263 research outputs found

    E-Shop and CMS with universal data model

    Get PDF
    Náplní této bakalářské práce je analýza a návrh e-shopu a systému pro správu obsahu využívajícího univerzální datový model relačních databází.  Část práce se zabývá problematikou obecného univerzálního datového modelu.  Následující části se zabývají návrhem konkrétního univerzálního datového modelu a také návrhem ostatních částí systému. V práci byla ověřena použitelnost takového modelu pro e-shop i systém pro správu obsahu a také ověřen zájem zákazníků o tento typ systému.The content of this bachelor's thesis is analysis and design of e-shop and content management system which is using universal data model of relational databases. Part of the thesis is focused on problematics of general universal data model. The following sections are focused on design of specific universal data model and design of other parts of the system. The work verified the applicability of such a model for e-shop and content management system and also verified customers interest in this type of system.

    Identification of surface active components in glass forming melts by thermodynamic model

    Get PDF
    Nine compositional series of 15(Na2O, K2O)center dot 10(CaO, ZnO)center dot 75(ZrO2, SiO2) glass-forming melts were studied, all with the ZrO2 content of 0, 1, 3, 5 and 7 mol.%. The investigated glass compositions were obtained by equimolar substitutions ZrO2 / SiO2, ZnO / CaO and K2O / Na2O. Surface tension of studied glassforming melts was de-termined by the sessile and pendant drop profile numerical analysis in the temperature range (1250 1500) degrees C. The experimental values of melt density were used. The linear temperature dependence of surface tension was observed for all samples with only small differences between values obtained from sessile and pendant drop profiles. The Shakhmatkin and Vedishcheva thermodynamic model (TDM) was evaluated for each glass melt at temperature of 1400 degrees C. The total number of 36 components was considered in TDM. Only 26 components were present with non-negligible equilibrium amount. The surface tension was described by the multilinear function of equilibrium amounts of statistically independent non-negligible components of the TDM. The surface active components were identified by negative values of their coefficients. Such way the N3S8 and C2ZrS4 were identified as "strongly" surface active and NCS5 and KS4 as probably surface active. Regarding the oxide compositional point of view, the surface tension was mostly influenced by ZnO (increase with the addition of the oxide) and by K2O (decrease with the addition of the oxide)

    Assessment of the Bioavailability of Cu, Pb, and Zn through Petunia axillaris

    Get PDF
    Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soils. For this reason, determining the chemical form of a metal in soils is important to evaluate its mobility and the potential accumulation. The aim of this examination is to evaluate the accumulation potential of Petunia x hybrida as a flower crop for three metals, namely, copper (Cu), lead (Pb), and nickel (Ni). Trace metals (Zn, Cu, and Pb) in the soils were partitioned by a sequential extraction procedure into H2O extractable (F1), 1 M CH3COONa extractable (F2). Chemical fractionation showed that F1 and F2 fraction of the metals were near 1% and residue was the dominant form for Zn, Cu, and Pb in all samples. Using fluorescence method allowed us to estimate condition of the plants by adding metals. As result of plant and soil analysis, we can conclude that Petunia has Cu, Zn, and Ni tolerance and accumulation. Therefore, Petunia has the potential to serve as a model species for developing herbaceous, ornamental plants for phytoremediation

    Reduced real lifetime of PV panels – Economic consequences

    Get PDF
    The maintenance and analyzing failures of PV systems and plants are becoming more and more important issues. Our data from the long-term operation of 85 photovoltaic power plants in central Europe show that their actual lifetime is about half that of the originally planned lifetime. After about 10 years, serious failures of 1st tier (bankable) PV panels occur at an increasing rate. This article presents selected typical data and describes the most serious failures. Furthermore, economic calculations of returns on investment are carried out in relation to the price of electricity, which is currently changing at a rapid pace. It shows that the PV panel lifetime reduction from 20 to 30 years, declared at commercial leaflets, to real lifetime about 10–12 years can reduce PV power plant profit substantially, but the investment is still worth it. The reason is that after 10–12 years ser vice/maintenance expenses to replace damaged PV panels and inverters are growing very quickly. The new information could be helpful for owners of PV power plants to get a more realistic estimation of profits

    Towards Integrated Ethical and Scientific Analysis of Geoengineering: A Research Agenda

    Get PDF
    Concerns about the risks of unmitigated greenhouse gas emissions are growing. At the same time, confidence that international policy agreements will succeed in considerably lowering anthropogenic greenhouse gas emissions is declining. Perhaps as a result, various geoengineering solutions are gaining attention and credibility as a way to manage climate change. Serious consideration is currently being given to proposals to cool the planet through solar-radiation management. Here we analyze how the unique and nontrivial risks of geoengineering strategies pose fundamental questions at the interface between science and ethics. To illustrate the importance of integrated ethical and scientific analysis, we define key open questions and outline a coupled scientific-ethical research agenda to analyze solar-radiation management geoengineering proposals. We identify nine key fields of coupled research including whether solar-radiation management can be tested, how quickly learning could occur, normative decisions embedded in how different climate trajectories are valued, and justice issues regarding distribution of the harms and benefits of geoengineering. To ensure that ethical analyses are coupled with scientific analyses of this form of geoengineering, we advocate that funding agencies recognize the essential nature of this coupled research by establishing an Ethical, Legal, and Social Implications program for solar-radiation management

    Fast Benchtop Fabrication of Laminar Flow Chambers for Advanced Microscopy Techniques

    Get PDF
    Background: Fluid handling technology is acquiring an ever more prominent place in laboratory science whether it is in simple buffer exchange systems, perfusion chambers, or advanced microfluidic devices. Many of these applications remain the providence of laboratories at large institutions with a great deal of expertise and specialized equipment. Even with the expansion of these techniques, limitations remain that frequently prevent the coupling of controlled fluid flow with other technologies, such as coupling microfluidics and high-resolution position and force measurements by optical trapping microscopy. Method: Here we present a method for fabrication of multiple-input laminar flow devices that are optically clear [glass] on each face, chemically inert, reusable, inexpensive, and can be fabricated on the benchtop in approximately one hour. Further these devices are designed to allow flow regulation by a simple gravity method thus requiring no specialized equipment to drive flow. Here we use these devices to perform total internal reflection fluorescence microscopy measurements as well as position sensitive optical trapping experiments. Significance: Flow chamber technology needs to be more accessible to the general scientific community. The method presented here is versatile and robust. These devices use standard slides and coverslips making them compatible with nearly all types and models of light microscopes. These devices meet the needs of groups doing advanced optical trapping experiments, but could also be adapted by nearly any lab that has a function for solution flow coupled with microscopy

    Protection gaps and restoration opportunities for primary forests in Europe

    Get PDF
    Aims: Primary forests are critical for forest biodiversity and provide key ecosystem services. In Europe, these forests are particularly scarce and it is unclear whether they are sufficiently protected. Here we aim to: (a) understand whether extant primary forests are representative of the range of naturally occurring forest types, (b) identify forest types which host enough primary forest under strict protection to meet conservation targets and (c) highlight areas where restoration is needed and feasible. Location: Europe. Methods: We combined a unique geodatabase of primary forests with maps of forest cover, potential natural vegetation, biogeographic regions and protected areas to quantify the proportion of extant primary forest across Europe\u27s forest types and to identify gaps in protection. Using spatial predictions of primary forest locations to account for underreporting of primary forests, we then highlighted areas where restoration could complement protection. Results: We found a substantial bias in primary forest distribution across forest types. Of the 54 forest types we assessed, six had no primary forest at all, and in two-thirds of forest types, less than 1% of forest was primary. Even if generally protected, only ten forest types had more than half of their primary forests strictly protected. Protecting all documented primary forests requires expanding the protected area networks by 1,132 km2 (19,194 km2 when including also predicted primary forests). Encouragingly, large areas of non-primary forest existed inside protected areas for most types, thus presenting restoration opportunities. Main conclusion: Europe\u27s primary forests are in a perilous state, as also acknowledged by EU\u27s “Biodiversity Strategy for 2030.” Yet, there are considerable opportunities for ensuring better protection and restoring primary forest structure, composition and functioning, at least partially. We advocate integrated policy reforms that explicitly account for the irreplaceable nature of primary forests and ramp up protection and restoration efforts alike
    corecore