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Risk Assessment of Human Exposure to 2-Methylnaphthalene, Phenanthrene and Didodecylphthalate via Consumption of Shrimps (Macrobrachium vollenhovenii) from Qua Iboe River Estuary, South-South Nigeria
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作者 Inyang O. Oyo-Ita Bassey B. Asuquo +1 位作者 Emmanuella E. Oyo-Ita Orok E. Oyo-Ita 《Journal of Geoscience and Environment Protection》 2023年第6期125-144,共20页
Ibeno, one of the major oil producing communities in South-South Nigeria is a coastal commercial fishery hub that houses Axon-Mobil operational base and pharmaceutical/plastic industries. Shrimp species (Macrobrachium... Ibeno, one of the major oil producing communities in South-South Nigeria is a coastal commercial fishery hub that houses Axon-Mobil operational base and pharmaceutical/plastic industries. Shrimp species (Macrobrachium vollenhovenii) is a major aquatic food frequently consumed by inhabitants of the coastal area and those living hinterland, thus, being a major route of human exposure to 2-methylnaphthalene, phenanthrene and didodecyl phthalate in the area. The purpose of the study was to evaluate factors that determine bioaccumulation and assess the potential cancer and non-cancer risk posed by these contaminants through human (adult and children) exposure via shrimp’s consumption using gas chromatography-mass spectroscopy. The associated sediment showed higher mean concentrations of 2-methylnaphthalene, phenanthrene and didodecylphthalate at the two sites relative to those in fresh shrimp samples and factors such as size, lipid content, physicochemical property and environmental condition influenced the uptake of these contaminants. Besides water loss, the traditional drying process enhanced the levels of phenanthrene and didodecylphthalate in dry shrimps most likely due to combustion process and relatively low volatility, respectively and lowered the level of 2-methylnapthalene linked to its relatively high volatility. The potential of cancer and non-cancer development in human were highest via dry large shrimp consumption and followed the sequence: dry small shrimp > fresh large shrimp > fresh small shrimp and were within the USEPA reference standards. Although children were more vulnerable, the exposed individuals may not exhibit notable health-associated adverse effects in the near future. Thus, adequate advocacy is needed to sensitize those living in the catchments who often prefer dry shrimp in their meals on the adverse health implications of these contaminants for their survival and the need to maintain the health of the ecosystem. 展开更多
关键词 BIOACCUMULATION Human Exposure Toxicity Potential SHRIMP
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The Impact of Encroachment on the Distribution of Tree Species in Cross River National Park, Oban Division, Nigeria
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作者 Margaret A. Yaro 《Journal of Environmental Protection》 2015年第7期744-754,共11页
Increasing human activities around protected area pinpoint to looming degradation and alteration of the component of such areas, especially where adequate measures are not taken to forestall encroachment. The Oban div... Increasing human activities around protected area pinpoint to looming degradation and alteration of the component of such areas, especially where adequate measures are not taken to forestall encroachment. The Oban division of the Cross River National Park is one of the oldest rainforests and has been identified as a biodiversity hotspot. However, communities settling around the park have been involved in some economic activities for their livelihood. Resource utilization at the edge of the park may alter the components of the park such as species diversity. Therefore this study is geared towards assessing the impact of human encroachment and the concomitant impact on the distribution of species within the park. The study adopted participatory research methods which included Focus Group Discussion and participatory mapping as well as a plot based survey which involved the laying of sample plots within two zones of the park designated as areas bounded by cultivated land and areas bounded by fallow. Three 40 m × 40 m square plots are laid along a 320 meter transect measured from the boundary of the park at each buffer zone. The plots are separated by 100 m gap. From the result obtained, it is discovered that Musanga cercropoides dominates the outer plots of the cultivated zones and fallow zones comprising 20.2 and 21.5 percent respectively while Terminalia ivorensis dominates the middle and inner areas of the park. Moreover the composition of species decreases inward to the inner part of the park. Diversity index decreases in the order of 2.566 < 2.348 < 2.163 at the cultivated zones and 2.443 < 2.376 < 2.366 at the fallow zones. It is concluded that human activities close to the park alters the species composition of the park. Hence, it’s recommended that adequate alternatives livelihood and incentive be provided to support zone communities to reduce their dependents on the edge of the park. 展开更多
关键词 PARK ENCROACHMENT Impact Diversity Colonizers ZONES
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The assessment of heavy metal pollution in river sands of Jalingo,Nigeria using magnetic proxy parameters,pollution,and ecotoxicological indices
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作者 Maxwell O.Kanu Augustine A.Abong 《Acta Geochimica》 EI CAS CSCD 2022年第6期1083-1103,共21页
The measurement of environmental magnetic properties and metal contents of sands from Nukkai(NKR),Mayo-Gwoi(RMYG)and Lamurde(LR)rivers located in Jalingo,Nigeria are reported.We seek to determine the extent of anthrop... The measurement of environmental magnetic properties and metal contents of sands from Nukkai(NKR),Mayo-Gwoi(RMYG)and Lamurde(LR)rivers located in Jalingo,Nigeria are reported.We seek to determine the extent of anthropogenic impact on the river sands using magnetic-proxy-parameters,pollution and ecotoxicological indices and multivariate statistics.Measurements of magnetic susceptibilityχ,frequency-dependentsusceptibilityχfd%,anhystericremanent magnetization,isothernal remanent magnetization and X-ray fluorescence were undertaken.The average values of theχ(in×10^(-8)m^(3)kg^(-1))were 24.53,12.76 and 39.27 for NKR,RMYG and LR sites respectively,implying that the magnetic minerals in the sands were mostly ferrimagnetic.The meanχfd%value of 2.64%,4.85%and 3.53%for NKR,RMYG and LR respectively suggest that the study area was dominated by multi-domain magnetic grain sizes.The value of the S-ratio is~1 in all river samples,suggesting that low coercivity magnetic minerals(e.g.,magnetite)dominated the samples.The mean concentrations of Ti,Zr,Sn,Ba and Pb were higher than the background values in the studied samples.All the estimated pollution indices puts the level of pollution of the river sands between low and moderate pollution with Sn,Ba and Pb as the elements of concern.Multiple sources of metal contents such as fertilizers,pesticides,waste dumps and vehicular sources etc.were found.Significant positive correlations between magnetic parameters(particularly,SIRM)and some heavy metals and pollution/ecotoxicological indices were obtained,showing that magnetic methods could be used as a geochemical proxy for pollution assessment. 展开更多
关键词 Magnetic susceptibility Ecotoxicological risk index Pollution index Heavy metals pollution RIVER
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The biomedical significance of the phytochemical, proximate and mineral compositions of the leaf, stem bark and root of Jatropha curcas 被引量:2
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作者 Atamgba Agbor Asuk Margaret Akpana Agiang +1 位作者 Kayode Dasofunjo Amonor James Willie 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2015年第8期635-641,共7页
Objective: To analyse the phytochemical contents of leaf, stem bark and root of Jatropha curcas(J. curcas) in four solvent extracts and their proximate and mineral compositions. Methods: Standard analytical procedures... Objective: To analyse the phytochemical contents of leaf, stem bark and root of Jatropha curcas(J. curcas) in four solvent extracts and their proximate and mineral compositions. Methods: Standard analytical procedures were used for the determination of phytochemicals, proximate and mineral compositions of the leaf, stem bark and root extracts of J. curcas. Results: Results of the analysis showed the presence of polyphenols, flavonoids, alkaloids, cardiac glycosides, coumarins, saponins, terpenoids, steroids, triterpenoid saponins, carotenoids, phlobatannins and tannins in the leaf, stem bark and root of all the solvent extracts. Flavonoids were present in the highest amount in the ethyl acetate extracts of the leaf(7.35% ± 0.02%), stem bark(4.12% ± 0.01%) and root(3.35% ± 0.02%) followed by polyphenols in the methanol extracts of leaf(4.62% ± 0.02%), stem bark(2.77% ± 0.05%) and root(2.49% ± 0.02%). Poly-acetylated compounds were absent in all the solvent extracts of the leaf, stem bark and root. However, some anti-nutritional agents such as oxalates, phytates and cyanates were present in all the solvent extracts of the leaf, stem bark and root except the ethyl acetate. Phytates were high in the aqueous solvent of the leaf(6.12% ± 0.00%) but low in the stem bark(1.00% ± 0.05%) and root(0.89% ± 0.03%). Proximate composition showed appreciable amounts of total carbohydrate(36.33% ± 0.72%), crude protein(26.00% ± 0.47%) and reducing sugars(5.87% ± 0.14%) in the leaf, while crude fat was more in the stem bark(16.70% ± 0.30%). There was corresponding substantial energy in the leaf [(1 514.77 ± 20.87) kJ /100 g] and stem bark [(907.00 ± 8.52) kJ /100 g]. Moisture and ash contents of the leaf, stem bark and root were within acceptable limits for the use in drugs formulation. The mineral composition showed substantial amounts of important elements such as Fe, Ca, Na, Mg and Zn. Others were P, K and Se. Conclusions: The outcome of this study suggests that the leaf, stem bark and root of J. curcas have very good medicinal potentials, meet the standard requirements for drug formulation and serve as good sources of energy and nutrients except for the presence of some anti-nutritional elements predominant in the leaf. 展开更多
关键词 JATROPHA curcas Solvent extracts PHYTOCHEMICALS PROXIMATE COMPOSITION Mineral COMPOSITION
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Anti-Lipidemic Effect of Combined Leaf Extracts of <i>Moringa oleifera</i>and <i>Peristrophe bicalyculata</i>in Alloxan-Induced Diabetic Rats 被引量:2
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作者 I. A. Iwara G. O. Igile +4 位作者 I. P. Ogar O. E. Mboso U. P. Ujong E. U. Eyong P. E. Ebong 《Pharmacology & Pharmacy》 2014年第4期340-348,共9页
In this study, the anti-lipidemic effects of combined extracts of Moringa oleifera and Peristrophe bicalyculata in allxoan-induced diabetic rats were investigated. Fifty four (54) adult male albino Wistar rats weighin... In this study, the anti-lipidemic effects of combined extracts of Moringa oleifera and Peristrophe bicalyculata in allxoan-induced diabetic rats were investigated. Fifty four (54) adult male albino Wistar rats weighing between 140-180 g were shared into 5 parallel groups consisting of diabetic (DC) and non-diabetic (NC) groups. Each group consisted of 6 rats. Groups 2-5 were made diabetic using alloxan (150 mg/kg b.w in distil H2O). Except for groups 1 and 2, animals were gavaged at doses of 500 mg/kg b.w for the single dose of extract and 250 mg/kg for the combine extract treatment. Insulin served as a standard drug and was administered at 5IU/kg b.w. The control animal groups (NC, DC) received 0.2 ml of normal saline (placebo) for fourteen (14) consecutive days. Groups treated with extracts showed a significant (p < 0.05) increase in triglyceride (TG), total cholesterol (TC) levels, very low density lipoprotein (VLDL) and low density lipoprotein (LDL mg/dl) concentrations in all treated groups compared to the diabetic control group. No significant (p > 0.05) change was observed in HDL-C level in treated groups when compared to the normal control, diabetic control and insulin groups, suggesting a potential protection against cardiovascular diseases (CVDs) by these plants. No reduction in body weight was observed within the experimental period of 14 days. The results obtained in this study are in agreement with several other research results with these plants and claims by ethno-medical practitioners on the use of Moringa oleifera and Peristrophe bicalyculata in the treatment of hypertension and related CVDs. 展开更多
关键词 Diabetes Anti-Lipidemia CHOLESTEROL Moringa oleifera Peristrophe bicalyculata HYPERTENSION
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Fishery and the Tourism Potential of Agbokum Waterfalls, Nigeria
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作者 Gabriel Ujong Ikpi Benedict Obeten Offem 《Journal of Water Resource and Protection》 2012年第9期733-745,共13页
Species richness and human activities in natural environments are among the most important recreational needs. Monthly studies of aquatic fauna, artisanal fisheries and tourism characteristics was conducted during wet... Species richness and human activities in natural environments are among the most important recreational needs. Monthly studies of aquatic fauna, artisanal fisheries and tourism characteristics was conducted during wet and dry seasons, over a two year period in the three landscapes along the 6817.7 m length of Agbokum waterfalls by using a close-ended pre-coded survey instrument. Through MANOVA analysis of the 1780 respondents we found strong positive association between peoples visits to the recreational areas and the type of landscape in which the respondents felt happy. People who felt happier in landscape dominated by waterfalls, visit the middle reaches of the river for outdoor recreation more often while people who feel happy in landscapes dominated by slow water current with an extensive wide area and floodplains, visit downstream reaches of the waterfalls more often. Activities performed more often along downstream reaches include fishing, bathing/swimming, boating and hunting while more frequent activities in the middle reaches (waterfalls) include taking photographs, picnics, enjoying nature, outing with family and friends, looking at view, resting and relaxing. A total of 5484 fish representing 22 species belonging to 16 genera from 9 families were sampled with 10 species being restricted to wet season and only 1 in the dry. The number of taxa and individuals present at upstream, midstream and downstream reaches were 16 (2003), 13 (1034), 17 (2447), respectively. Tilapia zillii, Clarias gariepinus and Labeo coubie dominated overall catch constituting 35.5%. Twenty five operational boats counted during the period of study, were only used downstream by 25 full-time fishermen, 87 part-time, 44 shoreline fishermen and 36 assistant fishermen. Common gears were the hook and line constituting 45.8%, cast and dip net (10.1%) bailing (8.7%), gill nets (7.3%), seine net (6.4%) Traps (5.5%), lift net (4.7%) Dip nets (0.9%), poisoning (2.8%), cutlass (3.3%) and spear (1%). Seasonally occurring aquatic fauna include crustaceans (Atya gaboneensis and Palaemon paucidens) (23.5%) oysters (Etheria elliptica) (15.4%), clams (Galacea paradoxa) (20.8%), Manatee (Trichechus senegalensis) (2.5), Hippopotamus amphibious (1.8%), Otter (Lutra macullicolis) (0.5%), Crocodyles (Crocodylus niloticus, Crocodylus cataphractus (Aligata) and Osteolaemus tetraspsis) (18.8%). The nile monitor (Varanus nilaticus), aquatic snake (Anoscopus sp), and three species of water turtle (Kimxys erosa, Pelumedusa sp and Peliosus sp) (21.6%). Relatively higher faunal densities and species richness in the upstream and downstream reaches coupled with waterfalls in middle reaches can makes Agbokum waterfalls a tourism destination if only management strategies include Legislation to conserve these natural resources. 展开更多
关键词 Agbokum Waterfalls FISHING ACTIVITIES Fish Species RECREATIONAL ACTIVITIES Landscapes AQUATIC FAUNA Gears
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Five Steps Block Predictor-Block Corrector Method for the Solution of <i>y''</i>= <i>f</i>(<i>x</i>,<i>y</i>,<i>y'</i>)
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作者 Mathew Remilekun Odekunle Michael Otokpa Egwurube +1 位作者 Adetola Olaide Adesanya Mfon Okon Udo 《Applied Mathematics》 2014年第8期1252-1266,共15页
Theory has it that increasing the step length improves the accuracy of a method. In order to affirm this we increased the step length of the concept in [1] by one to get k = 5. The technique of collocation and interpo... Theory has it that increasing the step length improves the accuracy of a method. In order to affirm this we increased the step length of the concept in [1] by one to get k = 5. The technique of collocation and interpolation of the power series approximate solution at some selected grid points is considered so as to generate continuous linear multistep methods with constant step sizes. Two, three and four interpolation points are considered to generate the continuous predictor-corrector methods which are implemented in block method respectively. The proposed methods when tested on some numerical examples performed more efficiently than those of [1]. Interestingly the concept of self starting [2] and that of constant order are reaffirmed in our new methods. 展开更多
关键词 Step Length Power Series BLOCK PREDICTOR BLOCK CORRECTOR Constant Order Step Size Grid Points Self Starting Efficiency
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Impact of Element Spacing on the Radiation Pattern of Planar Array of Monopole Antenna
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作者 Ofem U. Omini Donatus E. Baasey Sulaiman A. Adekola 《Journal of Computer and Communications》 2019年第10期36-51,共16页
In recent years, several attempts have been made in designing planar array antennas with high directivity. This paper is aimed at investigating the impact of element spacing on the directivity of planar array of monop... In recent years, several attempts have been made in designing planar array antennas with high directivity. This paper is aimed at investigating the impact of element spacing on the directivity of planar array of monopole antenna. The directivity of antenna with reduced grating lobes can be obtained by carefully varying the inter-element spacing of array antenna. Based on this conception, this paper presents the investigation carried out on the relationship between inter-element spacing and the directivity of planar array of monopole antenna. It went further to highlight the effect on the total fields radiated by the antenna. The inter-element spacing is one of the most important antenna parameters that determine the directivity of the antenna. For a planar array of monopole, the directivity can be improved by varying the inter-element spacing. Four elements uniform planar array antenna and Hadamard matrix method was used to determine element positioning in the array matrix. The simulated results obtained using Matlab, showed that good directivity was obtained by using element spacing between 0.1λ - 0.5λ. Increasing the spacing beyond 0.6λ - 1.0λ also improved the directivity, but generated many grating lobes. As inter-element spacing increased, the grating lobes increased in size, number and levels. The study, therefore, inferred that the best directivity (radiation pattern) can only be obtained when the element spacing is within 0.1 - 0.5λ. 展开更多
关键词 GRATING LOBES ARRAY Antenna PLANAR ARRAY ARRAY Factor DIRECTIVITY Element SPACING
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Lead-Induced Damage on Hepatocytes and Hepatic Reticular Fibres in Rats;Protective Role of Aqueous Extract of <i>Moringa oleifera</i>Leaves (Lam)
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作者 Bukola R. Omotoso Adeleke A. Abiodun +1 位作者 Omamuyovwi M. Ijomone Stephen O. Adewole 《Journal of Biosciences and Medicines》 2015年第5期27-35,共9页
This study was designed to evaluate the hepatoprotective and ameliorative effects of aqueous extract of Moringa oleifera (MO) leaves on the histologyof liver and hepatic reticular fibres integrity of adult Wistar rats... This study was designed to evaluate the hepatoprotective and ameliorative effects of aqueous extract of Moringa oleifera (MO) leaves on the histologyof liver and hepatic reticular fibres integrity of adult Wistar rats following lead-induced hepatotoxicity. Twenty four adult Wistar rats, weighing 180 - 220 g, randomly assigned into four groups of six animals each were used for the study. Lead and Moringa oleifera were given orally to the rats. 24 hours after the last administration, animals were sacrificed, blood obtained by cardiac puncture and liver excised, fixed in 10% phosphate buffered formalin for histological and histochemical analysis. The activities of aspartate amino transferase (AST), alanine amino transferase (ALT) and alkaline phosphatase (ALP) were used as markers of hepatotoxicity and catalase (CAT) activity were used as marker to evaluate the anti-oxidant status of the tissue. Result showed that lead treatment increased markers of hepatic damage (ALT, AST and ALP) and decreased CAT activities. Histological studies reveal alterations of hepatic structure including hepatocytic vacuolations, sinuosoidal congestion and loss of reticular fibres following lead treatment. Treatment with MO prevented and reversed lead induced hepatic damage. In conclusion, this study shows that Moringa oleifera leaf extract has an appreciable ability to prevent hepatotoxicity caused by lead, partly as result of its chemical constituents which has hepatoprotective properties. 展开更多
关键词 LEAD Moringa oleifera Liver RETICULAR Fibres RATS
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Evaluation of the Effect of Gurusa, a Ugandan Cereal-Based Fermented Food on Serum Lipid Profile and Body Weight of Wistar Albino Rats
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作者 Atamgba Agbor Asuk Abbas Kisambira +1 位作者 Muhammad Lubowa Denis Ssenabulya 《Food and Nutrition Sciences》 2016年第4期284-293,共10页
The effect of Gurusa, a fermented traditional food on lipid profile and body weight was investigated. Thirty male albino rats weighing between 75 - 115 g assigned into five study groups designated A to E (n = 6) were ... The effect of Gurusa, a fermented traditional food on lipid profile and body weight was investigated. Thirty male albino rats weighing between 75 - 115 g assigned into five study groups designated A to E (n = 6) were fed 20 g of prepared pellets and tap water given ad libitum. The animals were served graded doses of Gurusa. Group A was served 100% rat chow pellets (made of maize bran);groups B, C and D were given pellets of 75% rat chow and 25% Gurusa, 50% rat chow and 50% Gurusa, 25% rat chow and 75% Gurusa respectively while group E was served 100% Gurusa. The lipid profile showed a dose dependent effect of Gurusa administration as one moves down the groups. Group D had a reverse action of group B and showed significant (P < 0.05) increase in TC, TG and HDL compared to groups A and B but a significant (P < 0.05) decrease in LDL compared to group B. Weight changes in group B produced a significant (P < 0.05) increase in MWI and GR compared to the other groups. There was no significant (P ≥ 0.05) difference in MWI and GR of group D when compared with group A. However group C showed significant (P < 0.05) increase in MWI and GR when compared with group A. Gurusa consumption alters both lipid profile and body weight and its combination with maize bran or other foods rich in dietary fibre, have potential to serve therapeutic purposes in the prevention of atherosclerosis and obesity depending on the intended objective. 展开更多
关键词 Traditional Diet ATHEROSCLEROSIS OBESITY Proximate Composition Nubians
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A New Block-Predictor Corrector Algorithm for the Solution of y’’’=f(x, y, y’, y’’)
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作者 Adetola O. Adesanya Mfon O. Udo Adam M. Alkali 《American Journal of Computational Mathematics》 2012年第4期341-344,共4页
We consider direct solution to third order ordinary differential equations in this paper. Method of collection and interpolation of the power series approximant of single variable is considered to derive a linear mult... We consider direct solution to third order ordinary differential equations in this paper. Method of collection and interpolation of the power series approximant of single variable is considered to derive a linear multistep method (LMM) with continuous coefficient. Block method was later adopted to generate the independent solution at selected grid points. The properties of the block viz: order, zero stability and stability region are investigated. Our method was tested on third order ordinary differential equation and found to give better result when compared with existing methods. 展开更多
关键词 COLLECTION INTERPOLATION Power Series APPROXIMANT Linear MULTISTEP Continuous COEFFICIENT Block Method
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Selection of Maize Genotypes Resistant to Pink Stem Borer and Sugarcane Borer
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作者 Abraham Agwu Ngwuta Samson Oyewole Ajala +1 位作者 Ignatius Ugwudlke Obi Ene-Obong Efiom Ene-Obong 《Journal of Agricultural Science and Technology(A)》 2015年第3期174-182,共9页
关键词 基因型差异 甘蔗螟虫 玉米种质 大螟 尼日利亚 农艺性状 农业研究所 经济作物
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Toyota’s Slow Response to Manufacturing Defects Leading to Recalls: Result of Poor Communication Strategy
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作者 Oyinkepreye L. Bebeteidoh Stephen A. Takim 《Journal of Transportation Technologies》 2016年第5期420-435,共16页
The recall of vehicles in the automobile industry is not limited to any particular company. Recalls most often have been attributed to defective parts supplied by tier one and tier two suppliers. Toyota, a world leade... The recall of vehicles in the automobile industry is not limited to any particular company. Recalls most often have been attributed to defective parts supplied by tier one and tier two suppliers. Toyota, a world leader in the manufacture of automobiles, built on world class corporate brand and Principles known as the Toyota Way, and located in about 53 countries in the world, with most of its production taking place in the North America and Japan. Its Communication strategy leading to recalls has brought it into conflict with its customers and regulatory agencies. Toyota’s seeming departure from its core principles in the Toyota Way has also brought it into conflict with suppliers and affected its production. Answers will be sought for the following research questions: 1) Why with its Toyota Way, Communication became a challenge for Toyota? 2) What is the role of the Media, in Toyota’s issues of recall? A detailed literature survey was conducted for Toyota’s communication strategy. A dialectic inquiry was used to analyse the acquired data, from interviews conducted. 展开更多
关键词 Communication DEFECTS MANUFACTURING Media Strategy Toyota Way
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Effects of Incorporating Expanded Polystyrene in Concrete Construction
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作者 Stanley Emmanuel Ubi D. E. Ewa +1 位作者 Agbor Reagan Bessong Efiok D. Nyah 《Journal of Building Construction and Planning Research》 2022年第3期79-101,共23页
Polystyrene is a highly popular plastic packaging material. It is essentially non-biodegradable and takes hundreds of years to decompose in case of land filling while other disposal methods or treatments methods creat... Polystyrene is a highly popular plastic packaging material. It is essentially non-biodegradable and takes hundreds of years to decompose in case of land filling while other disposal methods or treatments methods create hazardous effects on the environment. However, this material is known to possess properties such as sound insulation, high thermal conductivity, and lightweight, thereby making it a great additive in concrete. Haven incorporated this material into a concrete matrix;in various percentages which served as partial replacement for coarse aggregates, the concretes’ properties were tested and compared with the properties of the conventional concrete. The experimental data was obtained based on the replacement coarse aggregate by EPS volume ratio of 0%, 4%, 8%, 12% and 16%. The concretes’ properties such as its slump, density, compressive strength, flexural strength and split tensile strength were experimentally determined. These results were then used to determine the influence of polystyrene as partial replacement for coarse aggregate was analyzed and the results compared with that of a concrete mix containing no polystyrene. The results obtained from this analysis indicate that the addition of polystyrene in a concrete mix implies smaller densities as the densities of concrete containing 0%, 4%, 8%, 12% and 16% are 2536, 2443, 2363, 2339 and 2316 Kg/m<sup>3</sup> respectively. It was also observed that the compressive strength of the concrete decreased with an increase in the percentage of polystyrene incorporated. This is clearly shown using in the 28<sup>th</sup> day strength of the concrete samples (21.68, 17.25, 15.87, 14.53 and 13.92 mpa for replacements at 0%, 4%, 8%, 12% and 16% respectively). Similarly, the flexural strength of the concrete decreased with an increase in the percentage of polystyrene incorporated. Whereas, the variations in the split tensile strengths were inconsistent as they were notable increments and decrease in the 28th day strength of the various concrete matrixes. 展开更多
关键词 BATCHING CURING Slump Test Flexural Strength Split Tensile Modulus of Elasticity and Density
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Four Steps Continuous Method for the Solution of <i>y″</i>= <i>f</i>(<i>x, y, y′</i>)
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作者 Adetola Olaide Adesanya Mattew Remilekun Odekunle Mfon Odo Udoh 《American Journal of Computational Mathematics》 2013年第2期169-174,共6页
This paper proposes a continuous block method for the solution of second order ordinary differential equation. Collocation and interpolation of the power series approximate solution are adopted to derive a continuous ... This paper proposes a continuous block method for the solution of second order ordinary differential equation. Collocation and interpolation of the power series approximate solution are adopted to derive a continuous implicit linear multistep method. Continuous block method is used to derive the independent solution which is evaluated at selected grid points to generate the discrete block method. The order, consistency, zero stability and stability region are investigated. The new method was found to compare favourably with the existing methods in term of accuracy. 展开更多
关键词 Predictor CORRECTOR COLLOCATION Interpolation Power Series APPROXIMANT Continuous Block Method
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Comparison of Economic Dispatch, OPF and Security Constrained-OPF in Power System Studies RN
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作者 Etete Obio Siddique Ali +5 位作者 Idowu Oyebanjo Daniel Abara Farouk Suleiman Peter Ohiero Daniel Oku Vincent Ogar 《Journal of Power and Energy Engineering》 2022年第8期54-74,共21页
Electricity network is a very complex entity that comprises several components like generators, transmission lines, loads among others. As technologies continue to evolve, the complexity of the electricity network has... Electricity network is a very complex entity that comprises several components like generators, transmission lines, loads among others. As technologies continue to evolve, the complexity of the electricity network has also increased as more devices are being connected to the network. To understand the physical laws governing the operation of the network, techniques such as optimal power flow (OPF), Economic dispatch (ED) and Security constrained optimal power flow (SCOPF) were developed. These techniques have been used extensively in network operation, planning and so on. However, an in-depth presentation showcasing the merits and demerits of these techniques is still lacking in the literature. Hence, this paper intends to fill this gap. In this paper, Economic dispatch, optimal power flow and security-constrained optimal power flow are applied to a 3-bus test system using a linear programming approach. The results of the ED, OPF and SC-OPF are compared and presented. 展开更多
关键词 Economic Dispatch Linear Programming Network Operation Optimal Power Flow Security Constrained Power Flow
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Exergoeconomic Evaluation and Optimization of Dual Pressure Organic Rankine Cycle (ORC) for Geothermal Heat Source Utilization
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作者 Dodeye Igbong Oku Nyong +2 位作者 James Enyia Benjamin Oluwadare Mafel Obhua 《Journal of Power and Energy Engineering》 2021年第9期19-40,共22页
In the present study, a dual-pressure organic Rankine cycle (DORC) driven by geothermal hot water for electricity production is developed, investigated and optimized from the energy, exergy and exergoeconomic viewpoin... In the present study, a dual-pressure organic Rankine cycle (DORC) driven by geothermal hot water for electricity production is developed, investigated and optimized from the energy, exergy and exergoeconomic viewpoint. A parametric study is conducted to determine the effect of high-stage pressure<span><span><span style="font-family:;" "=""><span></span><span><span> </span>and low-stage pressure</span><span></span><span><span> </span>variation on the system thermodynamic and exergoeconomic performance. The DORC is further optimized to obtain maximum exergy efficiency optimized design (EEOD case) and minimum product cost</span></span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "="">optimized design (PCOD case). The exergy efficiency and unit cost of power produced for the optimization of EEOD case and PCOD case are 33.03% and 3.059 cent/kWh, which are 0.3% and 17.4% improvement over base case, respectively. The PCOD case proved to be the best, with respect to minimum unit cost of power produced and net power output over the base case and EEOD case. 展开更多
关键词 Geothermal Water Dual Pressure Organic Rankine Cycle Exergoeconomic Factor OPTIMIZATION
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Estimation of Stature from Percutaneous Tibia Length of Indigenes of Bekwara Ethnic Group of Cross River State, Nigeria
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作者 Ugochukwu Godfrey Esomonu Lukpata Philip Ugbem Ben‑Abua M Donald 《Journal of Forensic Science and Medicine》 2016年第4期219-221,共3页
Estimating stature by developing linear regression equations which incorporate the features of fragmented body parts or human skeletal remains has been employed by many forensic anthropologists to establish the identi... Estimating stature by developing linear regression equations which incorporate the features of fragmented body parts or human skeletal remains has been employed by many forensic anthropologists to establish the identity of victims of mass disaster although all formulas are ethnic,age,and gender specific.The study is aimed at using the percutaneous tibia length(PCTL)to deriving a specific regression equation formula which could be used to estimate the stature of adult indigenes of Bekwara ethnic group in Cross River State.A total number of 600 subjects within the age range of 21–45 years were recruited randomly for this research(300 males and 300 females).Observed height and PCTL were measured using the standard anthropometric technique,respectively.Stature was estimated from PCTL using simple regression analysis.On analysis of the data,the mean PCTL for male was found to be 43.60±2.31 cm while that of female was 42.55±2.83 cm.The observed height was 165.80±6.88 cm and 156.70±6.06 cm for male and female,respectively.Statistical analysis showed that the male values of the measured parameters were significantly higher than the corresponding female values.The linear regression equations derived for male and female for the estimation of height using the PCTL was found to be 5.289(PCTL)+(−64.78)and 4.230(TL)+(−23.28),respectively.It was concluded that stature can be estimated using the length of an intact mutilated leg.Thus,the data of this study are recommended in anthropological studies for stature estimation among the ethnic group under study. 展开更多
关键词 Bekwara Cross River State percutaneous tibia length stature
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Empirical Studies on Topographical Influences on Crbc/Akbc Terrestrial Television Stations’ Signals in Akpabuyo Local Council Area, Nigeria
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作者 Donatus Enang Bassey Godwin O. Effiong +1 位作者 Ofem U. Omini Effiong O. Obisung 《Journal of Computer and Communications》 2019年第9期50-71,共22页
Dissemination of information to citizens is a relevant component of governance. Expectedly, viewers tuned to broadcast stations within and outside their localities, expecting their receivers to faithfully reproduce th... Dissemination of information to citizens is a relevant component of governance. Expectedly, viewers tuned to broadcast stations within and outside their localities, expecting their receivers to faithfully reproduce the exact features of the transmitted signal. Akpabuyo is a dense forest zone near the creeks leading to the Atlantic ocean in Cross River State, Nigeria. The location has distinct environmental characteristics that made Akpabuyo Area Council, a challenging location to propagate electromagnetic waves;and therefore recipe for further investigation. Radio frequency analyzer, with 24 channels spectrum, ranging between 46 - 870 MHz (model: RO.VE.R.-“DLM3-T”) was deployed to capture signals from terrestrial television stations (TV). CATV measured signal of TV stations in dB, dBμV and dBmV. Its frequency ranged from 40 - 860 MHz;while varying from channel 1 to channel 69. Measurements taken from Akpabuyo L.G.A. showed the following results: the signal strength received from VHF Channel 11 ranged from 20 dBμV to 49 dBμV. From recorded empirical statistics from the study, 50% of the area received signal from this station above 30 dBμV, while other regions had signals below this value;representing the fringe zone of the frequency. The results obtained from the study relatively showed acceptance with Egli’s model. The study recorded a steady fluctuation between 17 dBμV and 19 dBμV from both propagating stations. However, Channel 27 signal at 519 MHz, had very weak signal coverage in Akpabuyo Local Government Area;with signal strength dropped to as low as 13 dB in many parts of the rural area. The study discovered that the state’s broadcasting stations, both at UHF and VHF channels did not transmit successfully across this densely forest (rural) location. Remedial measures such as installing Repeater stations at different locations as signal booster were recommended. 展开更多
关键词 Akamkpa Biase BROADCAST Station Channels Propagation Models Signal TELEVISION STATIONS UHF/VHF SIGNALS
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Hepatitis B Virus (HBV) Serological Patterns in Benue State, Nigeria
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作者 Emmanuel Msugh Mbaawuaga Christian Ukuoma Iroegbu Anthony Chibuogwu Ike 《Open Journal of Medical Microbiology》 2014年第1期1-10,共10页
A total of 1535 randomly collected blood specimens from different groups of consenting subjects in Benue State, were screened by ELISA for Hepatitis B surface antigen (HBsAg), hepatitis B surface antibodies (HBsAb), h... A total of 1535 randomly collected blood specimens from different groups of consenting subjects in Benue State, were screened by ELISA for Hepatitis B surface antigen (HBsAg), hepatitis B surface antibodies (HBsAb), hepatitis B core antibodies (HBcAb), hepatitis Be antigen (HBeAg) and Hepatitis B core IgM antibodies (HBcIgM). The pattern of occurrence of these HBV markers in each blood sample was used to determine individuals with current, acute or chronic infection histories. Of the 1535 sampled individuals, 1319 (85.9%) showed a serological evidence of exposure to HBV infection, some through natural infection (22.7%) and others (13.0%) through vaccination;12% of the exposed were inferred to be currently infected and 91.2% chronically infected. Hepatitis delta virus (HDV) antigen was also detected in 2.7% of the HBsAg positive individuals;and was encountered more (6.7%) in those with acute hepatitis than those with chronic disease. Thus, there are apparently healthy persons with acute and chronic HBV and HDV infection who may serve as source of infection to others. This calls for a government organized Hepatitis Programme to treat cases of acute and chronic hepatitis and roll out strategy for preventing the spread of HBV infections. 展开更多
关键词 HBV MARKERS Acute HBV Chronic HBV HDV Benue STATE
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