|
|
Issues of stopping the hydration of alkali-activated slag using organic substances
Chadima, Jan ; Novotný, Radoslav (referee) ; Bílek, Vlastimil (advisor)
This thesis deals with the stopping of hydration of alkali activated slag by organic solvents and investigates to what extent the selected organic solvent affects the results of the analyses. The solvents used were acetone, diethyl ether, ethanol, isopropanol and methanol, and this is because these are the most commonly used organic solvents in practice. Thermogravimetric analysis along with differential thermal analysis was used to assess the degree of influence of organic solvents on the alkali activated slag and Portland cement samples. Methanol and acetone affected the samples the most and the longer the sample was stored in the solvent, the more it reacted with the organic solvent. The adverse interaction of organic solvent was greatest for the Portland cement samples. Samples that were rinsed with diethyl ether prior to analysis had lower mass losses than samples that were not rinsed. In the case of alkali activated slag, it was found that the way in which the thermogravimetric results were affected by organic solvents was highly dependent on the activator used, with the smallest effect observed for Na2CO3 activation, while the largest effect was observed for NaOH activation at temperatures below 600 °C, and for higher temperatures for water glass activation.
|
|
|
Issues of stopping the hydration of alkali-activated slag using organic substances
Chadima, Jan ; Novotný, Radoslav (referee) ; Bílek, Vlastimil (advisor)
This thesis deals with the stopping of hydration of alkali activated slag by organic solvents and investigates to what extent the selected organic solvent affects the results of the analyses. The solvents used were acetone, diethyl ether, ethanol, isopropanol and methanol, and this is because these are the most commonly used organic solvents in practice. Thermogravimetric analysis along with differential thermal analysis was used to assess the degree of influence of organic solvents on the alkali activated slag and Portland cement samples. Methanol and acetone affected the samples the most and the longer the sample was stored in the solvent, the more it reacted with the organic solvent. The adverse interaction of organic solvent was greatest for the Portland cement samples. Samples that were rinsed with diethyl ether prior to analysis had lower mass losses than samples that were not rinsed. In the case of alkali activated slag, it was found that the way in which the thermogravimetric results were affected by organic solvents was highly dependent on the activator used, with the smallest effect observed for Na2CO3 activation, while the largest effect was observed for NaOH activation at temperatures below 600 °C, and for higher temperatures for water glass activation.
|
|
|
Dealing with presentment in practice of choosen KHS Czech Republic and the issue of extraordinary events related to the methanol scandal.
LEŠTINOVÁ, Jana
In my master thesis, I have been mapping the work of regional hygiene stationswhile solving problems and providing services during exceptional situations in the methanol cause. For the practical part, I have decided to use the combination of the quantitative and the qualitative type of research. To gather the data, I have created a questionnaire that was composed of five open-ended questions. I have used an electronic way of distributing the questionnaire to all of the 14 regional hygiene stations of the Czech Republic. Unfortunately, there were only three hygiene stations that provided the needed data. The three participating hygiene stations were: KHS of South Bohemia region residing in ČeskéBudějovice, KHS of Vysočina region residing in Jihlava, and KHS of West Bohemia region residing in Plzeň. The secondary analysis of data was used to analyze and evaluate the given answers. For the needs of questionnaire examination, there has been created another questionnaire. It was composed of 14 closed questions that were mainly related to the knowledge and attitude of respondents to the given topic. All of the 206 respondents were residents of South Bohemia region. The questionnaire was posted on several internet web pages, and the research took place from March 2014 to July 2014. I have set several goals of the research. The first goal was to discover the number of incentives to be solved that were accepted by the three participating hygiene stations between the years 2008 and 2013. During the past six years, KHS of South Bohemia region, KHS ofVysočina region, and KHS of West Bohemia region experienced the growing trend in the number of incentives accepted. The lowest number of incentives accepted in KHS of South Bohemia region was in 2009, in KHS of Vysočina region in 2009 and 2010, and in KHS of West Bohemia in 2011. On the other hand, the highest number of incentives was experienced by all hygiene stations during the year 2013, and the number was significantly higher than in previous years. Another goal was to discover the number of alcohol accepted by KHS of South Bohemia during the methanol cause, the number of alcohol tested, and also the proportion of harmful alcohol that contained either methanol of isopropanol. In the South Bohemia region, there were 670 samples being tested during December 2012. Out of the 670 samples, there were 16 harmful samples, as 11 of them got over the technological limit of isopropanol contained, and 5 of methanol contained. Part of the master thesis was also to map the awareness of South Bohemia region residents of the methanol cause, and tolearn about their estimation on being able to recognize harmful alcohol by themselves without having it tested. The results have shown that 206 people which is equal to 100% of respondents were aware of methanol cause, and that they had at least basic information about it. 45 (22 %) respondents believed that they were able to recognize harmful alcohol by themselves, and 53 (26 %) respondents did not know about the possibility of having the alcohol tested by the hygiene stations. Out of all 153 well-informed respondents, only 3 (2 %) had their alcohol tested. The last goal of my master thesis was to discover the residents' opinion on hygiene stations. Concretely, I wanted to determine whether respondents would use a guide on how to report a complaint or an incentive. 100 % (206) of respondents have agreed on the fact that it would be useful if such a guide would be present on the web pages of each hygiene station. The research has also shown that 203 (99 %) respondents have answered that they assume that state administration bodies should be more helpful when giving information.Only 3 (1 %)respondents answered that the attitude of state administration is good enough.
|
guest ::
