148 research outputs found

    Impediments to the Growth of Information and Communication Technologies in Africa’s Least Developed Countries, LDCs

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    The paper under took a critical examination of the impediments to the growth of the ICTs in Africa’s Least Developed Countries, LDCs. It began by exploring the “window of opportunities” ICTs hold for the LDCs. The paper however argued that these benefits can only touch on the lives of this section of the world if ICTs are made affordable, and the issue of poverty is adequately addressed. Among the several road bumps against ICT diffusion in LDCs that the paper identified are illiteracy, poverty, poor ICT infrastructure, and weak policy and regulatory framework. It is the paper’s position that these obstacles, no matter how daunting they look, are surmountable given the right government policy and collaboration among the government, the private sector and civil society. The work offered elaborate measures of how to dismantle the road blocks against ICTs’ penetration in LDCs. Key words: Impediments, Information, Communication, Technology, Least Developed   Countrie

    Nigerian Newspaper Coverage of Militancy in the Niger Delta

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    The study analyzed Nigerian newspaper coverage of militancy in the Niger Delta region of Nigeria. Content analysis was used to generate data for the study. Four purposively selected Nigerian national dailies: THISDAY, The Guardian, Vanguard, and The Sun published between January 1, 2006 and October 4, 2009 were content analyzed. The population was 5,532 issues from where a sample of 553 was systematically selected. The units of analysis for the study include straight news, feature article, editorial opinion, interview, and letter to the editor that made reference to militancy in the Niger Delta. Coding was by two independent coders based on frequency, prominence, portrayal of militancy, format of presentation, and language of reports. The results showed that Nigerian Newspapers covered militancy in the Niger Delta in a fair, balanced and responsible manner, even though there were a few instances when confrontational languages slipped into reports. It also found that the dailies accorded low prominence to reports on militancy in the Niger Delta and did not endorse militancy as the preferred option for resolving the conflict in the region. Rather, they advocated a peaceful resolution of the conflict as is evident in the high score (77.88%) of the use of conciliatory tone in their reports. On the downside, the preponderance of straight news indicated that not much of conflict analysis and interpretative reporting was done in the coverage to help readers grasp thoroughly the dominant issues involved in militancy. The conclusion is that by presenting a balanced coverage, the dailies have helped in setting the right agenda and mediating in the conflict. This may have contributed in some degree to the management of the problem of militancy in this region. Accordingly, it is recommended, among others, that reporters and editors should include more of feature articles, editorials, and interviews with conflict experts, victims, and local residents in their coverage. This will help create proper understanding of the issues at stake in order to facilitate early conflict resolution

    Awareness, benefits and drawbacks of net zero energy building practices: construction industry professional’s perceptions

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    In a bid to overcome climate change and global warming, the adoption of net zero energy building (nZEB) practices in construction projects has become a viable measure of reducing energy consumption and CO2 emissions in buildings. nZEB is a facility with a significantly lowered energy needs such that the rest of the energy requirements can be supplied by on-site or off-site renewable technologies. The present study therefore investigated the awareness, benefits and challenges confronting the actualization of nZEB in Nigeria construction industry. A cross sectional survey design was adopted wherein a close ended questionnaire was purposively administered online to construction industry professionals who have understanding of nZEB initiatives. Descriptive statistical tests were conducted, with the results showing about 9% and 25% of the selected professionals been not aware of nZEB concepts and have not been involved in the concept in their professional career. Further details revealed that reduction in the land use effect, reduction in vulnerability of power infrastructures to vandalism and economic competitiveness were dominant benefits of nZEB practices. However, low return on investment, conflict with public policy regulation and policy clarity, lack of evaluation and valuation processes were perceived as the top hindering factors to nZEB practices. The implication for practice is for construction stakeholders to participate and develop effective implementation strategies towards nZEB for could be ecological and economical friendly

    Influence of bamboo fiber and limestone powder on the properties of self-compacting concrete

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    This paper examines the effect of combined bamboo fibers and limestone powder used as filler material on the fresh, hardened and microstructural properties of self-compacting concrete (SCC). The bamboo fibers of aspect ratio (l/d) of 50 and a maximum length of 50 mm was varied in steps of 0.25%, 0.5%, 0.75% and 1% in the SCC mix. While 10% of limestone powder was added as a filler in each of the SCC mix. The workability of the mix was assessed by slump flow test and V-funnel test, while the mechanical properties were assessed by considering the compressive and split tensile strength test after 7, 14 and 28 curing age. All concrete mixes were carried out by following the European Federation for Specialist Construction Chemicals and Concrete (EFNARC) standard, while the microstructure of selected samples was assessed using the Scanning Electron Microscopy (SEM). Test results indicate that fiber addition influences the fresh properties of SCC. Moreover, it was observed that SCC mix containing with fiber content of 0.75% and 0.5% with the inclusion of 10% limestone powder achieved the highest compressive and split tensile strength values of 28.04 MPa and 3.26 MPa, respectively. The result showe

    Obstetric analgesia for vaginal birth in contemporary obstetrics: a survey of the practice of obstetricians in Nigeria

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    BACKGROUND: Contemporary obstetrics in sub-Saharan Africa is yet to meet the analgesic needs of most women during child birth for a satisfactory birth experience and expectedly, obstetricians have a major role to play in achieving this. METHODS: This was a questionnaire-based, cross-sectional study of 151 obstetricians and gynecologists that attended the 46th Annual General Meeting and Scientific Conference of the Society of Gynaecology and Obstetrics of Nigeria (SOGON) held in Abakaliki, southeast Nigeria in November, 2012. SOGON is the umbrella body that oversees the obstetric and gynecological practice in Nigeria. Data was collated and analyzed with Epi-info statistical software, and conclusions were drawn by means of simple percentages and inferential statistics using Odds Ratio, with P-value < 0.05 at 95% Confidence Interval (CI) taken to be statistically significant. RESULTS: Of the 151 participants, males predominated; 110 (72.9%) practiced in government-owned tertiary hospitals in urban locations. Only 74 (49%) offered obstetric analgesia. Among users, only 20 (13.3%) offered obstetric analgesia routinely to parturients, 44 (29.1%) sometimes and 10 (6.6%) on patients’ requests. The commonest analgesia was opioids (41.1%). Among non-users, the commonest reasons adduced were fear of respiratory distress (31.1%), cost (24.7%) and late presentation in labour (15.6%). CONCLUSION: The routine prescription and utilization of obstetric analgesia by obstetricians in Nigeria is still low. Obstetricians are encouraged to step up its use to make childbirth a more fulfilling experience for parturients

    Investigating for Pozzolanic Activity in Palm Kernel Nut Waste Ash (PKNWA) with Cement towards a Sustainable Construction

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    The earth is not inherited from our ancestors but borrowed from our children and should be returned the way we met it and even better. This is the essence of sustainability, preserving the earth. One of the main consequence of a non-sustainable world is global warming caused by the release of greenhouse gasses into the atmosphere that deplete the earth’s protective layer from extreme sun radiation. This results in global temperature rise leading to tsunamis and other “natural disasters” making us more vulnerable to extreme weather elements. Urbanization and industrialization bring about high construction rate to accommodate them resulting to global demand for concrete production. Concrete production contributes about 5% of the world’s carbon dioxide (CO2) emission and bulk of these emissions are in cement production. Cement is not an eco-friendly material and the sharp decrease in its use is highly needed to improve sustainable construction. Another issue discouraging its use is the rising cost, making housing unaffordable even to the middle class. This have resulted in finding series of housing financing systems to cope with rising cost of housing. One of the ways of achieving this is by the use of pozzolanic and blended cements to reduce the quantity of cements needed to meet the global concrete demand. This study examines the Pozzolanic Potentials of Palm Kernel Nut Waste Ash (PKNWA) as a blend with cement in Nigeria. Nigeria is currently the third world leading producer of palm which bears the nut and also accounts for over half of the palm produced in Africa. Palm kernel nut becomes an agro-waste when the oil is extracted. This study shows that PKNWA can comfortably replace cement by 10% and even produce a more durable binder than when cement is wholly used. The utilization of PKNWA in blended cement production will reduce the need for cement and prevent the ecological hazard resulting from the disposal of the waste palm nuts

    Modified mix design development specification batched by volume from specified mix design by weight towards improved concrete production

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    Concrete production process is usually designed to meet certain fresh properties, target strength and durability requirement. This process is referred to as the mix design, which guides the quantity and proportions of the various constituent materials to produce the concrete. Concrete mix designs are usually done in accordance to specified standard procedures in codes developed by recognized institutions like the Building Research Establishments (BRE) [ 1 ]. Other acceptable mix design methods includes the three (3) equation and double coating methods in [ 2,3 ]. Standardized prescribed mix designs are generally accepted designs that meet strength requirements in normal strength concrete class as specified in [ 4,5 ]. Standardized Prescribed Concrete mixes have been designed and the characteristic strengths specified in the British standards [ 4,5 ] and the specified concrete mix design is recommended to be batched by weight. •Predominantly, mix designs are batched by volume within the study area and most developing countries which results to the production of less durable concrete than when batched by weight. This practice is due to the higher cost of acquiring the batching plants [ 6 ] employed in concrete production by medium to small scale construction firms. •This study developed a method of deriving a mix design to be batched by volume from the specified mix designed by weight using a design chat developed from [ 4,5 ]. Concrete can then be produced with the derived mixed design and batched by volume as though it was batched by weight from the specified mix design. This method eliminates the strength disparity by both batching methods and production of more durable concrete in most developing countries

    Mechanical properties of high strength eco-concrete containing crushed waste clay brick aggregates as replacement for sand

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    Utilization of clay brick wastes for production of high strength eco-concrete enables the combat of raw resources depletion due to excessive mining as well as mitigating environmental pollution caused by demolition of old brick structures in an effort to achieve environmental sustainability in line with the sustainable development goals (SDGs). This study investigates the beneficial usage of crushed clay brick as partial replacement for natural sand in producing high strength eco-friendly concrete. The replacement percentages of the crushed clay brick in respect to sand are 0, 10, 20, 30, 40 and 50% by weight using a mix proportion ratio of 1:1:2 at a constant water-cement ratio of 0.25, aiming at the 28 days compressive strength of about 40 MPa. The chemical characterization of the crushed clay brick and cement was conducted via X-ray fluorescence (XRF). The mechanical properties tests were performed on about 80 specimens using 100 x 100 x 100 mm for cubes, 100 x 100 x 500 mm for beams and 100 x 200 mm diameter for cylinders after 7, 14 and 28 days of curing in water. Results showed that concrete containing crushed clay brick as partial replacement for sand compare favourably well with the control. Consequently, it is suggested that generated clay brick wastes can be crushed and used as replacement for natural sand for the production of eco-friendly high strength concrete

    Influence of Dicalcium Silicate and Tricalcium Aluminate Compounds in Different Local Cement Brands on the Compressive Strength of Normal Concrete

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    The mould-ability of concrete into intricate forms and the versatility of its constituent materials has made concrete to be the most preferred construction material. However, in developing nations such as Nigeria, poor quality of concrete is listed among the common causes of building collapse. Thus, this study investigated the effects of chemical compounds of four commonly used local ordinary Portland cement brands on the compressive strength of normal concrete. The cement was labelled brands A, B, C, and D, respectively, while all the other constituent materials remained constant in this study. The HACH DR 200 direct reading spectrophotometer method was used to analyze the composition of the oxide in each of the cement samples, while the Bogue composition formula was used to estimate the compound compositions of the cement samples. A designed mix proportion of 1:2:4 (cement: sand: granite) at water-cement ratio (w/c) of 0.6 was used to produce the concrete with an expected target strength of 25 N/mm2. Also, the initial and final setting time of the cement samples and the workability of the concrete mixes were determined. Forty-Eight (48) numbers cube samples were cast and tested for compressive strength at 3, 7, 14, and 28 curing days,respectively, using a 150 mm concrete cubes. The result shows the setting time of the cement samples to be within an acceptable period. Also, results indicated that the cement brands have a significant percentage of Tricalcium Silicate (C3S) content and low percentage Dicalcium Silicate (C2S) content responsible for faster hydration rate and higher early strength gain of the concrete. However, it was observed that a higher percentage of Tricalcium aluminate (C3A) leads to higher strength gain from 7 to 28 days of curing age

    Ring-opening polymerization of rac-lactide mediated by tetrametallic lithium and sodium diamino-bis(phenolate) complexes

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    Lithium and sodium compounds supported by tetradentate amino-bis(phenolato) ligands, [Li2(N2O2BuBuPip)] (1), [Na2(N2O2BuBuPip)] (2) (where [N2O2BuBuPip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4,6-tert-butylphenol), and [Li2(N2O2BuMePip)] (3), [Na2(N2O2BuMePip)] (4) (where [N2O2BuMePip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4-methyl-6-tert-butylphenol) were synthesized and characterized by NMR spectroscopy and MALDI-TOF mass spectrometry. Variable temperature NMR experiments were performed to understand solution-phase dynamics. The solid-state structures of 1 and 4 were determined by X-ray diffraction and reveal tetrametallic species. PGSE NMR spectroscopic data suggests that 1 maintains its aggregated structure in CD2Cl2. The complexes exhibit good activity for controlled ring-opening polymerization of rac-lactide (LA) both solvent free and in solution to yield PLA with low dispersities. Stoichiometric reactions suggest that the formation of PLA may proceed by the typical coordination–insertion mechanism. For example, 7Li NMR experiments show growth of a new resonance when 1 is mixed with 1 equiv. LA and 1H NMR data suggests formation of a Li-alkoxide species upon reaction of 1 with BnOH
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