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Removal of Phenol, Hydroquinone and 2-Naphthol from Aqueous Solutions Using Tertiary Amine Modulated Cornstarch
No full textMaster of Science in Chemistry, 2022.Phenolics are a family of chemical compounds with at least one hydroxyl group attached directly to aromatic group. The sources of phenolics pollutants in water are mainly chemical industries and pharmaceutical. They are harmful and toxic even at modest concentrations. Some of their health effects are irreversible and it is prudent to remove phenolics from water to overcome them. The method that has attracted more attention is adsorption. Major strides have been made over years to search for highly selective and efficient bio-adsorbent for water remediation. Despite substantial achievements, there is need to search for bio-adsorbent which is ecofriendly and efficient. The objectives of the study were to modify cornstarch using triethanolamine and to characterize unmodified and modified cornstarch using Fourier Transform Infrared (FT-IR), to optimize selected adsorption parameters for the removal of phenol, hydroquinone and 2-naphthol in water using aminated cornstarch (ACS) and to determine the adsorption capacity of dried raw cornstarch (RCS) and ACS in removal of phenolic compounds (PCs). Pseudo first and second order kinetic models were used to determine mechanisms involved in both chemisorption and physisorption processes. The Langmuir and Freundlich isotherms were used to determine adsorption capacity of the ACS and whether it was monolayer or multilayer. The modulation of cornstarch was in two steps; chlorination of cornstarch using acetyl chloride reflux in aniline at 70 ℃ and 120 rpm for 5 hours, and amination using triethanolamine refluxed at 40 ℃ and 120 rpm for 3.5 hours. The FT-IR spectrum of the ACS showed strong broad band with increased intensity at 3295.44cm-1 which confirmed C-N stretch of amine group and N-H stretch of amine salt were anchored. The efficiency of modified cornstarch in phenolics removal at different pH levels, contact time, initial phenolics concentration and dosage of ACS in aqueous media at constant temperature (25±1 ℃) were investigated. Batch studies revealed that maximum removal of PCs was realized at a contact time of 10 mins, pH of 5.0-6.0 and constant temperature of 25±1 ℃ for the phenol, hydroquinone and 2-naphthol compounds. The uptake increased with increase in the dosage of ACS and initial concentration of phenolics. The rate of adsorption process was best described by the pseudo – second order kinetic model, indicating that the rate mechanism was chemisorption. The maximum uptake of PCs occurred at initial concentration of 10ppm and then plateaued. The batch experimental data obtained best fitted into the Langmuir isotherm with regression coefficient, R2=0.9998, 0.9999, 1.000 and monolayer adsorption capacities of 4.297, 4.585 and 5.048 mg/g for phenol, hydroquinone and 2-naphthol respectively. The adsorption process was monolayer and homogenous in nature. These adsorption capacities were relatively higher than many reported processes, thus indicating that the ACS an effective adsorbent for removal of PCs from aqueous media. The findings from this study provides an alternative biopolymer that may be used for the removal of phenolic compounds from water.Murang'a University of Technolog
Natural Ecosystem
No full textRelating to human resource function, compensation (often referred to as pay, wage, salary) is the monetary and non-monetary reward offered to an employee in exchange of their contribution to labour. The contributions can be their time, knowledge, skills, abilities and commitment to an organization or certain temporal work. Whereas people traditionally work to get paid, people are increasingly considering non-monetary benefits that ensure stability in the long run e.g. having health care plan, long-term disability protection, and retirement plans (See figure 1). This has led human resource managers to come up with attractive compensation packages for different employees they recruit. Human resource total compensation remains the largest expense for many organizations hence having a good compensation plan helps to strike a balance between employee satisfaction and maintaining overall human resource strategy of minimizing costs
Complexity Metrics for Statechart Diagrams
No full textModel-Driven Development and the Model-Driven Architecture paradigm have in the recent past been emphasizing on the importance of good models. In the Object-Oriented paradigm one of the key artefacts are the Statechart diagrams. Statechart diagrams have inherent complexity which keeps increasing every time the diagrams are modified, and this complexity poses problems when it comes to comprehending the diagrams. Statechart diagrams provide a foundation for analysing the dynamic behaviour of systems, and therefore, their quality should be maintained. The aim of this study is to develop and validate metrics for measuring the complexity of UML Statechart diagrams. This study used design science which involved the definition of metrics, development of a metrics tool, and theoretical and empirical validation of the metrics. For the measurement of the cognitive complexity of statechart diagrams, this study proposes three metrics. The defined metrics were further used to calculate the complexity of two sample statechart diagrams and found relevant. Also, theoretical validation of the defined metrics was done using the Weyuker’s nine properties and revealed they are mathematically sound. Empirical validations were performed on the metrics and results indicate that all the three metrics are good for the measurement of the cognitive complexity of statecharts
Assessment of Climate Change Impact and Vulnerability of Immovable Cultural Heritage Sites: A Case Study of Kenya’s Coastline
No full textMaster of Science in Hospitality and Tourism Management, 2022.Researchers have developed interest on climate change as a contemporary affecting the tourism sector. Although climate change is widely acknowledged as a global phenomenon, the actual and projected effects are still being debated in the scientific and political forums. Locally, there is evidence of uncertain trends regarding the manifestation of global climate change and the required adjustments. Climate change is negatively affecting the tourism sector which is the backbone of economic development. Cultural heritage is important in that it provides tourism opportunities, enhances economic growth, stimulates learning and fosters cultural identity. Yet, change in climate elements of temperature, rainfall and rising sea level impacts the preservation of values embodied in the immovable cultural resources. Cultural heritage has survived the past centuries but the previous adaptation may not sustain them in the extreme climate conditions in the future. Some of the cultural heritage sites like Vasco da Gama, Fort Jesus and Jumba la Mtwana have been highlighted to have physical damage. The study was guided by the following objectives; general objective: assessing the effects of climate change and vulnerability of immovable cultural heritages and the responses strategies employed by the destination stakeholders. Specific objectives which include to: analyze the impacts of climate change on the immovable cultural heritage sites; assess the vulnerability of immovable cultural heritage sites to climate change; identify the adaptation strategies of the immovable cultural heritage sites; determine response to barriers in adapting immovable cultural heritage to climate change; identify how the stakeholder’s, maximize opportunities that arise in adapting immovable cultural heritage to climate change. The study was guided by the theory of adaptation. The study covered eight immovable cultural heritage sites identified in Kilifi and Mombasa counties. Questionnaires, interviews and observation methods was used in data collection. The study used descriptive analysis in analyzing descriptive data and narrative analysis for qualitative data. The results of the findings indicated that apart from climate change impacts being a major threat to the immovable cultural heritages along Kenyan coastline, old age and human activities are also other factors facilitating the deterioration of the cultural heritages. Results of the study will provide information on existing knowledge gaps concerning the effects of climate change on the immovable cultural heritage thus increase baseline data and provide solutions to heritage sites facing the effects of climate change. The study further recommended the need for more and continuous research on the causes of cultural heritage sites deterioration and measurement of how the climate change elements affects the immovable cultural heritage sites.Murang'a University of Technolog
Development of DSTATCOM Optimal Sizing and Location Technique Based on IA-GA for Power Loss Reduction and Voltage Profile Enhancement in an RDN
No full textThe efficiency of electrical distribution systems is being more affected by the increase in voltage drops and power losses. These issues of voltage drop and power loss can be significantly minimized by the incorporation of a Distribution Static Compensator (DSTATCOM) in the distribution network. However, inappropriate positioning and sizing of DSTATCOM can undermine its efficiency. Despite the contributions of many researchers to the optimal placement of DSTATCOM and other compensators in distribution networks, the problems of voltage drop, power losses, and power quality persist, necessitating the need for additional research in this area. In this paper, an innovative technique based on hybridized Immune and Genetic Algorithm (IA-GA) for optimal DSTATCOM placement and sizing for three distinct load levels is proposed. Simulation and analysis of the proposed algorithm were carried out using IEEE-33 bus radial distribution network (RDN) in MATLAB. The simulation results demonstrate a substantial decrease in power loss and a significant improvement in the voltage profile. Evaluation of the proposed method against existing techniques reveals that the proposed technique outperforms IA and PSO in terms of decreasing power loss and enhancement of voltage profiles. A cost-benefit analysis was performed, and it was discovered that the proposed technique yields improved annual cost savings
Rutile Concentration by Reduction of Titanium Ore - Laterite Mixture Using Biomass
No full textRutile is a mineral which is used in making paints, ointments, tooth paste, sunscreens, just to mention a few products. Titanium metal makes alloys with less density and resistance to corrosion, which are used in making aircraft and marine vessels. Rutile is obtained from ores by concentration method using chemicals, a process which is very expensive. In this paper, we have investigated on alternative method of concentrating rutile from titanium ores. This was done by reduction of the mixture of titanium ore and laterite using biomass. The titanium ores were obtained from Maragwa location in Tharaka Nithi County and mineralogical and chemical composition carried using XRD and AAS. The mixture of 25 g of the ore, 2 g of laterite and 1.0 g of ground dry biomass was put into clay pots. The samples were placed in a charcoal burner and heated at temperature range 800 - 900°C for two hours and the temperature monitored using a thermocouple. After two hours the sample mixtures were cooled to room temperature and serial magnetic separation done. The samples were digested and analyzed for rutile using AAS and XRD. The results show that rutile composition increased from about 0.40% in raw ore to about 2.62%, which represents 2.22% increase. This percentage increase varies depending on the ore mineralogy and chemical composition. Therefore, titanium ores with low concentration of iron can be concentrated using laterite rich in iron. Besides obtaining rutile, the method offers a successful way of cleaning the environment by using biomass from municipal waste