150 research outputs found
The SF-36: a simple, effective measure of mobility disability for epidemiological studies
No full textBackgroundMobility disability is a major problem in older people. Numerous scales exist for the measurement of disability but often these do not permit comparisons between study groups. The physical functioning (PF) domain of the established and widely used Short Form-36 (SF-36) questionnaire asks about limitations on ten mobility activities.ObjectivesTo describe prevalence of mobility disability in an elderly population, investigate the validity of the SF-36 PF score as a measure of mobility disability, and to establish age and sex specific norms for the PF score.MethodsWe explored relationships between the SF-36 PF score and objectively measured physical performance variables among 349 men and 280 women, 59-72 years of age, who participated in the Hertfordshire Cohort Study (HCS). Normative data were derived from the Health Survey for England (HSE) 1996.Results32% of men and 46% of women had at least some limitation in PF scale items. Poor SF-36 PF scores (lowest fifth of the gender-specific distribution) were related to: lower grip strength; longer timed-up-and-go, 3m walk, and chair rises test times in men and women; and lower quadriceps peak torque in women but not men. HSE normative data showed that median PF scores declined with increasing age in men and women.ConclusionOur results are consistent with the SF-36 PF score being a valid measure of mobility disability in epidemiological studies. This approach might be a first step towards enabling simple comparisons of prevalence of mobility disability between different studies of older people. The SF-36 PF score could usefully complement existing detailed schemes for classification of disability and it now requires validation against them
Bassey Wai Andah and archaeological thought
No full textDuring the final years of his career, Bassey Andah served as the President of the World Archaeological Congress. His election to this post was in part a recognition of the crucial role of advocacy and leadership that he had adopted during the traumatic emergence of that organization, in the context of the struggle against apartheid in South Africa (Ucko 1987: 241). However, it can also be seen as reflecting the extraordinary contribution that Andah had made in thinking through what it meant to be a practicing archaeologist in a non-First World setting. By the time that the present author came to work with him in the capacity of WAC Secretary, he had undergone a unique intellectual odyssey, as a consequence of having first absorbed Euro-American archaeological thinking, and subsequently having reflected upon it from the perspective of the post-colonial African experience. His political commitments provided him with a source of critique that he was able to turn upon the theories and methodologies that had been employed in African archaeology, developing a distinctive perspective that grew progressively more radical and more profound
Bassey Wai Andah and archaeological thought
No full textDuring the final years of his career, Bassey Andah served as the President of the World Archaeological Congress. His election to this post was in part a recognition of the crucial role of advocacy and leadership that he had adopted during the traumatic emergence of that organization, in the context of the struggle against apartheid in South Africa (Ucko 1987: 241). However, it can also be seen as reflecting the extraordinary contribution that Andah had made in thinking through what it meant to be a practicing archaeologist in a non-First World setting. By the time that the present author came to work with him in the capacity of WAC Secretary, he had undergone a unique intellectual odyssey, as a consequence of having first absorbed Euro-American archaeological thinking, and subsequently having reflected upon it from the perspective of the post-colonial African experience. His political commitments provided him with a source of critique that he was able to turn upon the theories and methodologies that had been employed in African archaeology, developing a distinctive perspective that grew progressively more radical and more profound
Rice Husk as Precursor for Silicon Oxide Nanoparticles: Synthesis and Characterization
No full textAuthor: Nsikak Bassey Essien
Received: 19 April 2024/Accepted: 09 August 2024
Traditionally, SiONPs have been synthesized using conventional methods involving the use of toxic chemicals and high-energy processes. These methods raise concerns regarding environmental impact and production costs. In recent years, a growing emphasis has been placed on developing eco-friendly and cost-effective approaches for SiONP synthesis. Rice husk, a by-product of rice cultivation, represents a significant source of agricultural waste. It is estimated that over 100 million tons of rice husk are generated globally each year (Ahmad et al., 2011). This abundant waste material presents a compelling opportunity for the development of sustainable SiONP synthesis methods.Rice husk is a rich source of silica (SiO2), a key component of SiONPs. Notably, the silica content in rice husk can vary between 50-70% by weight, depending on the rice variety and geographical location (Ahmad et al., 2011). This inherent characteristic makes rice husk a promising bioresource for SiONP synthesi
Bassey Wai Andah and archaeological thought
No full textDuring the final years of his career, Bassey Andah served as the President of the World Archaeological Congress. His election to this post was in part a recognition of the crucial role of advocacy and leadership that he had adopted during the traumatic emergence of that organization, in the context of the struggle against apartheid in South Africa (Ucko 1987: 241). However, it can also be seen as reflecting the extraordinary contribution that Andah had made in thinking through what it meant to be a practicing archaeologist in a non-First World setting. By the time that the present author came to work with him in the capacity of WAC Secretary, he had undergone a unique intellectual odyssey, as a consequence of having first absorbed Euro-American archaeological thinking, and subsequently having reflected upon it from the perspective of the post-colonial African experience. His political commitments provided him with a source of critique that he was able to turn upon the theories and methodologies that had been employed in African archaeology, developing a distinctive perspective that grew progressively more radical and more profound
Analysis of upland farm households’ vulnerability to climate variability in the Niger Delta, Nigeria
No full textAnalysis of upland farm households’ vulnerability - Gabriel, Edet, *Valerie, Glory, Godwin, Clement, Nkoyo, E. Bassey and Obot
Analysis of upland farm households’ vulnerability to climate variability in the Niger Delta, Nigeria The study analysed the vulnerability of upland farm households to climate variability in the Niger Delta. Three states - Akwa Ibom, Ondo and Rivers were selected from the nine states that make up the Niger Delta region. A total of 120 respondents from upland communities of the Niger delta were used for analysis. Household questionnaire and vulnerability questionnaire using Cost Route method were the instruments used for data collection and analysed using Vulnerability Profile and Vulner-ability / Risk Framework. The results of the analysis show that both male and female headed house-holds in all the upland communities were vulnerable to flooding, windstorm, erosion and drying up of streams. Important factors that made households vulnerable to climate hazards were low agricultural output and income, non-availability of irrigation facilities, insufficient farm labour and lack of storage facilities. Technical capacities of household members were assessed using both science-based knowledge as well as indigenous knowledge of climate change as indicators to adaptation to climate variability. It was assumed that the adaptive capacity of households could be enhanced by the number of persons with either science-based knowledge or indigenous knowledge across the re-gion. Expenditure on carbohydrate was higher across the region during disaster time, followed by expenditure in protein, vitamin/minerals and fat and oil and other classes of food, implying that more carbohydrate food is consumed during disaster period than any other class of food. Certain geo-graphical factors such as distance to coastline and population have direct impact on climate variability in the Niger Delta Region. Recommendations include establishment of emergency evacuation systems, income opportunities and support programmes as well as capacity building on climate change knowledge, enterprise development and management.
Key words: Farm households, Nigeria, poverty, rural areas, smallholder farmer
Nigerian nationalism: a case study in southern Nigeria, 1885-1939
No full textModern Nigeria is a creation of the British who because of economic interest, ignored the existing political, racial, historical, religious and language differences. The task of developing a concept of nationalism from among such diverse elements who inhabit Nigeria and speak about 280 tribal languages was immense if not impossible. The traditionalists did their best in opposing the British who took away their privileges and traditional rights, but their policy did not countenance nationalism. The rise and growth of nationalism was only possible through educated Africans. Colonialism brought Nigeria in contact with the West and western culture, but the impact of it was felt differently in different parts of Nigeria. By debarring Christian Missions, lawyers and merchants the North, the British deliberately allowed Northern Nigeria to retain its customs and social structure. This further increased and complicated the problems of modernization, nationalism and unity, as Nigerians were influenced by two opposing outside cultures, .one Western, the other Oriental. The basic problems: social, racial and political were the result of the superstructure creation of Nigeria and they unmistakingly affect nationalism, as some of the ethnic groupings which make up Nigeria were large enough to constitute nations in themselves. Because of strong ethnocentrism existing in Nigeria, it has sometimes been argued that Nigeria bas not
one nationalism but many nationalisms. The educated elite have succeeded in winning statehood for Nigeria, but they have yet to succeed in bringing about cultural and political nationalism in Nigeria
Historic-Phenomenological Evaluation of the Christian Experience in the Threshold of Human Development in Nigeria
No full textInvestigation of corrosion of carbon steel under insulation
No full textCorrosion of metals under insulation is a serious concern for industries due to the fact that the insulation hides the metal from view which increases the likelihood of sudden failure. Carbon steel is one of the metal alloys frequently used in industries due to economic and technical reasons. However, it is quite susceptible to corrosion under insulation (CUI). The factors affecting corrosion of carbon steel under mineral wool insulation such as temperature, effectiveness of inhibitor, quantity and distribution of electrolyte in the insulation have not been extensively studied in the literature. In fact, studies on corrosion of metals under insulation are quite sparse compared to immersion (uninsulated) conditions. Therefore, the objectives of this study were to assess the effect of temperature (60 oC to 130 oC) on corrosion of carbon steel under insulation, effectiveness of a new commercial inhibitor (VpCI 619) in mitigating CUI of carbon steel, quantity and distribution of electrolyte (1wt. % NaCl) in mineral wool insulation as well as investigation of the drying times of the insulation using galvanic current and electrochemical impedance measurements. In addition, the prediction of CUI rate using Artificial Neural Network (ANN) was carried out with the aim of assessing the accuracy of prediction of different network parameters such as number of hidden layers, number of input parameters and choice of activation function. Prior to CUI studies, the water absorption capacity of mineral wool insulation was determined using standard procedures (ASTM C1511). This was carried out to assess the time it will take for the insulation to be saturated with water, the variability of repeated measurements as well as the total water content in the insulation. The CUI studies were carried out using a test rig that was based on ASTM G189-07 standard. The corrosion rates were estimated using weight loss technique and the effects of temperature, vapour phase inhibitor consisting primarily of sodium molybdate, quantity of electrolyte in insulation were investigated. The drying out profile of the insulation was assessed using galvanic current and electrochemical impedance measurements. Furthermore, the prediction of CUI rate was carried out using Artificial Neural Network and the effect of single and double hidden layers, sigmoid and hyperbolic tangent activation functions, as well as number of input parameters on accuracy of prediction of CUI rate were assessed. The results of the water absorption studies indicated continuous absorption of water even after immersion for 22 days. The water absorption capacity was greater for thermally treated insulation compared to untreated insulation samples due to thermal degradation of the oily additives and polymeric binders. The effect of temperature on CUI indicated an increase in corrosion rate from 60 oC to 80 oC. Further increase in temperature up to 130 oC resulted in a decrease in corrosion rate. The existence of a maximum point in the curve was attributed to the competing effects of two factors which include increased diffusivity of oxygen which dominates at low temperature and decreasing solubility of oxygen and insulation dry-out which dominates at temperatures exceeding 80 oC. The new commercial inhibitor was observed to mitigate the corrosion rate at the temperatures investigated in this study. The inhibition efficiency indicated an average of 89% when a dosage of 5.2 g/m2 of the inhibitor was used. The effectiveness was also observed to be dosage dependent with lower doses having less inhibition efficiency. The drying times of the insulation assessed using galvanic current and impedance methods were observed to decrease as temperature increased. The galvanic current was observed to decrease to zero while the impedance increased to high values as the insulation dries out. However, the drying times obtained from galvanic current method showed a higher variability compared to impedance method.The result of prediction of CUI rate using Artificial Neural Network indicated an increase in accuracy as the number of input parameters increased. Surprisingly, the accuracy of the predicted output from the four input parameters (temperature, dosage of inhibitor, quantity of electrolyte in insulation and sample position) was higher than the accuracy of the most influential parameters (temperature and dosage of inhibitor). This suggests that incorporation of more input parameters having some relationship with the output is more important in achieving a higher accuracy compared to usingthe most influential parameters only. In conclusion, this study indicated that mineral wool insulation absorbs water for a long period without saturation which increases the risk of CUI. Also, CUI rate increased with temperature up to 80 oC but decreased on further increase up to 130 oC. The newcommercial inhibitor was effective in mitigating CUI at the temperatures investigated. Also, more test solution was observed at the lower part of the insulation compared to the upper part when installed on the CUI test rig which increases the risk of severe corrosion at the lower section of the insulation. The prediction of CUI rate using ANN indicated that inclusion of more input parameters could improve prediction accuracy. Moreover, the choice of activation functions also has effect on the accuracy of the predicted output.Corrosion of metals under insulation is a serious concern for industries due to the fact that the insulation hides the metal from view which increases the likelihood of sudden failure. Carbon steel is one of the metal alloys frequently used in industries due to economic and technical reasons. However, it is quite susceptible to corrosion under insulation (CUI). The factors affecting corrosion of carbon steel under mineral wool insulation such as temperature, effectiveness of inhibitor, quantity and distribution of electrolyte in the insulation have not been extensively studied in the literature. In fact, studies on corrosion of metals under insulation are quite sparse compared to immersion (uninsulated) conditions. Therefore, the objectives of this study were to assess the effect of temperature (60 oC to 130 oC) on corrosion of carbon steel under insulation, effectiveness of a new commercial inhibitor (VpCI 619) in mitigating CUI of carbon steel, quantity and distribution of electrolyte (1wt. % NaCl) in mineral wool insulation as well as investigation of the drying times of the insulation using galvanic current and electrochemical impedance measurements. In addition, the prediction of CUI rate using Artificial Neural Network (ANN) was carried out with the aim of assessing the accuracy of prediction of different network parameters such as number of hidden layers, number of input parameters and choice of activation function. Prior to CUI studies, the water absorption capacity of mineral wool insulation was determined using standard procedures (ASTM C1511). This was carried out to assess the time it will take for the insulation to be saturated with water, the variability of repeated measurements as well as the total water content in the insulation. The CUI studies were carried out using a test rig that was based on ASTM G189-07 standard. The corrosion rates were estimated using weight loss technique and the effects of temperature, vapour phase inhibitor consisting primarily of sodium molybdate, quantity of electrolyte in insulation were investigated. The drying out profile of the insulation was assessed using galvanic current and electrochemical impedance measurements. Furthermore, the prediction of CUI rate was carried out using Artificial Neural Network and the effect of single and double hidden layers, sigmoid and hyperbolic tangent activation functions, as well as number of input parameters on accuracy of prediction of CUI rate were assessed. The results of the water absorption studies indicated continuous absorption of water even after immersion for 22 days. The water absorption capacity was greater for thermally treated insulation compared to untreated insulation samples due to thermal degradation of the oily additives and polymeric binders. The effect of temperature on CUI indicated an increase in corrosion rate from 60 oC to 80 oC. Further increase in temperature up to 130 oC resulted in a decrease in corrosion rate. The existence of a maximum point in the curve was attributed to the competing effects of two factors which include increased diffusivity of oxygen which dominates at low temperature and decreasing solubility of oxygen and insulation dry-out which dominates at temperatures exceeding 80 oC. The new commercial inhibitor was observed to mitigate the corrosion rate at the temperatures investigated in this study. The inhibition efficiency indicated an average of 89% when a dosage of 5.2 g/m2 of the inhibitor was used. The effectiveness was also observed to be dosage dependent with lower doses having less inhibition efficiency. The drying times of the insulation assessed using galvanic current and impedance methods were observed to decrease as temperature increased. The galvanic current was observed to decrease to zero while the impedance increased to high values as the insulation dries out. However, the drying times obtained from galvanic current method showed a higher variability compared to impedance method.The result of prediction of CUI rate using Artificial Neural Network indicated an increase in accuracy as the number of input parameters increased. Surprisingly, the accuracy of the predicted output from the four input parameters (temperature, dosage of inhibitor, quantity of electrolyte in insulation and sample position) was higher than the accuracy of the most influential parameters (temperature and dosage of inhibitor). This suggests that incorporation of more input parameters having some relationship with the output is more important in achieving a higher accuracy compared to usingthe most influential parameters only. In conclusion, this study indicated that mineral wool insulation absorbs water for a long period without saturation which increases the risk of CUI. Also, CUI rate increased with temperature up to 80 oC but decreased on further increase up to 130 oC. The newcommercial inhibitor was effective in mitigating CUI at the temperatures investigated. Also, more test solution was observed at the lower part of the insulation compared to the upper part when installed on the CUI test rig which increases the risk of severe corrosion at the lower section of the insulation. The prediction of CUI rate using ANN indicated that inclusion of more input parameters could improve prediction accuracy. Moreover, the choice of activation functions also has effect on the accuracy of the predicted output
Design and the implementation of a lexical analyzer for Ada programming language, 1985
No full textThe title of this thesis is 'The design and the implementation of a lexical analyzer for the Ada programming language'. Hence this paper describes my procedures for performing this design and implementation. The lexical analyzer I am refering to is a computer program which performs lexical analysis for any program written in Ada. A detailed description of the steps involved in designing this program is given in all the chapters of this paper
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