Photocatalytic hydrogen generation from water-methanol solution in the presence of vermiculites

Diplomová práce se zabývá fotokatalytickou generací vodíku z roztoku voda-metanol v přítomnosti vermikulitů. Produkce vodíku, jakožto jednoho z hlavních kandidátů budoucích energetických paliv, byla zajištěna fotokatalytickými procesy štěpení vody, které byly pro vyšší účinnost posíleny přítomností obětního činidla, jímž byl metanol. Vermikulit tepelně zpracovaný při 500 a 700 °C byl použit jako substrát pro vysrážení nanočástic hematitu (α-Fe2O3) v kompozitech α Fe2O3/vermikulit, které byly použity jako fotokatalyzátor. Připravené fotokatalyzátory byly charakterizovány rentgenovou fluorescenční spektroskopií, rentgenovou difrakční analýzou a fyzisorpcí dusíkem. Fotokatalytická generace vodíku probíhala ve vsádkovém fotoreaktoru v přítomnosti připravených nanokompozitů po dobu 4 hodin. Jako zdroj záření byla použita UV lampa s vlnovou délkou 254 nm. Fotokatalytická aktivita vzorků byla korelována s jejich fyzikálně-chemickými vlastnostmi. Nejvyšších výtěžků vodíku bylo dosaženo v přítomnosti fotokatalyzátoru Fe/V–700, který měl největší specifický povrch a největší velikost krystalitů.The thesis deals with photocatalytic hydrogen generation from water-methanol solution in the presence of vermiculites. Hydrogen production, as one of the main candidates for future energy fuels, was ensured by photocatalytic water splitting processes, which were enhanced for higher efficiency by the presence of a sacrificial agent, which was methanol. Vermiculite heat treated at 500 and 700 °C was used as a substrate for the precipitation of hematite (α-Fe2O3) nanoparticles in α Fe2O3/vermiculite composites, which were used as photocatalyst. The prepared photocatalysts were characterized by X-ray fluorescence spectroscopy, X-ray diffraction analysis and nitrogen physisorption. The photocatalytic hydrogen generation was carried out in a seeded photoreactor in the presence of the prepared nanocomposites for 4 hours. A UV lamp with a wavelength of 254 nm was used as the radiation source. The photocatalytic activity of the samples was correlated with their physicochemical properties. The highest hydrogen yields were achieved in the presence of the Fe/V–700 photocatalyst, which had the largest specific surface area and the largest crystallite size.617 - Katedra chemievýborn

The State of the Soil Organic Matter and Nutrients in the Long-Term Field Experiments with Application of Organic and Mineral Fertilizers in Different Soil-Climate Conditions in the View of Expecting Climate Change

Soil organic matter (SOM) plays an important role in the terrestrial ecosystems and agroecosystems. Changes in the agricultural sector in the countries of the Central and Eastern Europe (the Czech Republic, Slovakia, Poland, etc.) within the past 25 years have negatively affected the SOM and contributed to the soil degradation. The aim of this chapter is the evaluation of the long-term application of mineral fertilizers and farmyard manure: the Control (without fertilization), farmyard manure (FYM + 0), FYM accompanied with NPK (FYM + N3PK), and FYM with mineral nitrogen FYM + N (FYM + N2), on the essential chemical properties of the soil and yield of the fundamental arable crops in the long-term field experiments, established in different soil and climate conditions (black soils, brown soils, cambisols, altitude ranging from 260 to 650 m a.s.l.) of the Czech Republic in 1955, using the modern multi-criteria statistical methods (PCA, FA, CLU, etc.). The long-term and regular application of organic manure and organic manure with mineral fertilizers (FYM + N3PK and FYM + N2) optimize the soil characteristics, stabilize crop and feedstuff production, and increase the adaptation potential of the soil in the Czech Republic, which is supposed to be weakened due to the expected changes of the environmental conditions in the near future

Cell-based and multi-omics profiling reveals dynamic metabolic repurposing of mitochondria to drive developmental progression of Trypanosoma brucei

Mitochondrial metabolic remodeling is a hallmark of the Trypanosoma brucei digenetic life cycle because the insect stage utilizes a cost-effective oxidative phosphorylation (OxPhos) to generate ATP, while bloodstream cells switch to aerobic glycolysis. Due to difficulties in acquiring enough parasites from the tsetse fly vector, the dynamics of the parasite’s metabolic rewiring in the vector have remained obscure. Here, we took advantage of in vitro–induced differentiation to follow changes at the RNA, protein, and metabolite levels. This multi-omics and cell-based profiling showed an immediate redirection of electron flow from the cytochrome-mediated pathway to an alternative oxidase (AOX), an increase in proline consumption, elevated activity of complex II, and certain tricarboxylic acid (TCA) cycle enzymes, which led to mitochondrial membrane hyperpolarization and increased reactive oxygen species (ROS) levels. Interestingly, these ROS molecules appear to act as signaling molecules driving developmental progression because ectopic expression of catalase, a ROS scavenger, halted the in vitro–induced differentiation. Our results provide insights into the mechanisms of the parasite’s mitochondrial rewiring and reinforce the emerging concept that mitochondria act as signaling organelles through release of ROS to drive cellular differentiation

How to use a language of art in religious pedagogig

The thesis deals with the signification of art for holistic development of an individual. It also deals with symbol as one of the most important means of expression in art, with symbol in the Bible, in image art and its role in the process of individualization. It includes the characteristic of adolescent age with regard to ability of understanding the symbols. It deals with the theory of the didactic of symbols, the explanation of the meaning of 'second naivety' and the concept of a teaching unit as a practical sample for working with symbols interpreting picture

The methodics of plant nutrition and fertilization by phosphorus

The methodics inform about situation in plant nutrition and fertilization by phosphorus on arable soil in Czech Republic. The methodics indicate two approaches for assessment of fertilization demand utilized as well for checking of phosphorus input limits requested by different legislation. There is evaluated need of phosphorus for expected production and soil fertility stabilization

The methodics of plant nutrition and fertilization by potassium

The methodics inform about situation in plant nutrition and fertilization by potassium on arable soil in Czech Republic. Methodics is found on utilize analytical procedure for determination of content available potassium (Mehlich 3), whose it is possible subsequently use for calculation optimal fertilization

The Content of Topsoil Nutrients, Ph and Organic Carbon as Affected by Long-Term Application of Mineral and Organic Fertilisers

Soil is the fundamental element in agriculture and is affected in a variety of ways. Besides other things, the long-term application of mineral and organic fertilisers can significantly influence the topsoil pool of nutrients, organic carbon content and pH. Within the scope of longterm field experiments in Praha-Ruzyně, we evaluated the effect of six fertiliser treatments - unfertilised Control, farmyard manure (FYM), cattle slurry (CAT), cattle slurry amended with straw from previous cereals (CAT+STR), mineral fertiliser (NPK) and NPK amended with FYM (NPK+FYM) on a topsoil pool of nutrient content, organic carbon content (Cox) and pH between the years 2001 and 2012. In the selected period, the fertiliser treatment did not influence the N and Cox content (ranging from 0.126% to 0.143%). Phosphorus and potassium were significantly higher in the NPK+FYM treatment (109.82 and 279.27 mg/kg, respectively), while calcium and magnesium were significantly lower in the NPK treatment (2,973 and 134.95 mg/kg, respectively). Application of mineral fertilisers significantly decreased the value of pH, influencing the Ca and Mg topsoil concentrations. Organic fertilisers cannot provide a sustainable amount of nutrients to generate high yields in a short time, but release their nutrients slowly and the range of nutrients is wider. Mineral fertilisers, if not amended with organic fertilisers, can provide huge doses of nutrients, which can be quickly reused for high yields, but negatively influence the pH value, resulting in a decrease in the pool of Ca and Mg

Effect of Digestate on Soil Organic Carbon and Plant-Available Nutrient Content Compared to Cattle Slurry and Mineral Fertilization

Digestate contains many valuable nutrients, including nitrogen (N), phosphorus (P), and potassium (K); however, it is characterized by relatively little organic matter. The objective of this study was to assess the four-year impact of digestate (Dig) application, digestate + straw (Dig + St), cattle slurry (Csl), and mineral fertilization (NPK) on soil organic carbon (SOC), total nitrogen (TN), mineral N (Nmin), and the content of plant-available P and K. Fertilization did not have any significant influence on SOC, TN, and SOC/TN parameters. Yet, in comparison with control, there was an upward trend in the concentration of SOC and TN in the topsoil, where fertilizers were applied. In contrast to SOC and TN, fertilizer treatment significantly affected the content of P, K, and Nmin, and the differences depended on the soil depth and the fertilizer used. On average, the highest content of P was obtained in Csl treatment, but the highest content of K was observed in Dig + St. The effect of treatment on Nmin in spring was as follows: NPK = control < Csl = Dig + St < Dig. Straw plowing increased the bio-immobilization of N with digestate and, at the same time, lowered the content level of nitrates in soil