Ultrasound-assisted electrochemical treatment of wastewaters containing organic pollutants by using novel Ti/Ta2O5-SnO2 electrodes

Advanced oxidation processes (AOPs) are modern methods using reactive hydroxyl radicals for the mineralization of organic pollutants into simple inorganic compounds, such as CO2 and H2O. Among AOPs electrochemical oxidation (EO) is a method suitable for coloured and turbid wastewaters. The degradation of pollutants occurs on electrocatalytic electrodes. The majority of electrodes contain in their structure either expensive materials (diamond and Pt-group metals) or are toxic for the environment compounds (Sb or Pb). One of the main disadvantages of electrochemical method is the polarization and contamination of electrodes due to the deposition of reaction products on their surface, which results in diminishing of the process efficiency. Ultrasound combined with the electrochemical degradation process eliminates electrode contamination because of the continuous mechanical cleaning effect produced by the formation and collapse of acoustic cavitation bubbles near to the electrode surface. Moreover, high frequency ultrasound generates hydroxyl radicals at water sonolysis. Ultrasound-assisted EO is a non-selective method for oxidation of different organic compounds with high degradation efficiencies. The aim of this research was to develop novel sustainable and cost-effective electrodes working as electrocatalysts and test their activity in electrocatalytic oxidation of organic compounds such as dyes and organic acids. Moreover, the goal of the research was to enhance the efficiency of electrocatalytic degradation processes by assisting it with ultrasound in order to eliminate the main drawbacks of a single electrochemical oxidation such as electrodes polarization and passivation. Novel Ti/Ta2O5-SnO2 electrodes were developed and found to be electrocatalytically active towards water (with 5% Ta content, 10 oxide film layers) and organic compounds oxidation (with 7.5% Ta content, 8 oxide film layers) and therefore these electrodes can be applicable in both environmental and energy fields. The synergetic effect of combined electrolysis and sonication was shown while conducting sonoelectrochemical (EO/US) degradation of methylene blue (MB) and formic acid (FA). Complete degradation of MB and FA was achieved after 45 and 120 min of EO/US process respectively in neutral media. Mineralization efficiency of FA over 95% was obtained after 2 h of degradation using high frequency ultrasound (381, 863, 1176 kHz) combined with 9.1 mA/cm2 current density. EO/US degradation of MB provided over 75% mineralization in 8 h. High degradation kinetic rates and mineralization efficiencies of model pollutants obtained in EO/US experiments provide the preconditions for further extrapolation of this treatment method to pilot scale studies with industrial wastewaters.

The analysis of knowledge retention mechanisms for leaving experts

The goal of this thesis is studying knowledge retention mechanisms used in cases of single experts’ leaving in the case company, analyzing the reason for the mechanisms choice and successfulness of knowledge retention process depending of that choice. The theoretical part discusses the origins of knowledge retention processes in the theoretical studies, the existing knowledge retention mechanisms and practical issues of their implementation. The empirical part of the study is designed as employees’ interview with later discussion of the findings. The empirical findings indicate the following reasons for knowledge retention mechanisms choice: type of knowledge retained, specialty of leaving experts and time and distance issues of a particular case. The following factors influenced the success of a retention process: choice of knowledge retention mechanisms, usage of combination of mechanisms and creation of knowledge retention plans. The results might be useful for those interested in factors influencing knowledge retention processes in cases of experts’ departure.

Attraction, recruitment and retention of high performing sales professionals case study: Lindström

The goal of this thesis is to gain more in-depth understanding of employer branding and offer suggestions on how this knowledge could be utilized in the case company. More in detail, the purpose of this research is to provide tools for improving Lindström’s organizational attractiveness and boosting the recruitment and retention of the segment of high-performing sales professionals. A strategy for reaching this particular segment has not been previously drawn and HR-managers believe strongly that it would be very beneficial for the company’s development and growth. The topic of this research is very current for Lindström, but also contributes on general level as companies are competing against each other in attracting, recruiting and retention of skilled workforce in the times of labor shortage. The research is conducted with qualitative methods and the data collection includes primary data through interviews as well as secondary data in the form of analysis on previous research, websites, recruitment material and discussions with Lindström’s HR department. This research provides a good basis for broader examination on the topic and presents development suggestions for the identified challenges. Based on the key findings Lindström’s HR department was advised to increase firm’s visibility, broaden recruitment channels, provide more hands-on knowledge about the sales positions and investigate their possibilities of developing sales reward systems.