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Evaluation of the Effectiveness of Treatments to Remove Per- and Polyfluoroalkyl Substances from Water—Are We Using the Right Approach? Proposal of a Paradigm Shift from “Chemical Only” towards an Integrated Bio-Chemical Assessment
(MDPI, 2023-09-28) Carnevale Miino, Marco; Halešová, Taťána; Macsek, Tomáš; Raček, Jakub; Hlavínek, Petr
Per- and polyfluoroalkyl substances (PFASs) have been under intense investigation by the scientific community due to their persistence in the environment and potentially hazardous effects on living organisms. In order to tackle the presence of these compounds in water, to date, the research has been strongly focused on the evaluation of the effectiveness of different types of technologies. Considering the extreme complexity of the matter of PFASs and our relatively low knowledge in this topic, the following question arises: is the “chemical only” approach that is followed for evaluating the effectiveness of technologies for PFAS removal from water reliable enough? In this work, some limitations of the present approach are discussed, highlighting the reasons why it cannot be considered a reliable tool to correctly estimate the effectiveness of technology when referring to emerging compounds such as PFASs. Bioassays can play a key role in moving towards an integrated bio-chemical evaluation (chemical analysis and ecotoxicological evaluation), which is strongly encouraged. This represents the only way to completely characterize a water matrix and fully evaluate the impact of technologies when dealing with micropollutants in water, such as PFASs. Future research should focus on defining an optimal battery of bioassays that specifically fit to best represent changes in water quality in terms of short- and long-term impacts on living organisms.
Alternative technology of constructing masonry structures designed for areas with increased seismic activity
(Elsevier, 2016-07-21) Sedlmajer, Martin; Zach, Jiří; Novák, Vítězslav; Peterková, Jitka; Horský, Antonín
The Czech Republic is a country which generally sees low seismic activity; however, this activity needs to be taken into account in ca 50 % of the country’s area with 10 districts being considered as having seismic activity higher than 0.08 g. In terms of masonry structures, this issue concerns mainly the execution of the head joints of the masonry and its reinforcement (both in the direction of the bed joint and in the perpendicular direction). All these technologies are rather difficult and expensive to implement. The research focuses on assessing the possibilities of constructing dry masonry and binding it with polyurethane foam. This method allows for significantly higher shear strength of the masonry and appears to be an interesting alternative in the area of constructing buildings in seismically active areas. The structure was stiffened by filling hollow masonry units with large cavities with polyurethane foam. The PUR foam was sprayed into the units during construction. The foam thus applied hardens perpendicularly to the bed joint of the masonry and, having expanded throughout the clay units, it functions as a binder and a stiffening component to the masonry as a whole. The initial shear and flexural strength of the masonry segments was determined. The newly developed method of filling the cavities of masonry units with PUR foam was compared with the conventional method of constructing masonry by means of bonding the blocks with mortar or PUR foam in the bed joints (with no cavities filled). The filling of the masonry unit cavities brought a significant increase in the shear and flexural strength of the masonry. This indicates the stiffness of the structure increased as well.
Evaluation of Investment Risks in CBA with Monte Carlo Method
(Mendel University in Brno, 2015-03-30) Korytárová, Jana; Janovská, Barbora
Investment decisions are at the core of any development strategy. Economic growth and welfare depend on productive capital, infrastructure, human capital, knowledge, total factor productivity and the quality of institutions. Decision-making process on the selection of suitable projects in the public sector is in some aspects more difficult than in the private sector. Evaluating projects on the basis of their financial profitability, where the basic parameter is the value of the potential profit, can be misleading in these cases. One of the basic objectives of the allocation of public resources is respecting of the 3E principle (Economy, Effectiveness, Efficiency) in their whole life cycle. The life cycle of the investment projects consists of four main phases. The first pre-investment phase is very important for decision-making process whether to accept or reject a public project for its realization. A well-designed feasibility study as well as cost-benefit analysis (CBA) in this phase are important assumptions for future success of the project. A future financial and economical CF which represent the fundamental basis for calculation of economic effectiveness indicators are formed and modelled in these documents. This paper deals with the possibility to calculate the financial and economic efficiency of the public investment projects more accurately by simulation methods used.
Numerical Simulation of the Effect of Heat Gains in the Heating Season
(Elsevier, 2012-03-08) Šikula, Ondřej; Plášek, Josef; Hirš, Jiří
This paper is concerned with the description and verification of an energy model of a building using the BSim software. The aim is to determine the effect of the basic heat gains on the energy consumption of a building. Simulations were performed on the basis of the actual hourly-interval climatic data over a whole year. It has been found, that the highest heat gain comes from solar radiation.
Technology of concrete with low generation of hydration heat
(Elsevier, 2013-10-23) Zach, Jiří; Sedlmajer, Martin; Peterková, Jitka; Nevařil, Aleš
Modern technology of concrete includes a comprehensive elaboration of proposal related to concrete composition depending on the required parameters of fresh and hardened concrete. One of the fields related to the technologies of concrete is the issue of the generation of hydration heat. Heat generation in the process of hydration is observed mainly in concretes. Here, we emphasize the need of avoiding potential cracking due to thermal expansion, which is mainly the case of putting concrete in massive units and also other cases in which critical stress and damaging to the concrete may occur due to the influence of high temperature gradients. Hydration of concrete is a very difficult and complex process that depends on a number of direct and indirect factors. Speed indicators of hydration reactions are represented by the intensity of the hydration heat generation. The paper deals with the general methodology for the proposal of prescriptions for concrete mass intended for structures with high demands on low level of hydration heat generation. There are various intermediate steps presented, those leading to a successful proposal of concrete composition, including verification of the proposed measures and creation of a 3D model of calculation.

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