227 research outputs found
The zooplankton and environmental characteristics of Yardantsi Reservoir, Gusau, Nigeria
Zooplankton play an important role in the faunal biodiversity of aquatic ecosystems as they assist in transferring algal energy to higher trophic levels through grazing and also eliminate harmful algae from water. The zooplankton and environmental characteristics of Yardantsi Reservoir were studied in order to provide essential information on this important ecosystem that serves as domestic and irrigation water supply, and fishing ground. Samples for water quality and zooplankton analyses were collected from the reservoir from May, 2015 to April, 2017 using standard methods. Three groups of zooplankton (Copepoda, Cladocera and Rotifera) comprising of thirteen genera were encountered. Rotifera (36.69%) and Cladocera (34.44%) were numerically dominant during the rainy and dry seasons, respectively. The highest zooplankton abundance (5646), species richness (11), Shannon-Weiner index (2.25) and Margalef's index (1.16) were observed during the rainy season. Axes 1 and 2 of the principal component analysis (PCA) explained 74.82% and 11.89% of the zooplankton-environmental variable relationship. Diaphanosoma sp, Eubranchipus sp, Kellicottia sp and Macrothrix sp were mostly influenced by NO3, BOD, depth, pH and dissolved oxygen while Cyclops sp and Daphnia were mostly influenced by changes in alkalinity, hardness and chloride. Brachionus patulus, the dominant species in the reservoir was mostly influenced by PO4-P. The study shows that the reservoir is slightly polluted and it is essential to adopt effective management strategies such as reduced agricultural run-offs and riparian animal grazing to prevent further deterioration of water quality
Effect of Science-Technology-Society Approach on Creativity in Environmental Conservation Concept among Secondary School Biology Students in Zaria, Kaduna State
Creativity in STEM Education is now widely recognized as an essential 21st century skill, which can be fostered through innovative pedagogy. This study therefore examines the effect of Science-Technology-Society (STS) Approach on creativity in Environmental Conservation Concept among secondary school biology students in Zaria, Kaduna State. The design is quasi-experimental, specifically the non-equivalent pretest, posttest, control group design. A sample of 105 SS2 students from two schools was used for the study. Schools were purposively sampled from 28 public Schools in Zaria Education Zone. Students’ Creativity Assessment Test (SCAT) was adapted and used for data collection. Three null hypotheses were formulated to guide the study and were tested using ANCOVA at P < 0.05 level of significance. Results obtained revealed that students exposed to STS Instructional Approach, exhibited significantly higher level of creativity than those taught concept environmental conservation using Lecture Method. There is no significant difference in the creativity level of male and female students in the experimental group. Gender and treatment were found not to have any significant interaction effects on students’ level of creativity. On the basis of these findings, the study advocated for the teaching of Biology for creativity through innovative strategies like STS Approach
Structural and electrochemical properties of Reduced Graphene Oxide (RGO) synthesised using an improved modified hummers method as electrode material for electronics applications
High quality reduced graphene oxide (RGO) nanosheets were prepared from natural graphite using an improved modified Hummers method. The morphological, structural and electrochemical properties of the RGO were characterised by scanning electron microscope (SEM), Raman spectroscopy, X-ray diffraction (XRD) analysis, Cyclic Voltammetry (CV) analysis and Electrochemical Impedance Spectroscopy (EIS) analysis. The SEM image of the RGO showed that, there was a small increase in the number of grain boundaries, indicating a collapse of the surface coalescence of the graphene oxide. The XRD peak at 24.56Ëš corresponds to the (002) diffraction plane with the interlayer spacing along the c-axis of 2.0989 Çş. The Raman shift for the reduced graphene oxide gives the ID/IG intensity ratio of 1.04. The RGO exhibited good electrochemical characteristics with energy density and power density of 19.2 Whkg-1 and 149.3 Wkg-1 respectively.Keywords: Reduce Graphene Oxide, Structural Properties, Morphological Properties, electrochemical propertie
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Radio wave imaging using Ultra-Wide Band Spectrum Antennas for Near-Field Applications. Design, Development, and Measurements of Ultra-Wideband Antenna for Microwave Near-Field Imaging Applications by applying Optimisation Algorithms
The emergence of Ultra-wideband (UWB) technology application has yielded tremendous and vital impacts in the field of microwave wireless communications. These applications include military radar imaging, security screening, and tumour detection, especially for early detection of breast cancer. These indicators have stimulated and inspired many researchers to make the best use of this promising technology.
UWB technology challenges such as antenna design, the problem of imaging reconstruction techniques, challenges of severe signal attenuation and dispersion in high loss material. Others are lengthy computational time demand and large computer memory requirements are prevalent constraints that need to be tackled especially in a large scale and complex computational electromagnetic analysis. In this regard, it is necessary to find out recently developed optimisation techniques that can provide solutions to these problems.
In this thesis, designing, optimisation, development, measurement, and analysis of UWB antennas for near-field microwave imaging applications are considered. This technology emulates the same concept of surface penetrating radar operating in various forms of the UWB spectrum. The initial design of UWB monopole antennas, including T-slots, rectangular slots, and hexagonal slots on a circular radiating patch, was explicitly implemented for medical imaging applications to cover the UWB frequency ranging from 3.1 GHz to 10.6 GHz.
Based on this concept, a new bow-tie and Vivaldi UWB antennas were designed for a through-the-wall imaging application. The new antennas were designed to cover a spectrum on a lower frequency ranging from 1 GHz - 4 GHz to ease the high wall losses that will be encountered when using a higher frequency range and to guarantee deeper penetration of the electromagnetic wave. Finally, both simulated and calculated results of the designed, optimised antennas indicate excellent agreement with improved performance in terms of return loss, gain, radiation pattern, and fidelity over the entire UWB frequency. These breakthroughs provided reduced computational time and computer memory requirement for useful, efficient, reliable, and compact sensors for imaging applications, including security and breast cancer detection, thereby saving more lives.Tertiary Education Trust Fund (TET Fund)
Supported by the Nigerian Defence Academy (NDA
Frustrated network of indirect exchange paths between tetrahedrally coordinated Co in Ba2 CoO4
We present a detailed study of the electronic and magnetic interactions of Ba2CoO4, structurally very uncommon because of the isolated CoO4 distorted tetrahedral coordination. We show the presence of Co(d)-O(p) hybridized states characterized by spin polarized oxygen atoms, with their magnetic moments parallel to that on Co. The calculated isotropic exchange interaction parameters, which include the contributions from ligand spins, demonstrate the presence of a three-dimensional (3D) network of magnetic couplings that are partially frustrated in the identified magnetic ground state. Our results indicate that the dominant indirect exchange mechanism responsible for this ground state is mediated by O atoms along the Co-O »O-Co path
Effects of Mucilage on the Pasting, Thermal and Retrogradative Properties of Native and Modified Starches Obtained from Ipomoea Batatas
This study investigates the effect of mucilage on the pasting, thermal and retrogradative properties of native, pregelatinized and acid modified starches obtained from ipomoea batatas. Dispersions of mucilage with each starch was carried out in a ratio 1:20, 1:10, 1:5, 3:10 and 2:5 respectively. Native starch (SPS) had a higher peak viscosity, trough, breakdown, final viscosity and enthalpy (?H) as compared to pregelatinized starch (PPS) and acid modified starch (APS) in the order SPS > PPS > APS. Parameters such as pasting temperature, syneresis, onset, peak and conclusion temperature were in the order APS > PPS > SPS. Pregelatinized starch had a higher set back and peak time as compared to other starches in the order PPS > SPS > APS. Generally, dispersions of SPS, PPS and APS in mucilage followed similar trends as described above with increase in peak time, pasting temperature and ?H as the mucilage concentrations increased and a decrease in peak viscosity, trough, breakdown, final viscosity, set back, syneresis (except SPS), onset, peak and conclusion (except APS) temperature as the mucilage concentration increases. Keywords: Ipomoea batatas starch, pregelatinized, acid modified, dispersion, mucilag
Influence of Eu3+ dopant on physical and optical properties of lithium-borosulfophosphate glasses
Multi-components glass host with enhanced physical and optical features are greatly demanding for various photonics and optoelectronics devices. Selection of suitable glass former, modifier, and dopant ions with optimized composition is a key concern in the fabrication of novel optical glass materials for the aforementioned purpose. Thus, this work reports the convectional melt quench synthesis of europium (Eu3+) doped lithiumborosufophosphate glasses with composition 15Li2O-30B2O3-15SO3-(40-)P2O5-Eu2O3 (where = 0.1, 0.3, 0.5, 0.7 and 1.0 in mol%). The effect of P2O5 substitution by Eu2O3 on their physical (density, molar volume, ion concentration, polaron radius, inter-nuclear distance and field strength) and optical properties was examined. The amorphous nature of the samples was confirmed by XRD diffraction pattern. The density of glass samples was slightly increased with increasing concentration of Eu2O3. Such trend is attributed to the higher molecular weight of Eu2O3 (351.926 g/mol) than P2O5 (141.9445 g/mol). The room temperature absorption spectra revealed four weak bands in the UV-Vis range and two strong bands in the NIR range with 1.0 mol% glass sample possessing the highest intensity at 7F0→7F6 (2095 nm). Incorporation of Eu3+ ion significantly enhanced the glass absorbance and the physical properties. The results on high refractive index (~2.3), polarizability and non-linear physical features suggest that these glasses are potential for photonics and solid-state laser applications.Keywords: Borosulfophosphate glasses, Europium ions, physical properties, optical properties and photoluminescenc
The effect of Carica papaya seed extracts on urea, creatinine and uric acid levels in Wistar rats
This study investigated the effect of Carica papaya seeds on renal function parameters. Male Wistar rats aged 7± 1weeks, and weighing 70.0-105.0g, were used for the study and the animals were divided into four groups -A, B, C and D. Group A served as control, while B, C and D, served as test groups. The test groups were further subdivided into three -B1 – B3, C1 – C3 and D1 – D3 (n=4 each) and they received a combination of both ripe and unripe Carica papaya seeds; ripe Carica papaya seeds only; and unripe Carica papaya seeds only, respectively. At the end of the experimental period of six (6) weeks, blood samples were obtained from the groups and analyzed for urea, creatinine and uric acid levels using standard methods. The statistical analysis of the data obtained was performed using the SPSS package (version 20) and results showed a dosage dependent and statistically significant increase in urea, creatinine and uric acid levels irrespective of the type; suggesting that Carica papaya’s has capacity to induce alterations in renal function. Thus, there is an urgent need to regulate the inclusion of Carica papaya seeds in herbal preparations; particularly in those used for the management of kidney diseases.Keywords: Carica papaya, Urea. Creatinine, Uric acid, Renal functio
The effect of Carica papaya seed extract on the histology of the kidney in Wister rats
This study was carried out to investigate the effect of ripe and unripe carica papaya seeds on the histology of the kidney in male Wister rats. The animals were divided into four groups -A, B, C and D, with group A serving as control, while groups B,C and D served as test groups. The test groups were further subdivided into three -B1 – B3, C1 – C3 and D1 – D3 (n=4 each respectively) and the subgroups received a combination of ripe and unripe Carica papaya seeds; ripe Carica papaya seeds only; and unripe Carica papaya seeds only, respectively. At the end of the experimental period of six (6) weeks, the animals were sacrificed to harvest the kidneys for histological studies. Microscopic examinations of the respective kidney tissue sections revealed dosage dependent cytoarchitectural distortions across the groups especially in group D, where severe hemorrhagic signs, glomerular shrinkage, inflammatory cell infiltration, tubular wall disruption, and glomerular degenerations were observed. The results suggests that Carica papaya seed can best be classified as a dosage-dependent nephrotoxic or non-nephrotoxic agent and its cautious inclusion in herbal drug therapy is unequivocally recommended.Key-words: Carica papaya, chymopopain, kidneys, nephrotoxic, papai
Efficacy of Acid-treated Sawdust in Decolourization of Tanning Wastewater
Colour removal from dye-bearing effluent is a serious challenge due to the difficulty in treating such wastewater by conventional treatment methods. The present investigation explores the decolourization of contaminated wastewater using acid-activated sawdust as an adsorbent. The physicochemical properties of wastewater samples labelled A, B, and C vizaverage temperature; pH; electrical conductivity; and total dissolved solids were determined using standard methods to be 302.63; 6.1; 284.47 µS/cm;35116.66 mg/L respectively. Colour removal efficiency of the adsorbent was studied under variable conditions (contact time, rate of agitation,loading). Experimental results demonstrated that the sawdust adsorbent has a significant capacity for colour removal from tannery effluent. There was significant variation in the absorbance of the treated samples. Adsorbent dose, stirring rate, and contact time were found to be directly proportional to colour removal while pH variation of the samples show that the effluents became less alkaline (slightly acidic) after decolourization
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