Nuclear power before and after the disaster of Fukushima Daiichi

Tato bakalářská práce pojednává o havárii v jaderné elektrárně Fukušima Daiči. Jsou zde popsány příčiny a následky této havárie a vývoj jaderné energetiky před touto havárií a po ní. Jaderná havárie ve Fukušimě Daiči je zde také srovnána s havárií v jaderné elektrárně Černobyl. Závěr této práce je věnován technicko-ekonomické studii pro úplné odstoupení České republiky od jaderné energetiky.This bachelor’s thesis is written about accident in Fukushima Daiichi power plant. There are described causes and consequences of this accident and also status of nuclear energy before and after this accident. The disaster at Fukushima Daiichi is compared with the disaster at Cernobyl nuclear power plant in this work too. At the end of this thesis is written technical and economical study for phase out of nuclear energy in the Czech Republic.

Tree-ring width and variation of wood density in Fraxinus excelsior L. and Quercus robur L. growing in floodplain forests

Oven-dry wood density variations are reported for European ash (Fraxinus excelsior L.) and English oak (Quercus robur L.) trees growing in floodplain mixed forests in South Moravia, Czech Republic. Two sites with different water regime conditions were selected along the Dyje (site A) and the Morava (site B) Rivers. In total, 20 dominant, healthy trees were chosen to determine the tree-ring structure and the oven-dry wood density (ρ0) along the radius of the stem cross section. The tree-ring width followed the common trend of a general decline as the trees aged. After removing the age influence, significant differences were observed in the tree-ring structure, recorded several years after water regime treatments. The European ash and the English oak ρ0 were found to be 677.3 kgBULLET OPERATORm-3 and 618.2 kgBULLET OPERATORm-3, respectively, significantly differing between the sites, for both species. High variability of ρ0 was also noticed along the stem radius in both species and sites.O

Heterogeneous liposome assemblies: one goal, different paths

Liposomes are nowadays almost routinely used as encapsulating agents for various drug molecules1. Classical mode of operation of such a system is the passive release of encapsulated drug from lonesome individual liposomes. Possibilities to control the release via pH, temperature or external stimulus such as magnetic field or sonication have already been examined, but mostly for individual liposomes. The pathway leading to creation and use of dense liposome aggregates as either the encapsulating agent or the chemical microreactor remains however quite unexplored. Our group successfully tested the concept of alginate microparticles containing both liposomes and magnetic nanoparticles2. Further work addressing their size and encapsulation efficiency is now underway. As a next system we have examined the formation of liposome aggregates induced by the high salt concentration. We have prepared aggregates with sizes varying from hundreds of nanometers to tenths of micrometers. We varied salt concentration, aggregation time and eventually we have used the capping polymer to obtain desired size and morphology of aggregates. Even more sophisticated strategy is to use the antisense DNA amphiphiles as anchors for controlled assembly of different liposome populations. We have tested the ability of some of these anchors to form liposome assemblies. Finally we linked liposomes together using the electrostatic interaction between charged lipid vesicules and polyelectrolyte3. We used alginate, chitosan or poly-L-lysine as charged biopolymers and studied encapsulation and release of model drug to/from aggregates that contained also iron oxide nanoparticles. These were included in the assembly and influenced the size and morphology of the assembly as well as its encapsulation/release characteristics. Please click Additional Files below to see the full abstract

Measurement methods and variability assessment of the Norway spruce total leaf area: implications for remote sensing

Estimation of total leaf area (LAT) is important to express biochemical properties in plant ecology and remote sensing studies. A measurement of LAT is easy in broadleaf species, but it remains challenging in coniferous canopies. We proposed a new geometrical model to estimate Norway spruce LAT and compared its accuracy with other five published methods. Further, we assessed variability of the total to projected leaf area conversion factor (CF) within a crown and examined its implications for remotely sensed estimates of leaf chlorophyll content (C ab). We measured morphological and biochemical properties of three most recent needle age classes in three vertical canopy layers of a 30 and 100-year-old spruce stands. Newly introduced geometrical model and the parallelepiped model predicted spruce LAT with an error <5% of the average needle LAT, whereas two models based on an elliptic approximation of a needle shape underestimated LAT by up to 60%. The total to projected leaf area conversion factor varied from 2.5 for shaded to 3.9 for sun exposed needles and remained invariant with needle age class and forest stand age. Erroneous estimation of an average crown CF by 0.2 introduced an error of 2-3μgcm−2 into the crown averaged C ab content. In our study, this error represents 10-15% of observed crown averaged C ab range (33-53μgcm−2). Our results demonstrate the importance of accurate LAT estimates for validation of remotely sensed estimates of C ab content in Norway spruce canopie

Response of green reflectance continuum removal index to the xanthophyll de-epoxidation cycle in Norway spruce needles

A dedicated field experiment was conducted to investigate the response of a green reflectance continuum removal-based optical index, called area under the curve normalized to maximal band depth between 511nm and 557nm (ANMB511-557), to light-induced transformations in xanthophyll cycle pigments of Norway spruce [Picea abies (L.) Karst] needles. The performance of ANMB511-557 was compared with the photochemical reflectance index (PRI) computed from the same leaf reflectance measurements. Needles of four crown whorls (fifth, eighth, 10th, and 15th counted from the top) were sampled from a 27-year-old spruce tree throughout a cloudy and a sunny day. Needle optical properties were measured together with the composition of the photosynthetic pigments to investigate their influence on both optical indices. Analyses of pigments showed that the needles of the examined whorls varied significantly in chlorophyll content and also in related pigment characteristics, such as the chlorophyll/carotenoid ratio. The investigation of the ANMB511-557 diurnal behaviour revealed that the index is able to follow the dynamic changes in the xanthophyll cycle independently of the actual content of foliar pigments. Nevertheless, ANMB511-557 lost the ability to predict the xanthophyll cycle behaviour during noon on the sunny day, when the needles were exposed to irradiance exceeding 1000 µmol m-2 s-1. Despite this, ANMB511-557 rendered a better performance for tracking xanthophyll cycle reactions than PRI. Although declining PRI values generally responded to excessive solar irradiance, they were not able to predict the actual de-epoxidation state in the needles examine

Mliječnost, sastav mlijeka, profil masnih kiselina i indeksi kvalitete mliječne masti kao utjecaj hranidbe ekstrudiranom punomasnom sojom

The aim of the study was to evaluate the effect of extruded full-fat soybean in diets of dairy cows on nutrient intake, milk yield, content and daily production of milk components, fatty acid (FA) profile and indices of milk fat quality. Four lactating Holstein cows were divided into control group fed a diet containing extruded rapeseed cake (R) and the experimental group fed a diet in which a part of extruded rapeseed cake was substituted by extruded full-fat soybean (RS). Dry matter intake (DMI), milk yield and milk composition were recorded. Milk FA profile was determined with subsequent calculation of atherogenicity index (AI), peroxidisability index (PI), desaturation indeks (DI) and spreadability index (SI) characterising quality of milk fat. Cows fed diet containing RS had higher DMI (17.8 kg/d) than cows fed diet containing R (16.8 kg/d, P0.05). PI was higher (P0,05). PI bio je veći (P<0,05) u RS nego u R, 5,54 i 5,06, respektivno

Degradable poly(ethylene oxide)-like plasma polymer films used for the controlled release of nisin

Poly(ethylene oxide) (PEO)-like thin films were successfully prepared by plasma-assisted vapor thermal deposition (PAVTD). PEO powders with a molar weight (Mw) between 1500 g/mol and 600,000 g/mol were used as bulk precursors. The effect of Mw on the structural and surface properties was analyzed for PEO films prepared at a lower plasma power. Fourier transform (FTIR-ATR) spectroscopy showed that the molecular structure was well preserved regardless of the Mw of the precursors. The stronger impact of the process conditions (the presence/absence of plasma) was proved. Molecular weight polydispersity, as well as wettability, increased in the samples prepared at 5 W. The influence of deposition plasma power (0-30 W) on solubility and permeation properties was evaluated for a bulk precursor of Mw 1500 g/mol. The rate of thickness loss after immersion in water was found to be tunable in this way, with the films prepared at the highest plasma power showing higher stability. The effect of plasma power deposition conditions was also shown during the permeability study. Prepared PEO films were used as a cover, and permeation layers for biologically active nisin molecule and a controlled release of this bacteriocin into water was achieved. © 2020 by the authors.Czech Science FoundationGrant Agency of the Czech Republic [GA17-10813S]; TBU in Zlin [IGA/CPS/2020/001

Ag Nanorod Arrays for SERS: Aspects of Spectral Reproducibility, Surface Contamination, and Spectral Sensitivity

Ag nanorod arrays prepared by oblique angle vapor deposition (OAD) represent regular, large area substrates for surface-enhanced Raman scattering (SERS) spectroscopy. We studied uniformity and spectral reproducibility of silver OAD-fabricated substrates (AgOADs) by spectral mapping of methylene blue. The results demonstrate good reproducibility apart from occasional “hot-spot” sites where the intensity is higher. The number of “hot-spots” represents 2%–6% of SERS-active sites of mapping substrate area. We were able to obtain good SERS spectra of testing amino acid tryptophan at 1 × 10−5 M concentration and three different free-base porphyrins down to ∼10−7 M concentration. We found out that keeping the AgOADs in a vacuum chamber overnight prevents the surface from binding any contaminants from the ambient atmosphere, without significant reduction in the SERS enhancement. Such substrates provide stable SERS enhancement even when stored for 1 year after preparation