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Measurement of conductivity of liquids
Mašláň, Stanislav ; Havránek, Zdeněk (referee) ; Beneš, Petr (advisor)
The first part of thesis is theoretical and it is the introduction into conductometry. It defines the essential terms of this field as well as contact and contactless methods of measurement of fluid conductivity and also the influential parasitic phenomena and possibilities of their elimination. The second part is dealing with design of the contactless transformer conductivity probe. The characteristics of designed probe are verified in the practical part of the thesis. The final part of the thesis is dealing with measurement according to the defined points in the assignment. The characteristics of several contact probes are verified and also the characteristic of the contactless transformer probe, which was implemented according to the design from the second part. Outcomes of these measurements establish the suitable power supply frequencies and currents for all these probes.
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Using konduktometric method for conductivity measurement of the corrosive layer of lead alloys
Neoral, Jiří ; Vaněk, Jiří (referee) ; Bača, Petr (advisor)
Lead-acid batteries are the oldest and most common type of secondary cells. Their biggest use is as a power source for a car starter. Bipolar lead-acid batteries could also be used for new applications such as power sources for hybrid electrical vehicles (HEV) for their high power. But there are still many technical problems limiting its use in these applications, which have to be overcome. This could cover parasite reactions as is gas creation, heat removal from the battery and another big problem is substrate corrosion. This diploma thesis concerns the actual state of bipolar lead batteries in the world with detail orientation to substrate corrosion. This thesis describes the conductometric method of lotion conductivity measurement and its modification for measurement of lead grid conductivity. From that we can find out, that when material loses more conductivity, the greater the corrosion. This thesis describes needed preparative experiments for assurance, that the conductometric method can be used for corrosion speed measurement and there are other experiments testing different lead alloys for corrosion speed.
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Dynamic light scattering and electroanalytical investigation of hyaluronan-amino acids systems
Muchová, Johana ; Kalina, Michal (referee) ; Chytil, Martin (advisor)
The bachelor thesis deals with interactions between low-molecular and high-molecular weight hyaluronic acid (HA) and protonized amphiphilic amino acids Lysine and Arginine. The interactions were observed in the area of low aminoacids concentrations with in the range 0–15 mmoldm-3. The interactions occur between the carboxyl groups of HA and the amino group of the protonated amino acids. Proving these interactions would allow us to physically modify HA and further more, use such a system as a carrier of pharmaceuticals. The resistence towards the ionic strength at the concentration of 0,015 and 0,15 moldm-3 NaCl was investigated. Previous results show that the system with unprotonated amino acids at low concetrations of electrolyte in the solution is rather disturbing. Therefore, the interactions were reinforced by the aminoacids protonation using HCl. The amino acids were protonated not only completely, but also partly because of negative influence of chloride anions. To study the interactions pH-metry, conductance and Dynamic Light Scattering were used.
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Characterization of hyaluronan interactions with albumin
Valentová, Kristýna ; Kratochvílová, Romana (referee) ; Chytil, Martin (advisor)
This bachelor thesis focuses on the research of physical interactions between hyaluronic acid and a protein albumin. In order to investigate these interactions following methods were used: pH and conductivity measurement, viscosimetry, turbidimetry and rheometry. The interactions were observed in solutions of fixed albumin concentration 1.0 gdm-3 and varying concentrations of hyaluronic acid from 0.1 to 2.0 gdm-3. Results were compared with a solution of hyaluronic acid without the addition of albumin. The results show that there are interactions between hyaluronic acid and albumin solutions, especially for those containing high molecular weight hyaluronic acid. The interactions exhibited a change in viscosity of solutions. We can see a reduction in viscosity after adding albumin to the reference solutions. The reduction is noticeable even in the low molecular weight HA solutions, but is not so significant.
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Study on interactions of protonated aminoacids with low-molecular weight hyaluronan
Chlumská, Jana ; Kalina, Michal (referee) ; Chytil, Martin (advisor)
This bachelor thesis deals with interactions between hyaluronic acid (HA) of low molecular weight (110-130 kDa) and protonated aminoacids lysine and 6-aminocaproic acid. For investigation of these interactions, methods such as pH-metry, conductance measurement, viscometry and dynamic light scattering were used. The electrostacic interactions between carboxylic group of HA and the aminogroup of the aminoacids are presumed. Proving these interactions would allow us to physically modify HA and further more, using such a system as a carrier of pharmaceuticals. The interactions of protonated lysine with HA were studied in pure water or in the solution of NaCl (c = 15 mmol•dm-3). Interactions of 6-aminocaproic acid were studied only in pure water. Both aminoacids were in the concentration range 0.9-20 mmol•dm-3. The decrease in the viscosity of the solutions indicates the interactions for lysine; for 6-aminocaproic acid the interactions also occured, but not as signifciantly as for the system containing lysine.
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Acidobasic behavior of carboxymethylcellulose solutions
Teslíková, Ivana ; Kislinger, Jiří (referee) ; Janeček, Jiří (advisor)
This work concerns with the study of acidobasic behavior of solutions of sodium salts of carboxymethylcellulose (CMC-Na). This behavior was investigated using acidimetric titrations of the salt solutions with potentiometric and conductometric indications. In order to determine the content of carboxylic groups in two different samples of CMC-Na (M1=90 kDa, DS1=0.7; M2=700 kDa, DS2=0.9), we employed the method of Ray von Wandruzska, originally proposed for the determination of the acidity of humic substances. The values of the degree of substitution (DS) obtained using this method correspond to the values declared by the producer. The small differences (of the order few percentage points) can be attributed to the humidity of the samples. The acidimetric titrations were performed also for solutions with different ionic strengths. There is an apparent effect of the ionic strength on the shape of titration curves; nevertheless these data were not used for any theoretical interpretation.
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