57 research outputs found

    Trajectory Optimization of Quadrotor-UAV Drone Using Genetic Algorithm

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    Unmanned Aerial Vehicles (UAVs) Technology recently attracts attention of many researchers; this is due toits numerous potentialities in civil application. One of the key areas of interest by researches is how to achievea total talent of “Sense and Avoid” in the UAV which will enhance safe and efficient trajectory of the vehicle.This is why this paper is going to use an optimization technique to optimize trajectory path of the UAV flight.The chosen optimization algorithm is Genetic algorithm (GA) which is going to be use to optimize the trajectoryof UAV by determine the shortest path of flight as well as obstacle-free path in order to save energy and timeduring flight. MATLAB and Simulink are used to simulate as well as evaluate the algorithm. In the result fromthe experiment, it appeared that an optimized trajectory path is tremendously better than path from the firstrandomly generated population in term of distance covered as well as time taken before triumph the target pointfrom the initial point

    Preliminary phytochemical screening and antioxidant activity of leave extract of Albizia chevalieri harms (Leguminoseae-Mimosoideae)

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    Antioxidant evaluation of Albizia chevalieri used in Northern Nigerian traditional medicine, was carried out using the free radical scavenging activity of the 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH), total phenolics content and reducing power assay on the methanol leave extract. The results of the DPPH scavenging activity study indicate a concentration dependent antioxidant activity with 59.588, 68.477, 77.240, 85.925 and 94.732% of various concentrations of 10, 25, 50, 125 and 250μg/ml of the extract respectively. The total phenolic content was found to be 60.20 mg/g Gallic acid equivalent (GAE) and the reducing power of 0.071±0.03nm was obtained. The DPPH scavenging activity of the extract was found to be promising. There is no significant difference (

    Comparative Study of Maximum Power Point Tracking with a Modified DC DC Converter

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    Maximum power points are used to find the voltages and currents at which a photovoltaic (PV) panel should operate to obtain maximum power. In order to deliver highest power, an efficient DC DC converter and a reliable tracking algorithm are used. There is also the need to continuously find the maximum power under any environmental conditions at all times. This research is intended to study a comparative performance of maximum power point (MPP) which is presented under uniform irradiance condition. The algorithm employed is an improved cuckoo search algorithm and the DC-DC Converter( switched mode power supply) has been modified by including a synchronous rectifier connected to a load, the performance of the system is validated using MATLAB/Simulink and practical implementation for this work. A comparison of the MATLAB Simulation with the practical implementation of MPP is presented using maximum power and percentage tracking efficiency as performance metric. From the MATLAB results obtained, maximum extracted power is 26.81W and the hardware implementation gives a maximum power of 28.71W. Tracking efficiency improves by 6.62%. The results show the practical MPP gives a better maximum power, which consequently improves the Photovoltaic systems efficiency and conversely mitigates the power consumption and the cost of the system than the simulation result obtained in MATLAB

    Influence of socio-demographic variables on the choice of contraceptives among women attending ANC unit at specialist hospital Sokoto, Sokoto State, Nigeria

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    Background: A contraceptive choice that couples make is a key component of the Sustainable Development Goal agenda and a major contributor to national health. In spite of the importance of increased contraceptive uptake among couples of reproductive ages, meeting the reproductive health rights of women remains an issue due to multi-faceted obstacles within complex environments. The issues which impact women’s reproductive health rights in relation to contraception relate to availability, accessibility, affordability, literacy, tradition, and culture. This study explores the influence of socio-demographic data on the choice of contraceptives among women who are accessing family planning services at a Specialist hospital, Sokoto-Nigeria.Methods: A cross sectional study was used in this quantitative research to generate data on contraceptive choices of women within the reproductive age (18-49 years) who are accessing family planning services at Specialist hospital, Sokoto. A structured questionnaire was used to elicit information from 352 respondents who were randomly sampled at a Specialist hospital, Sokoto-Nigeria. Data was analyzed using SPSS version 20.0. Descriptive statistics, correlation and regression analyses were used in the data analyses.Results: The findings of this study established age, occupation and level of education to be related with the usage and choice of contraceptives among women attending family planning unit at a Specialist hospital in Sokoto.Conclusions: The result of the study indicated that the socio–demographic data of the respondent, has a significant role in the choice of contraceptives among the women attending family planning unit of Specialist Hospital Sokoto

    Optimization of electrical discharge machining parameters of SiSiC through response surface methodology

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    In recent years, researchers have demonstrated increases interest in studies involving silicon carbide (SiC) materials due to several industrial applications. Extreme hardness and high brittleness properties of SiC make the machining of such material very difficult, time consuming and costly. Electrical discharge machining (EDM) has been regarded as the most viable method for the machining of SiC. The mechanism of EDM process is complex. Researchers have acknowledged a challenge in generating a model that accurately describes the correlation between the input parameters and the responses. This paper reports the study on parametric optimization of siliconized silicon carbide (SiSiC) for the following quality responses; material removal rate (MRR), tool wear ratio (TWR) and surface roughness (Ra). The experiments were planned using Face centered central composite design. The models which related MRR, TWR and Ra with the most significant factors such as discharge current (Ip), pulse-on time (Ton), and servo voltage (Sv) were developed. In order to develop, improve and optimize the models response surface methodology (RSM) was used. Non-linear models were proposed for MRR and Ra while linear model was proposed for TWR. The margin of error between predicted and experimental values of MRR, TWR and Ra are found within 6.7, 5.6 and 2.5% respectively. Thus, the excellent reproducibility of this experimental study is confirmed, and the models developed for MRR, TWR and Ra are justified to be valid by the confirmation tests

    Effects of zinc oxide nanoparticles on viscosity of transesterified neem oil

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    Efforts have been made worldwide to find alternative fluids for industrial applications. Vegetable oil appears to be a perfect alternative, but using most of the vegetable oil as a feedstock made its use for industrial purposes challenging. The recent trend is to develop coolants/lubricants from non-edible seed oil. This work investigates the effects of zinc oxide nanoparticles on viscosity of transesterified neem oil. The crude neem oil was purified, transesterified and nanoparticles were dispersed in the transesterified oil at concentrations ranging from 0.0% to 1.0% at 0.2% intervals. Fourier Transform Infrared (FTIR) spectra were used to examine the structures of the samples and Scanning Electron Microscopy (SEM) analyses were used to examine the surface morphology of the samples. Viscosity were examined. Among other things, it was found that a small amount of ZnO (0.6%) nanoparticles in the oil could improve the viscosity of the fluid. The nanoliquid with a ZnO concentration of 0.6% appears to have optimal properties

    Capacity Building for Primary Stroke Prevention Teams in Children Living With Sickle Cell Anemia in Africa

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    Background: Nigeria has the highest proportion of children with sickle cell anemia (SCA) globally; an estimated 150,000 infants with SCA are born annually. Primary stroke prevention in children with SCA must include Nigeria. We describe capacity-building strategies in conjunction with two National Institutes of Health–funded primary stroke prevention trials (a feasibility trial and phase III randomized controlled trial) with initial hydroxyurea treatment for children with SCA and abnormal transcranial Doppler (TCD) velocities in Nigeria. We anticipated challenges to conducting clinical trials in a low-resource setting with a local team that had not previously been involved in clinical research and sought a sustainable strategy for primary stroke prevention. Methods: This is a descriptive, prospective study of challenges, solutions, and research teams in two trials that enrolled a total of 679 children with SCA. Results: As part of the capacity-building component of the trials, over eight years, 23 research personnel (physicians, nurses, research coordinators, a statistician, and a pharmacist) completed a one-month research governance and ethics training program at Vanderbilt University Medical Center, USA. A lead research coordinator for each site completed the Society of Clinical Research Professionals certification. TCD machines were donated; radiologists and nonradiologists were trained and certified to perform TCD. A scalable E-prescription was implemented to track hydroxyurea treatment. We worked with regional government officials to support ongoing TCD-based screening and funding for hydroxyurea for children with SCA at a high risk of stroke. Conclusions: Our trials and capacity building demonstrate a sustainable strategy to initiate and maintain pediatric SCA primary stroke prevention programs in Africa

    Prevalence and Determinants of Endothelial Dysfunction among Adults Living with HIV in Northwest Nigeria

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    Background: Endothelial dysfunction constitutes an early pathophysiological event in atherogenesis and cardiovascular disease. This study aimed to assess the prevalence, determinants, and degree of endothelial dysfunction in antiretroviral therapy (ART)–treated people living with HIV (PLWH) in northwestern Nigeria using brachial flow-mediated dilatation (FMD). Methods: This was a comparative, cross-sectional study. A total of 200 ART-treated adults living with HIV with no evidence of kidney disease were compared with 200 HIV-negative participants attending a tertiary hospital in Kano, Nigeria, between September 2020 and May 2021. Endothelial function was evaluated by measuring FMD with a high-resolution vascular ultrasound transducer. FMD was calculated as the ratio of the brachial artery diameter after reactive hyperemia to baseline diameter and expressed as a percentage of change. Blood and urine samples were obtained from participants in both arms. Urine albumin-to-creatinine ratio (uACR) was calculated using the 2021 CKD-EPI estimated glomerular filtration rate (eGFR) creatinine-cystatin C equation without the race variable, and low-density lipoprotein (LDL) cholesterol was measured using enzymatic method. Results: The overall mean age (± standard deviation) of the study participants was 42 ± 11 years. Participants in the comparison arm were younger than PLWH (38 ± 11 versus 46 ± 10 years, respectively). The median (interquartile range) uACR was 41.6 (23.2–162.9) mg/g for the ART-treated PLWH versus 14.5 (7.4–27.0) mg/g for healthy controls. PLWH had a significantly lower mean percent FMD when compared to HIV-negative participants (9.8% ± 5.4 versus 12.1% ± 9.2, respectively). Reduced FMD was independently associated with HIV infection (β = –2.83%, 95% CI, –4.44% to –1.21%, p = 0.001), estimated glomerular filtration rate (β = –0.04%, 95% CI, –0.07% to –0.01%, p = 0.004) and LDL cholesterol (β = –1.12%, 95% CI, –2.13% to –0.11%, p = 0.029). Conclusion: HIV-positive status, lower estimated GFR, and higher LDL cholesterol levels were independently associated with endothelial dysfunction. Future prospective studies with larger cohorts of persons living with HIV (and age- and sex-matched HIV-negative controls) are needed to gain further insight into these important findings. In the interim, aggressive management of modifiable risk factors is warranted
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