Post combustion CO2 capture using aqueous amine solvents: Investigations on molecular structure-activity relationships for amine solvents

The study in this dissertation focuses on chemical absorption of CO2 using aqueous amine which is expected to be the technology of choice for early large scale deployment of postcombustion carbon capture (PCC). However the technology still faces challenges. Reduction in cost of this process, in terms of both capital and operational is required to make the process economically feasible. One possible approach for it, is the improvement of absorbents. Since this process is chemically driven, understanding fundamental chemistry of amine-CO2 reactivity could assist the rational development of the absorbents. With respect to primary and secondary amines, the amine carbamate formation reaction and the carbamate hydrolyses reaction are important reactions. The equilibrium constants governing these reactions can define the performance of amine solvents. Understanding the molecular structure-activity relationships for the CO2-aqueous amine reactions aid prediction/estimation of their equilibrium constants. The influence of molecular structure on the free energy of activation of a reaction or the reaction may be treated as the sum of independent contributions of polar, resonance and steric effects of substituents in the molecule. We can separate theses effects individually and assign numerical values to elements or substituent groups as empirical constants related to their effects on reaction rates and equilibria. The “Taft polar parameter” defines a quantitative scale which assigns a value to the polar nature of a substituent. The study reported in this thesis aims to increase understanding of aqueous amine-CO2 reactivity and estimate the equilibrium constants of carbamate formation and carbamate hydrolysis reactions by means of Taft polar parameter. According to the relations between Taft polar parameter and the equilibrium constants, relative reduced electron density on N atom leads to increased alkylamine carbamate formation and decreased alkylamine carbamate hydrolysis. Note that this study is limited to primary (1o) alkylamines. The relative electron density, present on the N nucleus, which is depending on molecular structure and medium effects influences the chemical reactions between amine and CO2. Therefore, 15N NMR experiment data was also used to qualitatively analyse the structure-activity relationships of 1o alkylamines. The current study provides evidence that in addition to polar effects from substituents, water solvents and steric hindrance (in terms of electron delocalization) influence the reaction of the alkylamine toward CO2. The results show that higher basicity and higher α -C substituent effect (steric hindrance) reduce carbamate formation. Further, this dissertation includes modifying analytical methods for speciation in carbonated aqueous amine solutions which is required to determine the equilibrium constants of interested reactions. In this respect, a complementary wet chemical method (WCM) for determination of species distribution in carbonated aqueous amine solution was developed. The method employs analytical techniques readily available in any laboratory. The results obtained using WCM were compared to those obtained using 13C NMR analysis for identical solutions for validation. They were in good agreement. The method was then used for speciation in carbonated primary alkylamine solutions; propyl-, butyl- and pentylamine. Application of Raman spectroscopy as an analytical tool to determine the speciation of carbonated aqueous alkanolamine systems was attempted. It constitutes a simple ‘short-cut’ type approach to semi-quantitative speciation information employing measurement of selected Raman bands in conjunction with an internal standard (ClO4 −), assisted by 13C-NMR .Published versio

Teaching Kindergarten Students about the Water Cycle through Arts and Invention

Research evidence for the benefits of arts integration is mounting. The purpose of this study was to determine if integration of the arts was an effective strategy for teaching the water cycle to kindergarten students. The study included lessons that supported both a science and an engineering standard of the Next Generation Science Standards and national arts standards. The phenomenological study examined the lived experiences of children as they learned and demonstrated understanding through drawings, watercolor paintings, dramatization of a water cycle poem, and the invention and testing of a waterproof boot. Participants were 12 kindergarten students (7 male, 5 female) aged 5-6 years, attending a public elementary school in the Midwestern United States. The three major themes that emerged from the phenomenological study were: 1) aspects of typical lessons, 2) art-enhanced learning, and 3) art-enhanced teacher understanding of student ideas. Findings revealed arts integration was motivating, engaging for the students, and an effective strategy for teaching about the water cycle. The art-based activities provided deeper insights about student understanding and misconceptions than traditional forms of assessment

Factors Affecting Private Sector Bankers’ Job Satisfaction in Sri Lanka: A Case Study

Job satisfaction is a positive and a delighted feeling of the employees’ job or work roles that they are currently dealing with. This emotion has an inspiring nature which is closely related with individual’s behavior in the workplace. Banking sector is one of the sectors in Sri Lanka which makes a significant impact and contribution on community, society and the development of the economy of the country. It comprises of state and private banks, currently facing an intense competition. Every bank tries to ensure their quality service to customers. Job satisfaction of bankers is directly linked with service quality. This study aimed to identify the factors affecting employees’ job satisfaction level in private banking sector with special reference to Union Bank. Also the research was designed to identify the most significant factor which affects job satisfaction and to identify differences of job satisfaction level in different demographic groups. The independent variables of the study were pay, promotion and working conditions. The demographic groups considered based on gender, employment type and experience. A deductive approach was followed with quantitative data. Data was collected by using a questionnaire and it was done within a particular time period, the study was cross sectional in nature. Stratified sampling method was used, selected 200 employees. Data was analyzed with SPSS version 22. Descriptive statistics, correlation, regression and t-test and ANOVA were used. The results of the study showed that job satisfaction is strongly and positively correlated with working conditions and moderately positively correlated with pay, promotion. The most significant factor which affects job satisfaction was working conditions. A significant difference of job satisfaction level was observed only among groups with different experience levels. No significant differences of job satisfaction level were observed in different demographic groups based on gender and employment type. The findings contribute to the human resource practitioners at Union bank to develop human resource strategies in such a way it increases job satisfaction of bankers. Keywords: Banking sector, Job satisfaction, Pay, Promotion, Working condition

Who Moved Those Rain Clouds to Town? Making Windbirds to Learn about the Power of Wind

In this practical article, a kindergarten teacher shares a lesson designed to teach students about the power of wind. To address the Next Generation Science Standards engineering standards, students discussed the negative and positive aspects of wind and made daily weather observations (K-ESS2-1). Students constructed bird-shaped windsocks, called windbirds, to explore how the shape of the object allowed it to move in the wind (K-2-ETS1-2). To address the National Core Arts Standards, creative arts were integrated as students designed cylindrical windbirds of colorful materials. The windbirds were used to observe the effects of wind in the students’ outdoor environment at school. Students read both fiction and nonfiction books to increase their understanding of wind related concepts, learning how windmills can harness the power of the wind (K-ESS2-1). The article provides a review of related literature and a detailed plan of the lesson taught by the teacher

Moving Bed Biofilm Process in Activated Sludge Model 1 for Reject Water Treatment

A moving bed biofilm (MBB) process was modelled in AQUASIM using the standard activated sludge model 1 (ASM1) as a baseline. The model was controlled against experimental data from a pilot Hybrid Vertical Anaerobic Biofilm (HyVAB) reactor installed at Knarrdalstrand wastewater treatment plant, Porsgrunn, Norway. High ammonium concentration removal from reject water was studied by applying different aeration schemes at the plant and the modelling tool. Results show that the standard ASM1 model was poor to fit experimental data. Simulation results evidenced missing biochemical mechanisms related to anaerobic ammonium oxidation (Anammox) and short cut nitrogen removal processes. However, the essential simulation outputs are biofilm thickness, substrates concentration variation, and biomass distribution, partially validated with experimental results. The model, therefore, helped to realise the nature of the bioprocess observed at the pilot reactor.publishedVersio

Early breast cancer screening using iron/iron oxide-based nanoplatforms with sub-femtomolar limits of detection

Citation: Udukala, D. N., Wang, H. W., Wendel, S. O., Malalasekera, A. P., Samarakoon, T. N., Yapa, A. S., . . . Bossmann, S. H. (2016). Early breast cancer screening using iron/iron oxide-based nanoplatforms with sub-femtomolar limits of detection. Beilstein Journal of Nanotechnology, 7, 364-373. doi:10.3762/bjnano.7.33Additional Authors: Ortega, R.;Toledo, Y.;Bossmann, L.;Robinson, C.;Janik, K. E.;Koper, O. B.;Motamedi, M.;Zhu, G. H.Proteases, including matrix metalloproteinases (MMPs), tissue serine proteases, and cathepsins (CTS) exhibit numerous functions in tumor biology. Solid tumors are characterized by changes in protease expression levels by tumor and surrounding tissue. Therefore, monitoring protease levels in tissue samples and liquid biopsies is a vital strategy for early cancer detection. Water-dispersable Fe/Fe3O4-core/shell based nanoplatforms for protease detection are capable of detecting protease activity down to sub-femtomolar limits of detection. They feature one dye (tetrakis(carboxyphenyl) porphyrin (TCPP)) that is tethered to the central nanoparticle by means of a protease-cleavable consensus sequence and a second dye (Cy 5.5) that is directly linked. Based on the protease activities of urokinase plasminogen activator (uPA), MMPs 1, 2, 3, 7, 9, and 13, as well as CTS B and L, human breast cancer can be detected at stage I by means of a simple serum test. By monitoring CTS B and L stage 0 detection may be achieved. This initial study, comprised of 46 breast cancer patients and 20 apparently healthy human subjects, demonstrates the feasibility of protease-activity-based liquid biopsies for early cancer diagnosis

Shift-Volatility Transmission in East Asian Equity Markets

This paper attempts to provide evidence of "shift-volatility" transmission in the East Asian equity markets. By shift-volatility, we mean the volatility shifts from a low level to a high level, corresponding respectively to tranquil and crisis periods. We examine the interdependence of equity volatilities between Hong-Kong, Indonesia, Japan, Malaysia, the Philippines, Singapore, Thailand and the United States. Our main issue is whether shift-volatility needs to be considered as a regional phenomenon, or from a more global perspective. We find that the timing/spans of high volatility regimes correspond adequately to years historically documented as those of crises (the Asian crisis and the years following the 2008 crisis). Moreover, we suggest different indicators that could be useful to guide the investors in their arbitrage behavior in the different regimes: the duration of each state, the sensitivity of the volatility in a market following a change in the volatility in another market. Finally, we are able to identify which market can be considered as leading markets in terms of volatility

Process simulation for biogas upgrading and biomethane recovery using biofilm-based reactors

Microbial biofilm matrices offer numerous benefits in bioprocessing and are crucial in various industrial and remediation processes. They facilitate electron exchange from solid surfaces when they interact with the environment. Emerging technologies such as biofilm-containing trickle bed reactors (TBR) and bioelectrochemical systems (BESs) for carbon dioxide (CO2) utilization, mostly rely on microbial biofilm matrices. Metabolic modeling of biofilm-based reactors enables detailed analysis of CO2 reduction within microorganisms, enhancing reactor efficiency. This study employed simulation models to analyze biomethane synthesis within TBR and BES systems. AQUASIM simulation tool was used for conducting the simulation. Parameters such as non-stoichiometric and stoichiometric ratios of substrates, hydraulic retention time (HRT), biofilm surface area, and applied voltage in BES were varied to evaluate methane (CH4) production and microbial biomass growth in TBR and BES. Results demonstrated that 1 day HRT resulted in methanation process failure due to biomass development problem in both TBR and BES. The substrate ratio 1:4 of CO2 to H2 increased CH4 production in the investigated reactors. In BES, in-situ CO2 and proton (H+) generation from oxidation reactions can increase CH4 production. Whereas in TBR, external H2 (hydrogen) should be supplied to consume higher amount of CO2. The lag phase in TBR was shorter than that in BES because of the greater surface area in TBR. In BES, higher voltage increased the current generation because of development of more biomass on the cathode. The simulation underlines the influence of different variables on biofilm-based reactors, offering critical insights for experimental process design

Anaerobic digestion of biosolid pyrolysis liquid and hydrolyzed sludge - simulation with extended ADM1 model

Pyrolysis of biosolids aims to reduce solid volumes and improve energy recovery; however, the pyrolysis liquid (PL) is a by-product that has no good direct application. One idea is to link pyrolysis and anaerobic digestion (AD), in which PL can be valorized for methane production. PL contains various compounds that potentially threaten the stability of AD. This study, therefore, aims to extend the current Anaerobic Digestion Model No.1 (ADM1) and evaluate the influence of phenol, furfural, 5-hydroxymethylfurfural (5-HMF), styrene, and ammonia from PL on AD. Two lab-scale AD reactors were simulated and compared with experimental data: one fed with hydrolyzed sludge and the other fed with an additional stream of PL. The simulation accurately predicts hydrolyzed sludge as substrate, while the simulation of the reactor co-digesting hydrolyzed sludge and PL overestimates methane production. Ammonia, phenol, and styrene were identified as the most significant inhibitors. However, based on the overestimation of methane production, it is clear that the PL has more inhibitors present than those implemented in the model. Simulations further showed that an additional stream of PL increased methane production by 4.3%, even with significant inhibition by the compounds

A systematic quality assessment of Environmental Impact Statements in the oil and gas industry

The global economy relies heavily on oil and gas resources. However, hydrocarbon exploitation projects can cause significant impacts on the environment. But despite the production of numerous Environmental Impact Statements (EISs) to identify/mitigate such impacts, no study has specifically assessed the quality of EISs for both onshore and offshore oil and gas projects, with tested hypotheses. To address this research gap, our paper, for the first time, develops a modified Lee and Colley evaluation model to assess the quality of 19 sampled oil and gas project EISs produced from 1998 to 2008 in Nigeria. Our findings show that Project Description and Communication of Results are the main areas of strength. However, Environmental Impact Prediction, and Project Decommissioning, were among the key areas requiring attention. A key finding, though, is that Mann-Whitney tests suggest that there is no evidence that the quality of EISs for the latter period (2004–2008) is higher than that of the earlier period (1998–2004). We suggest that periodic systematic review of the quality of submitted/approved EISs (c. every 3–5 years) should be established to monitor trends in EIS quality and identify strong and weak areas. This would help to drive continual improvement in both the EIA processes and the resultant EISs of technical engineering projects. Such reviews have the potential to illuminate some of the underlying problems of, and solutions to, oil and gas exploration, production and transportation, and their related environmental impacts. This suggested change would also be useful internationally, including for the burgeoning exploration and production of unconventional hydrocarbon resources.Publisher Statement: NOTICE: this is the author’s version of a work that was accepted for publication in Science of The Total Environment. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Science of The Total Environment, [572, (2016)] DOI: 10.1016/j.scitotenv.2016.07.083© 2016, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0