121 research outputs found

    Extension of the Method of Direct Separation of Motions for Problems of Oscillating Action on Dynamical Systems

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    AbstractA general approach to study oscillating action on nonlinear dynamical systems is developed. It implies a transition from initial governing equations of motion to much more simple equations describing only the main slow component of motions (the vibro-transformed dynamics equations). The approach is named as the Oscillatory Strobodynamics, since motions are perceived as under a stroboscopic light. The vibro-transformed dynamics equations comprise terms that represent the averaged effect of the oscillating action. The method of direct separation of motions (MDSM) appears to be an efficient and simple tool to derive these equations. A modification of the method applicable to study problems that do not imply restrictions on the spectrum of excitation frequencies is proposed. It allows also to abandon other restrictions usually introduced when employing the classical asymptotic methods, e.g. the requirement for the involved nonlinearities to be weak.Several relevant examples from Mechanics, Physics, Chemistry, and Biophysics are considered by means of the conventional MDSM and, in more details, by the modified MDSM, illustrating the efficiency the methods

    Revisiting the models of vibration screening process

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    This talk presents two approaches for modeling of the vibration screening process. The first approach is analytical. It models the screening process as a diffusion of undersize fraction taking into account the special term for vibration separation (the Brazil nut effect). The talk provides a solution of the corresponding partial differential equation. The solution in turn allows estimation of the screening performance dependence on both deterministic and stochastic factors as well as evaluation of the factors dominance conditions. The talk presents simple evaluation formulae for the screening process performance. The second approach is based on a simulation model. The model deals with monolayer dynamics. Embodying traditional concepts of vibration transportation, the approach introduces some novel techniques of evaluation of the effect of the granular particles shape. Taking into account the particle shape factor may significantly improve the modeling precision for nonspherical particles

    The Effect of Rational Emotive Behaviour Therapy on Work-irrational Beliefs Among Electrical and Electronic Educators in Nigeria

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     This study delved into a critical concern in academic and professional settings: the impact of irrational work-related beliefs among individuals within the Electrical/Electronic Technology Education domain in Nigeria. The prevalence of detrimental work-related beliefs and their potential adverse effects on performance, mental health, and overall well-being necessitated an investigation into effective therapeutic interventions to mitigate these beliefs. The research adopted a quasi-experimental design spanning eight weeks and involving 16 sessions to examine the effects of Rational Emotive Behavioural Therapy (REBT) on these work-related irrational beliefs. The study encompassed a cohort of 330 participants, comprising Electrical/Electronic Technology Education technologists and instructors within Nigerian universities. To ensure a robust study design, the participants were randomly allocated to the REBT group (165 participants) or the control group (165 participants). The study uncovered notable findings using an intervention package and structured psycho-educational strategies for data collection. The analysis revealed a significant mean difference between the experimental (REBT) group and the control group, demonstrating the efficacy of REBT in significantly reducing work-related belief scores among Electrical and Electronic Technologists compared to those not exposed to the therapy. Furthermore, the study explored potential variations based on gender in response to the treatment, finding that the interaction effect of therapies and gender was not statistically significant. This suggests that the benefits of REBT in alleviating work-related irrational beliefs were consistent across genders. These findings underscore the potential of REBT as an effective intervention to address work-related irrational beliefs. The study recommends the integration of REBT into the academic curriculum, emphasising its value in mitigating detrimental work-related beliefs among educational staff and students in the field of Electrical/Electronic Technology Education

    Isolation of Quarcetin-3-O-β-D-glucopyranoside from the ethanol leaf extract of Ficus sycomorous L. (Moracaea)

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    Ficus sycomorous (Sycamore fig.) Family Moraceae is a plant used in African traditional medicine to treat mental illness, dysentery, cough, diarrhea, tuberculosis and Cancer. In this research work the leaf of the plant was subjected to cold maceration using 75% ethanol. The extract was fractionated using n- hexane, chloroform ethylacetate and n-butanol. The ethylacetate fraction was subjected to column chromatographic separation and purification. Quarcetin-3-O-β-D-glucopyranoside was isolated and the structure of the compound was elucidated by various spectral techniques such as1 and 2D NMR and mass spectrometry. Keyword: Ficus sycomorous, Moraceae, NMR, Quarcetin-3-O-β-D-glucopyranosid

    Thermoelectric enhancement in PbTe with K, Na co-doping from tuning the interaction of the light and heavy hole valence bands

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    The effect of K and K-Na substitution for Pb atoms in the rock salt lattice of PbTe was investigated to test a hypothesis for development of resonant states in the valence band that may enhance the thermoelectric power. We combined high temperature Hall-effect, electrical conductivity and thermal conductivity measurements to show that K-Na co-doping do not form resonance states but2 can control the energy difference of the maxima of the two primary valence sub-bands in PbTe. This leads to an enhanced interband interaction with rising temperature and a significant rise in the thermoelectric figure of merit of p-type PbTe. The experimental data can be explained by a combination of a single and two-band model for the valence band of PbTe depending on hole density that varies in the range of 1-15 x 10^19 cm^-3.Comment: 8 figure

    DETERMINANTS OF BROILER PRODUCTION AND ITS EFFECTS ON POVERTY STATUS AMONG CIVIL SERVANTS IN JOS METROPOLIS, PLATEAU STATE, NIGERIA

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    The research was carried out to analyze broiler production as a sustainable tool in reducing poverty among civil servants in Plateau State, Nigeria. The specific objectives were to: determine the profitability of broiler production; evaluate the poverty status and the effect of broiler income on the poverty status of the civil servants; identify the socio-economic factors influencing the level of broiler production; and describe the constraints of broiler production. Data from 120 members of Poultry Association of Nigeria (PAN) who are civil servants, were analysed using descriptive and inferential statistics. Majority of the civil servants that engaged in broiler farmers were women. Findings revealed that the influx of new entrants into broiler production in recent times was due to the ban on importation of frozen poultry product by the Federal Government of Nigeria which create high demand-supply gap. The civil servants’ broiler producers earned a profit margin of 58% and return on investment of ₦1.67 per Naira invested. This resulted into reduced FGT poverty indices. The level of broiler production were significantly determined by sex, level of education and experience at different level of probability. Likewise, the poverty status of the civil servants were significantly affected by salary and income from broiler production at 1 and 5 % levels of probability. Major constraints in broiler production were high cost of feed and vaccines. Government ban on importation of poultry meat is plausible and should be further imbibed by the Nigerian citizens to consume home grown poultry meat

    The beneficial role of resveratrol on chlorpyrifos-induced cognitive impairment and lipid peroxidation biomarker in Swiss albino mice

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    Chlorpyrifos (CPF) has been associated with cognitive and psychomotor impairments in both humans and animals. This cognitive impairment has been linked to its enhanced reactive oxygen species (ROS) generating capacity. Therefore, antioxidant treatment may provide a novel therapeutic window for the management of these related impairments. The aim of this work was to evaluate the beneficial role of resveratrol on chlorpyrifos-induced cognitive impairment and lipid peroxidation biomarker in Swiss albino mice. Swiss albino mice were divided into (6) six groups of five each (n=5). Group I served as the control and were administered olive oil (2 ml/kg), group II received carboxymethylcellulose (CMC) 10 mg/kg, group III received resveratrol 30 mg/kg, group IV received chlorpyrifos (CPF) 3 mg/kg, group V received CPF (3 mg/kg) after the oral administration of resveratrol (30 mg/kg) and group VI received Vitamin E (Vit E) 100 mg/kg All administrations were done by oral gavage for a duration of 21 days. Cognitive function was assessed using Y-maze,and Novel object recognition tests and oxidative stress was evaluated using oxidative biomarkers techniques.The results obtained showed that resveratrol at dose 30 mg/kg significantly(p<0.05) improved cognitive impairment and significantly decreased (p<0.05) malondialdehyde (MDA) concentration when compared with the control. In conclusion, 30mg/kg resveratrol suppressed memory impairment, decreased malondialdehyde levels, increased catalase activity, superoxide dismutase activity and glutathione levels in our chlorpyrifos-induced cognitive impairment mice model.Keywords: cognition, chlorpyrifos, resveratrol, memor

    Memory deficits in APP23/Abca1+/− mice correlate with the level of Aβ oligomers

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    ABCA1, a member of the ATP-binding cassette family of transporters, lipidates ApoE (apolipoprotein A) and is essential for the generation of HDL (high-density lipoprotein)-like particles in the CNS (central nervous system). Lack of Abca1 increases amyloid deposition in several AD (Alzheimer's disease) mouse models. We hypothesized that deletion of only one copy of Abca1 in APP23 (where APP is amyloid precursor protein) AD model mice will aggravate memory deficits in these mice. Using the Morris Water Maze, we demonstrate that 2-year-old Abca1 heterozygous APP23 mice (referred to as APP23/het) have impaired learning during acquisition, and impaired memory retention during the probe trial when compared with age-matched wild-type mice (referred to as APP23/wt). As in our previous studies, the levels of ApoE in APP23/het mice were decreased, but the differences in the levels of Aβ and thioflavin-S-positive plaques between both groups were insignificant. Importantly, dot blot analysis demonstrated that APP23/het mice have a significantly higher level of soluble A11-positive Aβ (amyloid β protein) oligomers compared with APP23/wt which correlated negatively with cognitive performance. To confirm this finding, we performed immunohistochemistry with the A11 antibody, which revealed a significant increase of A11-positive oligomer structures in the CA1 region of hippocampi of APP23/het. This characteristic region-specific pattern of A11 staining was age-dependent and was missing in younger APP23 mice lacking Abca1. In contrast, the levels of Aβ*56, as well as other low-molecular-mass Aβ oligomers, were unchanged among the groups. Overall, the results of the present study demonstrate that in aged APP23 mice memory deficits depend on Abca1 and are likely to be mediated by the amount of Aβ oligomers deposited in the hippocampus
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