ideal conditions to multiply, especially if this systems are extensive and old. To control the conditions in the levels that cannot harm humans, many procedures – physical and chemical – have been established. All of them have advantages as well as limitations. According to these facts, in University Clinic of Respiratory and Allergic Diseases Golnik we tried to reestablish the protocols that would keep us on the safe side and be environmentally and health friendly as well. We have been trying to use the protocol without added chemicals – just with maintaining proper temperatures, heat disinfection and flushing for many years now. With this study we wanted to extend our knowledge of our hospital water system, so we intensified the sampling and introduced extended measures. We found out that the presence of Legionella in water system is connected to moderate temperatures and it is present more frequently in high risk zones (inappropriate temperatures, dead legs, water stagnation). With constant measures, the Legionella can be controlled but not eradicated. To contain it on a safe level, the group of experts must work together and introduce procedures that will provide safe environment for the patients and employees.
Najdeno v: ključnih besedah
Ključne besede: Legionella spp., hospital water system, prevention, temperature, flushing.
Objavljeno: 30.09.2016; Ogledov: 1902; Prenosov: 134
.pdf Polno besedilo (2,81 MB)

2.
Pursuing the stabilisation of crystalline nanostructured magnetic manganites through a green low temperature hydrothermal synthesis
Paolo Dolcet, Arianna Minelli, Stefano Diodati, Sandra Gardonio, Claudia Innocenti, Denis Badocco, Stefano Gialanella, Paolo Pastore, Luciano Pandolfo, Andrea Caneschi, Angela Trapanati, Silvia Gross, 2017, izvirni znanstveni članek

Opis: A quick, easy and green water-based synthesis protocol involving coprecipitation of oxalates combined with hydrothermal treatment resulted in the crystallisation of nanostructured manganites at a relatively low temperature (180 °C). The subcritical hydrothermal approach was shown to play a key role in stabilising phases which are generally achieved at much higher temperatures and under harsher conditions, thus disclosing an exciting alternative for their synthesis. Through this mild wet chemistry approach, the compounds CuMnO2, ZnMn2O4 and ZnMnO3 were synthesised as nanocrystalline powders. Noticeably, the optimised route proved to be effective in stabilising the exotic polymorph cubic spinel ZnMnO3 in pure form. This is particularly notable, as very few records concerning this compound are available in the literature. The compounds were fully characterised from compositional, structural, morphological and magnetic points of view.
Najdeno v: ključnih besedah
Ključne besede: nanostructured manganites, low temperature wet chemistry synthesis
Objavljeno: 28.03.2017; Ogledov: 959; Prenosov: 0
.pdf Polno besedilo (1,59 MB)

3.
Transparent titania-zirconia thin films for self-cleaning and photocatalytic application
Vlasta Brezová, Kandalam Ramanujachary, Nives Vodišek, Urška Lavrenčič Štangar, 2016, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: Thin films were prepared by sol-gel process, where different amount of zirconia were added to titania. Photocatalytic activity of thin films was measured by two methods i) determination of degradation ration of methyl stearate with measuring the contact angle and ii) formation of hydroxyterephthalic acid was measured by spectrofluorometer. Prepared samples were characterized by UV-Vis spectrophotometer, SEM, XRD, FT-IR ATR, and BET. The result of measurements of photocatalytic activity shows that the highest activity has a sample without addition of zirconia, but mechanical stability of that sample is worse.
Najdeno v: ključnih besedah
Ključne besede: photocatalysis, ZrO2/ TiO2, thin films, self-cleaning, low-temperature, sol-gel process
Objavljeno: 14.03.2017; Ogledov: 1273; Prenosov: 77
.pdf Polno besedilo (462,52 KB)

4.
PHOTO-EXCITATION ENERGY INFLUENCE ON THE PHOTOCONDUCTIVITY OF ORGANIC SEMICONDUCTORS
Nadiia Pastukhova, 2018, doktorska disertacija

Opis: In this work, we experimentally studied the influence of photoexcitation energy influence on the charge transport in organic semiconductors. Organic semiconductors were small molecules like corannulene, perylene and pentacene derivatives, polymers such as polythiophene and benzothiophene derivatives, and graphene, along with combinations of these materials in heterojunctions or composites. The first part of this study is focused on the photoexcitation energy influence on the transient photoconductivity of non-crystalline curved π-conjugated corannulene layers. The enhanced photoconductivity, in the energy range where optical absorption is absent, is deduced from theoretical predictions of corannulene gas-phase excited state spectra. Theoretical analysis reveals a consistent contribution involving transitions to Super Atomic Molecular Orbitals (SAMOs), a unique set of diffuse orbitals typical of curved π-conjugated molecules. More, the photoconductivity of the curved corannulene was compared to the π-conjugated planar N,N′-1H,1H- perfluorobutyldicyanoperylene-carboxydi-imide (PDIF-CN2), where the photoexcitation energy dependence of photocurrent closely follows the optical absorption spectrum. We next characterized charge transport in poly(3-hexylthiophene) (P3HT) layers deposited from solution. Our results indicate that time-of-flight (TOF) mobility depends on the photoexcitation energy. It is 0.4× 10 −3 cm 2 /Vs at 2.3 eV (530 nm) and doubles at 4.8 eV (260 nm). TOF mobility was compared to field-effect (FET) mobility of P3HT field-effect transistors (OFETs). The FET mobility was similar to the 2.3 eV excitation TOF mobility. In order to improve charge mobility, graphene nanoparticles were blended within a P3HT solution before the deposition. We found that the mobility significantly improves upon the addition of graphene nanoparticles of a weight ratio as low as 0.2 %. FET mobility increases with graphene concentration up to a value of 2.3× 10 −2 cm 2 /Vs at 3.2 %. The results demonstrate that phase segregation starts to influence charge transport at graphene concentration of 0.8 % and above. Hence, the graphene cannot form a bridged conduction channel between electrodes, which would cancel the semiconducting effect of the polymer composite. An alternative approach to enhance mobility is to optimize the molecular ordering of organic semiconductors. For that purpose, we studied an innovative nanomesh device. Free-standing nanomesh devices were used to form nanojunctions of N,N′- iiDioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) nanowires and crystalline bis(triisopropylsilylethinyl)pentacene (TIPS-PEN). We characterized the photocurrent response time of this novel nanomesh scaffold device. The photoresponse time depends on the photon energy. It is between 4.5 − 5.6 ns at 500 nm excitation wavelength and between 6.7 − 7.7 ns at 700 nm excitation wavelength. In addition, we found that thermal annealing reduces charge carrier trapping in crystalline nanowires. This confirms that the structural defects are crucial to obtaining high photon-to-charge conversion efficiency and subsequent transport from pn junction in heterostructured materials. Structural defects also influence the power conversion efficiency of organic heterostructured photovoltaics (OPVs). Anticipating that polymers with different backbone lengths produce different level of structural defects, we examined charge transport dependence on the molecular weight of poly[4,8-bis(5-(2- ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2- ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl] (PTB7-Th) from 50 kDa to 300 kDa. We found p-type hopping transport in PTB7-Th, characterized by 0.1 – 3× 10 −2 cm 2 /Vs mobility, which increases with temperature and electric field. The polymer molecular weight exhibits a non-trivial influence on charge transport. FET mobility in the saturation regime increases with molecular weight. A similar trend is observed in TOF mobility and FET mobility in the linear regime, except for the 100kDa polymer, which manifests in the highest mobility due to reduced charge trapping. The lowest trapping at the dielectric interface of OFET is observed at 200 kDa. In addition, the 200 kDa polymer exhibits the lowest activation energy of the charge transport. Although the 100 kDa polymer indicates the highest mobility, OPVs using the 200 kDa polymer exhibit the best performance in terms of power conversion efficiency.
Najdeno v: ključnih besedah
Ključne besede: organic semiconductors, optical absorption spectroscopy, time-of-flight photoconductivity, transient photocurrent spectroscopy, organic thin film transistors, atomic force microscopy, superatomic molecular orbitals, pn heterojunction, organic nanowires, graphene, composites, charge mobility, charge trapping, temperature dependence, photodetector, photovoltaic, solar cell, organic electronics
Objavljeno: 08.10.2018; Ogledov: 371; Prenosov: 23
.pdf Polno besedilo (4,56 MB)

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