Design of fuel efficient brick kiln for ceramic water filter firing in Ghana

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007."June 2007."Includes bibliographical references (p. 104-105).Ceramic water filters are currently produced in Ghana in order to provide a household solution to contaminated water. These filters, locally branded with the name Kosim filter by originating from Potters for Peace-Nicaragua, are heated using a generic kiln that is not attuned to the filters' current characteristics. The need for water filters is currently greatest in Northern Ghana, where more than one million people do not have access to safe water, but filter production occurs in Southern Ghana. A custom kiln will strengthen the filters, increase the filter's survival rate, and eliminate the need to transport the filters. Additionally, the traditional fuel source, wood, is extremely scarce, thus indicating the need for a more fuel efficient method of firing the kiln. Our thesis focuses on evaluating prior kilns built in developing countries and designing a fuel efficient kiln for Northern Ghana, where a kiln does not currently exist and fuel is scarce.by Eric Adjorlolo and Silpa Kaza.S.B

Some Conditions That Affect Practical Application of Factor Analysis

The study examined some conditions that must be satisfied in order to perform Factor Analysis. The objective was to determine whether or not the accepted pre-requisite tests always prove that the dataset will produce practical factor solution. Some of the conditions examined are the Kaiser-Meyer-Olkin test of sampling adequacy and the Bartlett’s test of sphericity. Two datasets were used in this study namely Sales Performance and Personality Types. Both datasets were subjected to the pre-requisite tests and the extraction of various factor solutions. Both datasets passed the pre-requisite tests. One of the datasets was found not to produce significant factor solution; the other produced a practical factor solution. Keywords: factor analysis, Kaiser-Meyer-Olkin test, Bartlett’s tes

Estimating woody vegetation cover in an African Savanna using remote sensing and geostatistics.

Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.A major challenge in savanna rangeland studies is estimating woody vegetation cover and densities over large areas where field based census alone is impractical. It is therefore crucial that the management and conservation oriented research in savannas identify data sources that provides quick, timely and economical means to obtain information on vegetation cover. Satellite remote sensing can provide such information. Remote sensing investigations, however, require establishing statistical relationships between field and remotely sensed data. Usually regression is the empirical method applied to field and remotely sensed data for the spatial estimation of woody vegetation variables. Geostatistical techniques, which take spatial autocorrelation of variables into consideration, have rarely been used for this purpose. We investigated the possibility of improving woody biomass predictions in tropical savannas using cokriging. Cokriging was used to evaluate the cross-correlated information between SPOT (Satellites Pour l’Observation de la Terre or Earth-observing Satellites)-derived vegetation variables and field sampled woody vegetation percentage canopy cover and density. The main focus was to estimate woody density and map the distribution of woody cover in an African savanna environment. In order to select the best SPOT-derived vegetation variable that best correlate with field sampled woody variables, several spectral vegetation and texture indices were evaluated. Next, variogram models were developed: one for woody canopy cover and density, one for the best SPOT-derived vegetation variable, and a crossvariogram between woody variables and best SPOT-derived data. These variograms were then used in cokriging to estimate woody density and map its spatial distribution. Results obtained indicate that through cokriging, the estimation accuracy can be improved compared to ordinary kriging and stepwise linear regression. Cokriging therefore provided a method to combine field and remotely sensed data to accurately estimate woody cover variables

Remote sensing of the distribution and quality of subtropical C3 and C4 grasses.

Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.Global climate change is expected to be accompanied by changes in the composition of plant functional types. Such changes are predicted to follow shifts in the percentage cover and abundance of grass species, following the C3 and C4 photosynthetic pathways. These two groups differ in a number of physiological, structural and biochemical aspects. It is important to measure these characteristic properties because they affect ecosystem processes, such as nutrient cycling. High spectral and spatial resolution remote sensing systems have been proven to offer data, which can be used to accurately detect, classify and map plant species. The major challenge, however, is that the spectral reflectance data obtained over many narrow contiguous channels (i.e. hyperspectral data) represent multiple classes that are often mixed for a limited training-sample size. This is commonly referred to as the Hughes phenomenon or “the curse of dimensionality”. In the context of hyperspectral data analysis, the Hughes phenomenon often introduces a high degree of multicollinearity, which is caused by the use of highly-correlated spectral predictors. Multicollinearity is a prominent problem in processing hyperspectral data for vegetation applications, due to similarities in the spectral reflectance properties of biophysical and biochemical attributes. This study explored an innovative method to solve the problems associated with spectral dimensionality and the related multicollinearity, by developing a user-defined inter-band correlation filter function to resample hyperspectral data. The proposed resampling technique convolves the spectral dependence information between a chosen band-centre and its shorter and longer wavelength neighbours. The utility of the new resampling technique was assessed for discriminating C3 (Festuca costata) and C4 (Themeda triandra and Rendlia altera) grasses and for predicting their nutrient content (nitrogen, protein, moisture, and fibre), using partial least squares and random forest regressions. In general, results obtained showed that the user-defined inter-band correlation filter technique can mitigate the problem of multicollinearity in both classification and regression analyses. Wavebands in the shortwave infrared region were found to be very important in regression and classification analyses, using field spectra-only datasets. Next, the analyses were up-scaled from field spectra to the new generation multispectral satellite, WorldView-2 imagery, which was acquired for the Cathedral Peak region of the Drakensberg Mountains. The results obtained, showed that the WV2 image data contain useful information for classifying the C3 and C4 grasses and for predicting variability in their nitrogen and fibre concentrations. This study makes a contribution by developing a user-defined inter-band correlation filter to resample hyperspectral data, and thereby mitigating the high dimensionality and multicollinearity problems, in remote sensing applications involving C3 and C4 grass species or communities

"I don't want financial support but verbal support." How do caregivers manage children's access to and retention in HIV care in urban Zimbabwe?

INTRODUCTION: Children living with HIV experience particular challenges in accessing HIV care. Children usually rely on adult caregivers for access to care, including timely diagnosis, initiation of treatment and sustained engagement with HIV services. The aim of this study was to inform the design of a community-based intervention to support caregivers of HIV-positive children to increase children's retention in care as part of a programme introducing decentralized HIV care in primary health facilities. METHODS: Using an existing conceptual framework, we conducted formative research to identify key local contextual factors affecting children's linkages to HIV care in Harare, Zimbabwe. We conducted semi-structured interviews with 15 primary caregivers of HIV-positive children aged 6-15 years enrolled at a hospital clinic for at least six months, followed by interviews with nine key informants from five community-based organizations providing adherence support or related services. RESULTS: We identified a range of facilitators and barriers that caregivers experience. Distance to the hospital, cost of transportation, fear of disclosing HIV status to the child or others, unstable family structure and institutional factors such as drug stock-outs, healthcare worker absenteeism and unsympathetic school environments proved the most salient limiting factors. Facilitators included openness within the family, availability of practical assistance and psychosocial support from community members. CONCLUSIONS: The proposed decentralization of HIV care will mitigate concerns about distance and transport costs but is likely to be insufficient to ensure children's sustained retention. Following this study, we developed a package of structured home visits by voluntary lay workers to proactively address other determinants such as disclosure within families, access to available services and support through caregivers' social networks. A randomized controlled trial is underway to assess impact on children's retention in care over two years

The Impact of Harvest Frequency on Herbage Yield and Quality of Cynodon nlemfuensis

Ruminants in Ghana experience feed deficit in the dry season leading to loss of weight and condition. To curb this problem of weight loss, there is the need to raise their plain of nutrition in the critical months of the year when feed is low in quantity and quality. This can be achieved by maximising forage production through appropriate harvest management practices. This study sought to find the effect of repeated harvest on dry matter (DM) yield of Cynodon nlemfuensis (Cynodon) in the coastal savanna of Ghana. It was hypothesised that infrequent repeated harvest will improve DM yield and nutritive value of Cynodon. An area of 7.0 m by 5.5 m was used for a two year study (2013 and 2014). The treatments were harvest of Cynodon at 24 (T1), 12 (T2) and 6 (T3) weeks intervals. The Randomised Complete Block Design was used with four replicates per treatment. Dry matter yield and plant cell wall constituents viz. NDF, ADF and Cellulose contents decreased significantly (P < 0.05) in the order T3<T2<T1, indicating that DM yield and plant cell wall constituents decreased with increasing harvest frequency. Crude protein content (CP) decreased significantly (P < 0.05) in the order T1<T2<T3, indicating that CP content increased with increasing harvest frequency. The study has shown that repeated harvest of Cynodon provided lower DM yield of better quality, with harvest at six weeks interval exceeding the minimum CP level required for adequate intake and digestibility by ruminant livestock

Validation of the multidimensional WHOQOL-OLD in Ghana: A study among population-based healthy adults in three ethnically different districts

Objectives: Study of well-being of older adults, a rapidly growing demographic group in sub-Saharan Africa, depends on well-validated tools like the WHOQOL-OLD. This scale has been tested on different populations with reasonable validity results but has limited application in Africa. The specific goal of this paper was to examine the factor structure of the WHOQOL-OLD translated into three Ghanaian languages: Ga, Akan, and Kasem. We also tested group invariance for sex and for type of community (distinguished by ethnicity/language). Methods: We interviewed 353 older adults aged 60 years and above, selected from three ethnically and linguistically different communities. Using a cross-sectional design, we used purpose and convenience methods to select participants in three geographically and ethnically distinct communities. Each community was made up of selected rural, peri-urban, and urban communities in Ghana. The questionnaire was translated into three languages and administered to each respondent. Results: The results showed moderate to high internal consistency coefficient and factorial validity for the scale. Using confirmatory factor analysis, we found that the results supported a multidimensional structure of the WHOQOL-OLD and that it did not differ for males and females, neither did it differ for different ethnic/linguistic groups. Conclusions: We conclude that the translated versions of the measure are adequate tools for evaluation of quality of life of older adults among the respective ethnic groups studied in Ghana. These results will also enable comparison of quality of life between older adults in Ghana and in other cultures

When new technology is an answer for old problems: the use of videoconferencing in cognitive aging assessment

People living with cognitive impairment and dementia require regular screening of their symptomatology and needs. Brief cognitive screening is crucial for assessing these conditions. Such screening can give health professionals a snapshot of the patient’s cognitive abilities and help in their monitoring and adaptation. An appropriate administration of brief cognitive screening using telemedicine technology, such as videoconference, can improve access to care and treatment planning. Moreover, the burden that rural and underserved communities often suffer because of limited access to specialty mental health services is also of concern. Herein, in this review, we describe the existing and relevant research regarding the administration of neuropsychological instruments via videoconferencing, and suggest methodological improvements for further studies. To date, only a handful of scientific studies have been published documenting the feasibility and acceptability of videoconferencing among older people and health professionals. Varying in their assessment tools, the studies demonstrate the reliability of cognitive testing and clinical diagnosis of dementia via videoconferencing, as noted by the associations between results of several cognitive tests using it as compared to face-to-face interviews. Further research is required to replicate findings and bring new solutions for their adaptation to a wide range of individuals, health professionals, areas of practice and settings.info:eu-repo/semantics/publishedVersio

A review of the catalytic oxidation of carbon-carbon composite aircraft brakes

This document is the Accepted Manuscript version, made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/. The final, definitive version of this paper is available online at doi: https://doi.org/10.1016/j.carbon.2015.08.100.The use of de-icing chemicals at airport runways has been shown to produce oxides and carbonates of sodium, potassium and calcium which catalyse the oxidation of carbon-carbon composite aircraft brakes leading to an increase of the oxidation rate by an order of magnitude. This review reports on studies that have characterised the catalytic oxidation and discusses the mechanism of the catalytic reaction based on investigations that were carried out with both C-C composites and carbon as a fossil fuel. The alkali metal oxides/carbonates are more active catalysts and in their case, the redox reaction between the monoxides and the peroxides has been identified as the most likely catalysis mechanism. In order to reduce or eliminate the problem of catalysis, doping with boron or phosphorus compounds has been investigated by a number of researchers. The effect of these along with the use of protective coatings is also reviewed.Peer reviewe

Seasonal Changes in Chemical Composition, Preference and In Sacco Degradation of Eight Different Fodder Tree leaves

Livestock farmers in the Coastal Savannah of Ghana cut and feed leaves of various naturally occurring fodder tree species to supplement livestock diets, especially in the dry season. The aim of this study was to determine the seasonal changes in chemical composition, rumen degradation characteristics and preference of sheep for eight common indigenous fodder tree leaves, and ascertain their contribution to livestock production. Fodder leaves from Albizzia lebbek (AL), Baphia nitida (BN), Blighia sapida (BS), Ficus exasperata (FE), Ficus polita (FP), Morinda lucida (ML), Moringa oleifera (MO) and Spondias mombin (SM) were used. Fresh leaves were sampled in the wet and dry seasons to determine changes in seasonal chemical composition. Four Djallonke sheep (two males and two females) of average weight of 27.3 kg ±0.22 were offered fresh fodder leaves in a cafeteria system to determine preference. In sacco dry matter (DM) degradation was determined using four fistulated sheep in a repeated atin suare design. Seasonal D crude protein C acid detergent fire D neutral detergent fire D and lignin content of the fodder leaves ranged fro 319.7 to 862.7 g kg-1, 150.0 to 359.2 g kg -1 D . to . g g -1 DM , 277.5 to 718.3 g kg -1 DM and . to . g g-1 DM respectively. Crude protein content of, AL and FP were higher for the wet season than dry season but BS had similar trend for both seasons. The soluble and potentially degradable fractions of D ranged from 113.3-216.8 and 142.9-627.7 g kg-1. It is concluded that the four most preferred fodder species were AL, FE, SM and MO. Their CP contents regardless of the season were higher than the minimum level considered as adeuate for oderate ruinant production. t is epected that these fodder leaves ill contriute to ypass protein and nitrogen retention and suseuently lead to eight gain hen fed to sheep