No description available.

Microbial fuel cells (MFCs) are potentially advantageous as an energy-efficient approach to wastewater treatment. For single-chamber tubular MFCs, anode effluent is used as catholyte instead of tap water or buffer solutions. Therefore, exposing cathode electrode to atmosphere could be also considered as a passive aeration for further aerobic oxidation of organics and nitrification. Based on several bench-scale studies, a 200-L scale MFC system with passive aeration process has been developed for treating actual municipal wastewater after primary clarification. The integrated system was able to remove over 80% organic contaminants and solid content from primary effluent. Through parallel and serial electricity connection, the power output of ~200 mW and the conversion efficiency of ~80% for charging capacitors were achieved by using commercially available energy harvesting device (BQ 25504). The treatment system is energy-efficient for the energy saving from aeration and sludge treatment while partial energy recovery as direct electricity can be utilized on site to power small electric devices. However, the post treatments are required to polish the effluent for nutrients removal. / Ph. D.

By positioning within an alternative development and agency/actor-oriented perspectives, and by employing diverse qualitative research methods, this study examines the dynamics of community self-help development and scaling up. The study investigates the processes and factors that contribute to successful community self-help development that leads to community capacity and empowerment. The diverse processes, through which poor people, through their individual and collective agency, strategize their actions, resist and negotiate with other stakeholders is emphasised. Community’s own mobilization for self-management, based on the networks of self-help groups; trusted leadership drawn from community members with excellent mobilization skill to spark community’s own mobilization for empowerment; poor people’s collective agency; trust that builds community and promotes collective actions; genuine participation within the community, which is realized because of planned and spontaneous interaction among intimate, small groups of people; and outside supports from government and NGOs, based on the bottom up proposals of communities are the main processes and elements of successful community self-help development. On the other hand, the study has shown that the scaling up of such successful community self-help development in Ethiopia is constrained by unfavourable institutional arrangements within the government structures, lack of capacity and power among local governments and inescapable nominal and instrumental participation, rather than genuine participation to build local people’s capability. Methodological limitations and lack of awareness about the goal of scaling up within the existing replication efforts are other challenges of scaling up. The researcher argues that the existing institutions and participatory practices may present opportunities for a gradual actualization of people’s agency, because the poor are capable of formulating new ways of strategizing and combining available resources in a new manner to solve problems. Thus, by using the available, small opportunity and systematically combining with other grassroots development approaches, by emphasizing on small, intimate groups of people (community/village), alternative spaces of scaling up can be identified and used.

The thesis empirically examined the implications of microfinance scaling up or sustainability on outreach in Nigeria. Basically, two methodologies were used namely, panel data econometric and survey methods. The panel dataset of 752 microfinance banks in Nigeria was used during the period 2011-2014, while the survey was conducted on some selected microfinance banks in Federal Capital Territory, Abuja in 2014. The findings from the thesis showed that, at the national level, yield, labour cost, orientation, efficiency, gender and size of loans are the major drivers of microfinance banks‟ sustainability in Nigeria. While at the state level, microfinance banks sustainability is driven by orientation and loan size. Findings also showed that sustainable MFBs tend to be more focused on the poor clients. The thesis showed that lending to female clients improves repayment rate of MFBs in Nigeria. Corroborating the regression result, the survey findings also suggest that lending to women had improved and enhanced repayment rate. In view of these findings, the thesis recommends that sustainability and outreach are not necessarily incompatible. However in pursuing sustainability greater attention should be on female clients, as greater lending to women would improve the repayment rate of MFBs and further engendered the industry sustainability.

Background. Developing countries are undergoing a process of epidemiological transition from infectious to non-communicable diseases, described by the United Nations Secretary General Ban Ki-Moon as “a public health emergency in slow motion”. One of the most prevalent of these diseases, in sub-Saharan Africa, is hypertension, which is a complex chronic condition often referred to as the “silent killer” and a key contributor to the development of cardiovascular and cerebrovascular diseases. Hypertensive patients in this setting are estimated to increase from 74.7 million in 2008 to 125.5 million in 2025, a 68% increase. There is however an important gap between emerging high-level policies and recommendations, and the near-absence of practical guidance and experience delivering long-term medical care for non-communicable diseases within resources-limited health systems. To address this gap, our study consisted of field investigations to determine the minimum health systems requirements necessary to ensure successful delivery of anti-hypertensive medications when scaling-up interventions. Methods/Design. A cross-sectional analytic study was conducted in the Western Cape Province of South Africa using a mixed method approach with two sets of semi-structured interviews and simulation modeling. One set of interviews was conducted with health professionals involved in the care of hypertensive patients within nine community health centers (five urban and four rural) to understand the challenges associated with their care. The other set was used to map and assess the current supply chain management system of antihypertensive medications and involved key informants at different levels of the process. Finally, modeling and simulation tools with ARENA Software were used to estimate minimum numbers of health workers required to ensure successful delivery of medications when scaling up interventions. Results. The study found numerous challenges affecting the care of hypertensive patients in primary health care facilities and categorized these into five interconnected dimensions: Management of the visits within the PHC facility, Adequacy of human resources, Standardization of patients’ care, Infrastructure limitations, and Patients’ responsibilities. Potential solutions to overcome these challenges were explored in order to improve the care of the hypertensive patients in the PHC facilities. Mapping of the drug supply chain management system highlighted the complexity of the system. In fact many of the issues reported fell outside of the control of the provincial health department. The need for a more single comprehensive computer system to handle most of the functions of the drug supply management system was heavily emphasized. The modeling and simulation tool with ARENA Software estimated the type and number of health care professionals needed to provide appropriate services to a certain patient population based on the set targets. The sample data used showed how one can test the impact of various changes in the processes and staffing levels to minimize waiting times while increasing the daily patients’ intake at the facility. We found that with few additional nursing staff, that are more affordable and quicker to train than medical doctors and pharmacists, one can considerably improve the performance of the facilities in the care of hypertensive patients. Discussion. This investigation has highlighted the detailed processes in place for the care of hypertensive patients in primary health care facilities, identifying the challenges in providing such care. The potential solutions suggested by the study results, if implemented, should help improve services offered and ensure that the system remains sustainable when patients’ intake increases exponentially as a result of scaled up interventions. The weaknesses of the drug supply chain management system demand immediate action. The modeling and simulation tools used in this study, if used on an ongoing basis, could create more effective planning of needed resources, although their proper utilization will require extra training for managers. Whether there is sufficient political support to ensure the resources necessary to reach the provincial health department’s hypertension target remains to be seen, and would benefit with further economic studies to estimate the cost associated with tackling the hypertension epidemic.

Continuous wet granulation using a twin-screw extruder has attracted considerable attentions in pharmaceutical industry as it ensures consistent tablet quality at a high production rate. However, challenge still exists in controlling desired granule properties especially when different sized twin-screw granulators are used. This study therefore explored the potential of scalability of two sized twin-screw extruders and the how raw materials affect granules properties in two twin-screw extruders. The first study focuses on aspects of scaling using two twin-screw extruders, 18mm and 27mm. Dimensionless groups including Fr Number, Powder Feed Number and Degree of Fill (<30%) were studied to observe their influences on granule attributes. It was found that these dimensionless groups demonstrated inconsistent effects on granule properties and the effect of Powder Feed Number was highly dependent on Degree of Fill. Different extruder still exerts significant impact on granule properties. A scaling rule was established for median granule size (d50) only, but only moderate degree of fit was found. Although a considerable number of studies have been published on controlled-release and extended-release excipients, little attentions have been given to the influence of microcrystalline cellulose (MCC) grades in twin-screw wet granulation. The second study therefore investigated the processability of five grades MCC from the Avicel® PH family using two twin-screw extruders again, 18mm and 27mm. Granule attributes including particle size, density, moisture, and strength were tested and it was found that MCC inherent density has the most significant impact on granule properties while particle size of MCC has minor positive effect on granule size. This study also concluded that better granule flowability and uniformity can be achieved by using low moisture, larger particle size and high density MCC as excipients. / Thesis / Master of Applied Science (MASc)

The thesis empirically examined the implications of microfinance scaling up or sustainability on outreach in Nigeria. Basically, two methodologies were used namely, panel data econometric and survey methods. The panel dataset of 752 microfinance banks in Nigeria was used during the period 2011-2014, while the survey was conducted on some selected microfinance banks in Federal Capital Territory, Abuja in 2014. The findings from the thesis showed that, at the national level, yield, labour cost, orientation, efficiency, gender and size of loans are the major drivers of microfinance banks‟ sustainability in Nigeria. While at the state level, microfinance banks sustainability is driven by orientation and loan size. Findings also showed that sustainable MFBs tend to be more focused on the poor clients. The thesis showed that lending to female clients improves repayment rate of MFBs in Nigeria. Corroborating the regression result, the survey findings also suggest that lending to women had improved and enhanced repayment rate. In view of these findings, the thesis recommends that sustainability and outreach are not necessarily incompatible. However in pursuing sustainability greater attention should be on female clients, as greater lending to women would improve the repayment rate of MFBs and further engendered the industry sustainability.

No description available.

Semi-batch crystallization experiments have been performedboth in a loop reactor and in stirred tank reactors.Hydrochloric acid was fed to a stirred solution of sodiumbenzoate, and benzoic acid immediately formed. Benzoic acid isformed in excess of the solubility making the solutionsupersaturated. The loop reactor is U-shaped. In one leg a propeller stirrerwas placed to circulate the solution and in the other a turbinestirrer was placed in front of the feed point to vary the localmixing intensity. The objective was to analyse the relativeimportance of different levels of mixing on the product sizedistribution. The importance of mixing as well as scaling-upeffects on the product size distribution were studied in threestirred tank reactors of volumes 2.5 L, 10 L, and 200 L. Thestirred tank reactors had different geometry and were equippedwith either a marine propeller or a pitched blade turbine. The weight mean size generally increases with increasingtotal feeding time and increasing mixing intensity. The weightmean size increases by locating an extra turbine impeller atthe feed point in the 10 L stirred tank reactor. The turbineimpeller provides the desired feed point mixing intensitywithout raising the mixing intensity of the whole tank. The weight mean size increases with decreasing feed pipediameter in the loop reactor and for low feed rates in the 10 Lstirred tank reactor. The weight mean size increasessignificantly by changing the feed pipe opening from circularto rectangular with a constant cross-sectional area at equalfeed rates. Backmixing is visually observed in the largest feedpipe diameter in the loop reactor, thus, reducing the weightmean size. However, backmixing is not considered to be adominant phenomenon in the present work. Mesomixing time constants have been calculated according tothe turbulent dispersion mechanism and the inertial-convectivemechanism. The time constants for mesomixing are generallylonger than the time constant for micromixing. Thus, the ratioof the mesomixing and the micromixing time constants shows aninfluence of mesomixing as is shown by the experimentalresults. The experimental results are best described by theinertial-convective disintegration mechanism showing that thefeed plume mixing increases with decreasing feed pipe diameterand increased feed point mixing. The weight mean size is not strongly affected by the reactorvolume. However, the mixing conditions in the reactors have astrong influence on the weight mean size. No suggestedscaling-up rule can satisfactorily predict the weight mean sizein the different volumes. No single physical parameter, such asthe local energy dissipation rate, the mean energy dissipationrate or the circulation time, can satisfactorily explain theexperimental results. A new dimensionless mixing parameter, TR,has been defined as the ratio of the total feeding time and themesomixing time constant. The mesomixing time constant isdefined as the shortest dimension of the feed pipe divided bythe resultant bulk velocity passing the feed pipe entrance. Theexperimental results from both the loop reactor and the stirredtank reactors of different volumes can be correlated with TR.The weight mean size increases with increasing TR. <b>Keywords</b>: reaction crystallization, precipitation,benzoic acid, macromixing, mesomixing, micromixing,semi-batch, loop reactor, backmixing, colour experiments,scaling-up. <b>Keywords</b>: reaction crystallization, precipitation,benzoic acid, macromixing, mesomixing, micromixing,semi-batch, loop reactor, backmixing, colour experiments,scaling-up.

<p>Semi-batch crystallization experiments have been performedboth in a loop reactor and in stirred tank reactors.Hydrochloric acid was fed to a stirred solution of sodiumbenzoate, and benzoic acid immediately formed. Benzoic acid isformed in excess of the solubility making the solutionsupersaturated.</p><p>The loop reactor is U-shaped. In one leg a propeller stirrerwas placed to circulate the solution and in the other a turbinestirrer was placed in front of the feed point to vary the localmixing intensity. The objective was to analyse the relativeimportance of different levels of mixing on the product sizedistribution. The importance of mixing as well as scaling-upeffects on the product size distribution were studied in threestirred tank reactors of volumes 2.5 L, 10 L, and 200 L. Thestirred tank reactors had different geometry and were equippedwith either a marine propeller or a pitched blade turbine.</p><p>The weight mean size generally increases with increasingtotal feeding time and increasing mixing intensity. The weightmean size increases by locating an extra turbine impeller atthe feed point in the 10 L stirred tank reactor. The turbineimpeller provides the desired feed point mixing intensitywithout raising the mixing intensity of the whole tank.</p><p>The weight mean size increases with decreasing feed pipediameter in the loop reactor and for low feed rates in the 10 Lstirred tank reactor. The weight mean size increasessignificantly by changing the feed pipe opening from circularto rectangular with a constant cross-sectional area at equalfeed rates. Backmixing is visually observed in the largest feedpipe diameter in the loop reactor, thus, reducing the weightmean size. However, backmixing is not considered to be adominant phenomenon in the present work.</p><p>Mesomixing time constants have been calculated according tothe turbulent dispersion mechanism and the inertial-convectivemechanism. The time constants for mesomixing are generallylonger than the time constant for micromixing. Thus, the ratioof the mesomixing and the micromixing time constants shows aninfluence of mesomixing as is shown by the experimentalresults. The experimental results are best described by theinertial-convective disintegration mechanism showing that thefeed plume mixing increases with decreasing feed pipe diameterand increased feed point mixing.</p><p>The weight mean size is not strongly affected by the reactorvolume. However, the mixing conditions in the reactors have astrong influence on the weight mean size. No suggestedscaling-up rule can satisfactorily predict the weight mean sizein the different volumes. No single physical parameter, such asthe local energy dissipation rate, the mean energy dissipationrate or the circulation time, can satisfactorily explain theexperimental results. A new dimensionless mixing parameter, TR,has been defined as the ratio of the total feeding time and themesomixing time constant. The mesomixing time constant isdefined as the shortest dimension of the feed pipe divided bythe resultant bulk velocity passing the feed pipe entrance. Theexperimental results from both the loop reactor and the stirredtank reactors of different volumes can be correlated with TR.The weight mean size increases with increasing TR.</p><p><b>Keywords</b>: reaction crystallization, precipitation,benzoic acid, macromixing, mesomixing, micromixing,semi-batch, loop reactor, backmixing, colour experiments,scaling-up.</p><p><b>Keywords</b>: reaction crystallization, precipitation,benzoic acid, macromixing, mesomixing, micromixing,semi-batch, loop reactor, backmixing, colour experiments,scaling-up.</p>