School of Pure and Applied Sciences

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    SIMULATED MODELING: CONTRASTING Ca/Mg AND Mn+-NATURAL ORGANIC MATTER COMPETITIVE COMPLEXATION IN WATER
    (2015-07-20) Mbugua, John
    Complexing capacities of calcium and magnesium with natural organic matter (NOM)/selected organic chelating agents, in the presence and absence of other major and trace cations in water, were studied by anodic and cathodic square wave stripping voltammetry techniques (ASWSV and CSWSV). Under predetermined and optimized physico-chemical parameters (pH, temperature and ionic strength), calcium-NOM complexation and competitive complexation by other elements of known concentration (Pb, Zn, and Cu) were determined. Voltammetric measurements showed competition between calcium and the other cations for the binding sites of humic substances at depositing, measuring and equilibrating potential of -2V and +1V and scan time of 150seconds. Two systems were complexed by known concentrations of NOM fractions (Humic acid (HA), 1, 2-dihydroxybenzene (CAT/catechol) and tannic acid (TA)): Mn+-NOM; Mn+ Calcium-NOM complexes at different pH conditions. Results show significant differences in peak currents in the order Mn+> Ca/Mn+-TA/HA/CAT > Mn2+ TA/HA/CAT but differed depending on the metal species, type of humic chelant and pH. Visual Minteq and PHREEQC simulations show differences in distribution of scale causing species such as Ca2+, CaOH+, Mg2+ and MgOH+ that are highly dependent on the pH and concentration. This paper presents results of part of the work aimed at providing simulated modeling alternatives in combating scaling as a consequence of cooling water used in industry. It equally provides an assurance on the re-use of the scarce water resources by simulated water experiments and models
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    Decision quality: the impact of process redesign as an intangible, benefit on information technology investment decisions
    (2001) Atieno, Anne Ndede
    IT investment decisions often focus on tangible costs and benefits such as technical, strategic, and financial issues. Less tangible benefits such as process redesign integration, bave been largely ignored. Decisions makers who rely solely on these tangible costs and benefits for their assessment of IT investment value without integrating intangible benefit consideration may be making sub-optimal decisions and investments. This study looked at rhe important, yet often overlooked, intangible benefits consideration in the IT investment decision process with particular focus on process redesign as an intangible benefit. Survey questionnaires were sent out to a sample of 949 firms in three industries: healthcare, chemical, and insurance to solicit information from the chief information officer (CIo) on the level at which they integrate process redesign consideration in the IT inr-eshnent decision. Several important findings resulted from this research effort. First, the study irm"nr;fied seven component factors of process redesign and used these factors to measure the M of process redesign integration into the IT investment decision. Second, the study mfirmed, empirically, that there was an association between the consideration of tangible and intangible benefits. Those firms that expend large effort or resources towards tangible benef,rts consideration also spend more effort or resources toward intangible benefits consideration than otherwise. Third, it was empiricaliy determined that certain process redesign benefit factors received greater consideration than others. Fourth, it was determined #mr decision makers considered tangible benefits to be more important than intangible hmefits consideration and expended a greater portion of effort or resources towards the mideration of the former. Finally, this study found that the strategic relevance of IT in an orgAnization was associated with the level of effort or resoulce deployment towards inrangible benefits. Additional areas for further research were also identified.