Operation of Circuit Breakers: Data and Analysis

[EN] An attempt has been made for the analysis on Circuit breakers (CBs) this paper. First, the types and arcing phenomenon of Oil and SF6 Circuit breakers were briefly discussed. However, various CBs were analyzed in terms of certain outage frequencies and reliability indices to ascertain the most reliable CB. This was possible using data collected from the 33kV Transmission Company of Nigeria (TCN) New Haven, Enugu. After the analysis, Emene Industrial CB had the highest value of availability of 0.9999 and the lowest tripping report while Ezillo had the highest failure rate of 0.1032.The authors are immensely grateful for the financial support from “African Centre of Excellence (ACE-SPED) University of Nigeria, Nsukka” to enable us to achieve the research (Muncho J. Mbunwe et al., 2019-2021).Madueme, VC.; Mbunwe, MJ.; Madueme, TC.; Ahmad, MA.; Anghel Drugarin, CV. (2021). Operation of Circuit Breakers: Data and Analysis. Multidisciplinary Journal for Education, Social and Technological Sciences. 8(2):60-73. https://doi.org/10.4995/muse.2021.12406OJS607382Anyaka, B.O. (2012). Reliability and Maintainability of Power System [Lecture Note]. http://engineering.unn.edu.ngCircuit globe, (n.d.). Circuit breaker, Retrieved June 10, 2017, from open source:- http://circuitglobe.com/circuit-breaker.htmlElectrical concepts, Circuit breaker and Arc Phenomenon, (n.d.). Retrieved June 10, 2017, from open source: http://electricalbaba.com/circuit-breaker-and-arc-phenomenon/Electrical Systems, (n.d.). Retrieved June 10, 2017, from open source: http://skm-eleksys.com/2012/02/sf6-circuit-breaker-working.htmlKezunovic, M. Ren, Z. Latisko, G. Sevcik, D.R. Lucey, J.S. Cook, W.E. and Koch, E.A. (2005). Automated Monitoring and Analysis of Circuit Breaker Operation, IEEE Transactions on Power Delivery, 20(3), p. 1910. https://doi.org/10.1109/TPWRD.2005.848466Pinnekamp, F. (2007). The circuit breaker: a showcase of industrial product development, Transmission group R&D and technology, ABB, Switzerland, p.31. https://new.abb.com/docs/default-source/technology/brosch%C3%BCre-chchrc2017final-einseitig-(002).pdf?sfvrsn=e3f37d14_2Saxena, S. Singh, A. Ali, M. Gandhi, K. (2012). Various Types of Circuit Breakers used in Power System for Smooth Working of the Transmission Line, MIT International Journal of Electrical and Instrumentation Engineering, 2(2), p. 106. https://www.semanticscholar.org/paper/06918326da2b2ac6fd80620d88961b68554b72edSuwanasri, T. Hlaing, M.T. and Suwanasri, C. (2014). Failure Rate Analysis of Power Circuit Breaker in High Voltage Substation, GMSARN International Journal, 8(1), 1-6. http://gmsarnjournal.com/home/journal-vol/journal-vol-8-no-1/Transmission Company of Nigeria. (2016). Tripping reports April - June 2016 [Unpublished Raw data]. New Haven, Enugu, Nigeria. https://www.tcn.org.ng/page_history.phpMuncho J. Mbunwe, M. Ayaz Ahmad, Syed Khalid Mustafa. (2020). An effective energy saving design strategy to maximize the use of electricity, J. Math. Comput. Sci., 10(5), 1808-1833, https://doi.org/10.28919/jmcs/4775Mbunwe Muncho J., Ezema Ejiofor E., Ngwu Anene A., C V Anghel Drugarin, M. Rehan Ajmal, M Ayaz Ahmad. (2021). Characterization of three phase solid state VAR compensation scheme in three phase pulse width modulation voltage source inverter, Journal of Physics: Conference Series, Vol. 1781, 012034, https://doi.org/10.1088/1742-6596/1781/1/012034M. Ayaz Ahmad, Irina Tvoroshenko, Jalal Hasan Baker, Vyacheslav Lyashenko. (2019). Modeling the Structure of Intellectual Means of Decision-Making Using a System Oriented NFO Approach, International Journal of Emerging Trends in Engineering Research , Vol. 7(11), 460-465. https://doi.org/10.30534/ijeter/2019/107112019Mykhailo Kopot, M. Ayaz Ahmad, Vyacheslav Lyashenko, Syed Khalid Mustafa. (2020). Prospects for Creating Sub-Millimeter Magnetrons, International Journal of Advanced Trends in Computer Science and Engineering, Vol. 9(4), 6184-6188. https://doi.org/10.30534/ijatcse/2020/294942020M. Ayaz Ahmad, Irina Tvoroshenko, Jalal Hasan Baker, Vyacheslav Lyashenko. (2019). Computational Complexity of the Accessory Function Setting Mechanism in Fuzzy Intellectual Systems, International Journal of Advanced Trends in Computer Science and Engineering, Vol. 8(5), 2370-2377. https://doi.org/10.30534/ijatcse/2019/77852019Muncho J. Mbunwe, Udochukwu B. Akuru, Hilary U. Ezea, Ogbonnaya I. Okoro, M. Ayaz Ahmad. (2020). Some Aspects of Future Energy Generation in Using of Solar Power Satellites, Int. J. Anal. Appl., 18 (1), 117-128. https://doi.org/10.28924/2291-8639-18-2020-11

A problem-solving task specialized for functional neuroimaging: Validation of the Scarborough adaptation of the Tower of London (S-TOL) using near-infrared spectroscopy

Problem-solving is an executive function subserved by a network of neural structures of which the dorsolateral prefrontal cortex (DLPFC) is central. Whereas several studies have evaluated the role of the DLPFC in problem-solving, few standardized tasks have been developed specifically for use with functional neuroimaging. The current study adapted a measure with established validity for the assessment of problem-solving abilities to design a test more suitable for functional neuroimaging protocols. The Scarborough adaptation of the Tower of London (S-TOL) was administered to 38 healthy adults while hemodynamic oxygenation of the PFC was measured using 16-channel continuous-wave functional near-infrared spectroscopy (fNIRS). Compared to a baseline condition, problems that required two or three steps to achieve a goal configuration were associated with higher activation in the left DLPFC and deactivation in the medial PFC. Individuals scoring higher in trait deliberation showed consistently higher activation in the left DLPFC regardless of task difficulty, whereas individuals lower in this trait displayed less activation when solving simple problems. Based on these results, the S-TOL may serve as a standardized task to evaluate problem-solving abilities in functional neuroimaging studies

Treatment of wastewater by natural systems

Abstract Experimental results from a pilot-scale constructed wetland (CW) treatment plant have been described. The study was conducted at two different systems: continuous and batch. In the continuous system, the treatment yields were monitored in different loading conditions in 1-year period. The pilot plant consists of two serially connected tanks settled up with fillers; Cyperus was used as treatment media and wastewater between the two tanks was recycled periodically. Chemical oxygen demand (COD) and suspended solid (SS) removal efficiencies were obtained as 90% and 95%, respectively. The effluent COD concentration at an average loading of 122 g COD/m 2 day was satisfactory for the Turkish Water Pollution Control Regulation. This means that a 0.8 m 2 of garden area per person is required. Other removal values for the same conditions were as follows: total Kjeldahl nitrogen (TKN) was 77%, total nitrogen (TN) was 61%, and PO 4 3 À -P was 39%. The batch experimental systems consist of 12 pairs of serially connected tanks, with each pair having a surface area of 1 m 2 . Each set was filled with sewage once a day, and the wastewater between the paired tanks was recycled periodically by the pump. Each pair of tanks was filled with materials such as gravel, peat, and perlite. Seven of them were vegetated with Phragmites, Cyperus, Rush, Iris, Lolium, Canna, and Paspalum, while the other five were not seeded. The best performances were obtained by Iris for COD (% 94), by Canna for ammonia nitrogen (% 98), and by Iris for total nitrogen (% 90) and phosphorus (% 55) removal.

Ultracompact microinterferometer-based fiber Bragg grating interrogator on a silicon chip

We report an interferometer-based multiplexed fiber Bragg grating (FBG) interrogator using silicon photonic technology. The photonic-integrated system includes the grating coupler, active and passive interferometers, interferometers, a 12-channel wavelength-division-multiplexing (WDM) filter, and Ge photodiodes, all integrated on a 6x8 mm2 silicon chip. The system also includes optical and electric interfaces to a printed board, which is connected to a real-time electronic board that actively performs the phase demodulation processing using a multitone mixing (MTM) technique. The device with active demodulation, which uses thermally-based phase shifters, features a noise figure of σ  =  0.13 pm at a bandwidth of 700 Hz, which corresponds to a dynamic spectral resolution of 4.9 fm/Hz1/2. On the other hand, the passive version of the system, based on a 90º-hybrid coupler, features a noise figure of σ  =  2.55 pm at a bandwidth of 10 kHz, also showing successful detection of a 42 kHz signal when setting the bandwidth to 50 kHz. These results demonstrate the advantage of integrated photonics, which allows the integration of several systems with different demodulation schemes in the same chip and guarantees easy scalability to a higher number of ports without increasing the dimensions or the cost

Status of the differential transformation method

Further to a recent controversy on whether the differential transformation method (DTM) for solving a differential equation is purely and solely the traditional Taylor series method, it is emphasized that the DTM is currently used, often only, as a technique for (analytically) calculating the power series of the solution (in terms of the initial value parameters). Sometimes, a piecewise analytic continuation process is implemented either in a numerical routine (e.g., within a shooting method) or in a semi-analytical procedure (e.g., to solve a boundary value problem). Emphasized also is the fact that, at the time of its invention, the currently-used basic ingredients of the DTM (that transform a differential equation into a difference equation of same order that is iteratively solvable) were already known for a long time by the "traditional"-Taylor-method users (notably in the elaboration of software packages --numerical routines-- for automatically solving ordinary differential equations). At now, the defenders of the DTM still ignore the, though much better developed, studies of the "traditional"-Taylor-method users who, in turn, seem to ignore similarly the existence of the DTM. The DTM has been given an apparent strong formalization (set on the same footing as the Fourier, Laplace or Mellin transformations). Though often used trivially, it is easily attainable and easily adaptable to different kinds of differentiation procedures. That has made it very attractive. Hence applications to various problems of the Taylor method, and more generally of the power series method (including noninteger powers) has been sketched. It seems that its potential has not been exploited as it could be. After a discussion on the reasons of the "misunderstandings" which have caused the controversy, the preceding topics are concretely illustrated.Comment: To appear in Applied Mathematics and Computation, 29 pages, references and further considerations adde

Nitric Oxide Contributes to Vasomotor Tone in Hypertensive African Americans Treated With Nebivolol and Metoprolol

Endothelial dysfunction is more prevalent in African Americans (AAs) compared with whites. The authors hypothesized that nebivolol, a selective β1 -antagonist that stimulates nitric oxide (NO), will improve endothelial function in AAs with hypertension when compared with metoprolol. In a double-blind, randomized, crossover study, 19 AA hypertensive patients were randomized to a 12-week treatment period with either nebivolol 10 mg or metoprolol succinate 100 mg daily. Forearm blood flow (FBF) was measured using plethysmography at rest and after intra-arterial infusion of acetylcholine and sodium nitroprusside to estimate endothelium-dependent and independent vasodilation, respectively. Physiologic vasodilation was assessed during hand-grip exercise. Measurements were repeated after NO blockade with L-N(G) -monomethylarginine (L-NMMA) and after inhibition of endothelium-derived hyperpolarizing factor (EDHF) with tetraethylammonium chloride (TEA). NO blockade with L-NMMA produced a trend toward greater vasoconstriction during nebivolol compared with metoprolol treatment (21% vs 12% reduction in FBF, P=.06, respectively). This difference was more significant after combined administration of L-NMMA and TEA (P\u3c.001). Similarly, there was a contribution of NO to exercise-induced vasodilation during nebivolol but not during metoprolol treatment. There were significantly greater contributions of NO and EDHF to resting vasodilator tone and of NO to exercise-induced vasodilation with nebivolol compared with metoprolol in AAs with hypertension

Experiences of wearing support garments by people living with a urostomy

BACKGROUND:support garments are commonly worn by people with a urostomy but there are no published data about their experiences of doing so. AIMS:to identify the views of people living with a urostomy on the role of support garments. METHODS:a cross-sectional survey of the stoma population's experiences of support garments was conducted in 2018. Recruitment was by social media. The free-text responses provided by a sub-sample of 58 people out of 103 respondents with a urostomy, were analysed. FINDINGS:thematic analysis revealed four themes: physical self-management; psychosocial self-management; lifestyle; and healthcare advice and support. There were mixed feelings about the value of support garments. Many cited a sense of reassurance and confidence and being able to be more sociable and active; others reported discomfort and uncertainty about their value. CONCLUSION:these findings add new understanding of experiences of support garments and provide novel theoretical insights about life with a urostomy

Precariousness, gender, resistance and consent in the face of global production network’s ‘Reforms’ of Pakistan’s garment manufacturing industry

This case study of the restructuring of Pakistan’s garment manufacturing industry explores how attempts to increase capital’s control over the labour process intersect with local patriarchal structures and trigger workers’ reflexivity and agency causing unanticipated consequences. Using Archer’s notion of agency, the article examines the theoretical space where capitalism meets patriarchy, and both are reproduced. The focus on reflexivity, anchored between objective contexts and agents’ personal concerns, helps theorize capital–labour–gender relations in global supply chains and explains workers’ impactful resistance to protect a supposedly precarious work regime. Our findings challenge the notion that globalization reduces workers’ agency and their potential for impactful resistance

Glutathione and glutamate in schizophrenia: a 7T MRS study

In schizophrenia, abnormal neural metabolite concentrations may arise from cortical damage following neuroinflammatory processes implicated in acute episodes. Inflammation is associated with increased glutamate, whereas the antioxidant glutathione may protect against inflammation-induced oxidative stress. We hypothesized that patients with stable schizophrenia would exhibit a reduction in glutathione, glutamate, and/or glutamine in the cerebral cortex, consistent with a post-inflammatory response, and that this reduction would be most marked in patients with “residual schizophrenia”, in whom an early stage with positive psychotic symptoms has progressed to a late stage characterized by long-term negative symptoms and impairments. We recruited 28 patients with stable schizophrenia and 45 healthy participants matched for age, gender, and parental socio-economic status. We measured glutathione, glutamate and glutamine concentrations in the anterior cingulate cortex (ACC), left insula, and visual cortex using 7T proton magnetic resonance spectroscopy (MRS). Glutathione and glutamate were significantly correlated in all three voxels. Glutamine concentrations across the three voxels were significantly correlated with each other. Principal components analysis (PCA) produced three clear components: an ACC glutathione–glutamate component; an insula-visual glutathione–glutamate component; and a glutamine component. Patients with stable schizophrenia had significantly lower scores on the ACC glutathione–glutamate component, an effect almost entirely leveraged by the sub-group of patients with residual schizophrenia. All three metabolite concentration values in the ACC were significantly reduced in this group. These findings are consistent with the hypothesis that excitotoxicity during the acute phase of illness leads to reduced glutathione and glutamate in the residual phase of the illness