scholarly journals Enhancing Service Life of Power Transformer through Inhibiting the Degradation of Insulating oil by New Approach

2020 ◽  
Vol 7 (10) ◽  
pp. 369-374
Author(s):  
Yasir Khan ◽  
◽  
Muhammad Iftikhar Khan ◽  

Oil reclamation is a transformer insulation reconditioning technique which may be used as on-line or off-line. However, there is a need of evidence showing the effect of this process on conditions of the paper insulation, which indeed affects the life span of a transformer. This research work focuses on oil reclamation experiment on an old retired distribution transformer. Electrical testing and post-mortem analysis of the transformer were conducted, aimed at investigating the design aspects and collecting information on the insulation conditions prior to the oil reclamation. Temperature and moisture sensors were installed to monitor the conditions within the transformer during the oil reclamation [2]. The experimental process of transformer Oil reclamation was performed into two phases, with regular oil sampling to analyze the changes in key oil parameters, namely acidity number (AN), moisture and breakdown voltage (BV). This was accompanied by paper sampling at the end of each reclamation cycle to study the effects of oil reclamation on properties, particularly moisture, LMA and degree of polymerization. The transformer which was used for the entire experimental process was about 45 years old, 200kVA, 1100 / 415-240V distribution transformer. In order to study the long-term effect of oil reclamation, oil samples were collected from an on-site reclamation exercise performed in a laboratory-accelerated thermal ageing experiment. Oil samples collected before and after the reclamation were aged alongside new oils for comparison [4]. Through the regular monitoring and measurement of oil parameters (AN, moisture and BD strength) over 144 hours and paper parameters (LMA, moisture and DP) at specific stages of phase 1, it was observed that the transformer oil-paper insulation system was significantly improved. The entire research work was performed into two phases (phase 1 and phase 2). The “phase 1” was aimed to improve and restore the oil parameters comparable to the parameters of new oil as specified in “IEC-60296” and its effect on the paper insulation. “Phase 2” was aimed to compare the life span of reclaimed oil filled transformer with the transformer in which aged oil has been replaced by new oil[6]. Effective study of oil reclamation was analyzed through laboratory accelerated aging experiment and real time application on a 45 years old transformer. Through the regular monitoring and measurement of oil parameters (AN, moisture and BD strength) over 144 hours and paper parameters (LMA, moisture and DP) at specific stages of phase1, it was observed that the transformer oil-paper insulation system was significantly improved [15].

Author(s):  
Srinivasan Sridhar ◽  
Nazmul Kazi ◽  
Indika Kahanda ◽  
Bernadette McCrory

Background: The demand for psychiatry is increasing each year. Limited research has been performed to improve psychiatrist work experience and reduce daily workload using computational methods. There is currently no validated tool or procedure for the mental health transcript annotation process for generating “gold-standard” data. The purpose of this paper was to determine the annotation process for mental health transcripts and how it can be improved to acquire more reliable results considering human factors elements. Method: Three expert clinicians were recruited in this study to evaluate the transcripts. The clinicians were asked to fully annotate two transcripts. An additional five subjects were recruited randomly (aged between 20-40) for this pilot study, which was divided into two phases, phase 1 (annotation without training) and phase 2 (annotation with training) of five transcripts. Kappa statistics were used to measure the inter-rater reliability and accuracy between subjects. Results: The inter-rater reliability between expert clinicians for two transcripts were 0.26 (CI 0.19 to 0.33) and 0.49 (CI 0.42 to 0.57), respectively. In the pilot testing phases, the mean inter-rater reliability between subjects was higher in phase 2 with training transcript (k= 0.35 (CI 0.052 to 0.625)) than in phase 1 without training transcript (k= 0.29 (CI 0.128 to 0.451)). After training, the accuracy percentage among subjects was significantly higher in transcript A (p=0.04) than transcript B (p=0.10). Conclusion: This study focused on understanding the annotation process for mental health transcripts, which will be applied in training machine learning models. Through this exploratory study, the research found appropriate categorical labels that should be included for transcripts annotation, and the importance of training the subjects. Contributions of this case study will help the psychiatric clinicians and researchers in implementing the recommended data collection process to develop a more accurate artificial intelligence model for fully- or semi-automated transcript annotation.


Author(s):  
Ariela Araujo Fonseca ◽  
Yovanka Pérez Ginoris ◽  
Norma Mendes Pinheiro Gontijo ◽  
Marco Antonio Almeida de Souza

Biological processes are the most widespread methods for wastewater treatment. However, they are limited in their ability to degrade toxic and refractory pollutants, contaminants that electrochemical processes can remove. Therefore, this research explored the possibility of treating sewage by an anaerobic biological process followed by an aerobic system integrated to an electrolytic process. Three sequential batch reactors were operated in an automated way. Each of three reactors represented a process: aerobic biological treatment (BR); electrolytic treatment (ER); and a combination of both, the bio electrolytic reactor (BER). Two phases were ran with different electrodes: (Phase 1) stainless steel and (Phase 2) graphite. The electric current was varied from 0.001 to 0.100 A. COD, TS, SS, turbidity, and the zooplankton community were monitored. The highest organic matter removal efficiencies were 86%, 79% and 87% for BR, ER and BER, respectively. The best weekly BER efficiencies for COD removal were 90% and 98%, with current densities of 0.27 A/m2 (Phase 1) and 0.05 A/m2 (Phase 2). The main conclusions about bio electrolytic process were: (1) it did not achieve organic matter removal high enough to justify its application; (2) inert electrodes are the more indicated; and (3) the zooplankton community was affected by the electric current.


2021 ◽  
Author(s):  
Christina Mutschler ◽  
Jen Rouse ◽  
Kelly McShane ◽  
Criss Habal-Brosek

Background Psychosocial rehabilitation is a service that supports recovery from mental illness by providing opportunities for skill development, self-determination, and social interaction. One type of psychosocial rehabilitation is the Clubhouse model. The purpose of the current project was to create, test, and refine a realist theory of psychosocial rehabilitation at Progress Place, an accredited Clubhouse. Method Realist evaluation is a theory driven evaluation that uncovers contexts, mechanisms, and outcomes, in order to develop a theory as to how a program works. The current study involved two phases, encompassing four steps: Phase 1 included (1) initial theory development and (2) initial theory refinement; and Phase 2 included (3) theory testing and (4) refinement. Results The data from this two-phase approach identified three demi-regularities of recovery comprised of specific mechanisms and outcomes: the Restorative demi-regularity, the Reaffirming demi-regularity, and the Re-engaging demi-regularity. The theory derived from these demi-regularities suggests that there are various mechanisms that produce outcomes of recovery from the psychosocial rehabilitation perspective, and as such, it is necessary that programs promote a multifaceted, holistic perspective on recovery. Conclusions The realist evaluation identified that Progress Place promotes recovery for members. Additional research on the Clubhouse model should be conducted to further validate that the model initiates change and promotes recovery outcomes.


2018 ◽  
Vol 7 (4) ◽  
pp. 227-237 ◽  
Author(s):  
Karolyn Vaughan ◽  
Anne McMurray ◽  
Mary Sidebotham ◽  
Jennifer Gamble

Background:Certification as a lactation consultant is based on practitioners having achieved a standard of knowledge indicative of their competence to practice by passing a psychometric examination. The underpinning principle of recertification programs is to support clinicians to become lifelong learners by progressively enhancing and advancing their knowledge and skills in line with contemporary evidence. The aim of this study was to investigate the factors that influence International Board Certified Lactation Consultants (IBCLCs) to advance their practice.Method:A mixed-methods study was conducted in two phases. Phase 1 included focus groups, interviews, and participants’ demographic data. Phase 2 comprised of an online questionnaire to IBCLCs. This approach was designed to provide a comprehensive qualitative understanding of the IBCLCs’ experiences, which was then triangulated with quantitative data from a significantly larger population of IBCLCs in Phase 2.Results:The findings are described in themes and subthemes. Participants in phase 2 (n = 3,946) reported being intrinsically motivated (93.3%, n = 3,631) and committed to providing evidence-based guidance and optimal care to support breastfeeding mothers. They identified various sources of continuing education, although attendance at conferences, peer support, and reflective sessions were the most common approaches to enhancing knowledge. They recognized that it was through extension of knowledge that they were able to advance their practice.Conclusion:This article identifies strategies that the managers, educators, and certification bodies can adopt to support the IBCLCs in continuing to advance their practice, which will ultimately improve breastfeeding outcomes for mothers.


2017 ◽  
Vol 76 (1) ◽  
Author(s):  
Ving F. Chan ◽  
Hasan Minto ◽  
Eden Mashayo ◽  
Kovin S. Naidoo

Purpose: Vision Champions (VC) are children trained to perform simple eye health screening and share eye health messages among their community. Our objectives were to assess the ability of VC in identifying and referring children and the community with refractive error and obvious ocular disease and to assess the change in knowledge and practice of eye healthseeking behaviour of the community 3 months after the introduction of the Vision Champion Programme.Methods: We purposively sampled 600 households and interviewed 1051 participants in two phases with a close-ended questionnaire. The numbers of children screened, referred by the VC and those who attended the Vision Centre were recorded. The percentage of people who answered the questions correctly were compared between Phase 1 (P1) and Phase 2 (P2).Results: The VC shared their eye health messages with 6311 people, screened 7575 people’s vision and referred 2433 people for further care. The community were more aware that using eye ointment not prescribed by doctors (P1 = 58.96% vs. P2 = 72.75%) can lead to blindness. Participants were more aware that they should not administer eye drops in stock (P1 = 44.18% vs. P2 = 61.37%) or received from a friend or relative (P1 = 53.23% vs. P2 = 72.35%) if their eyes are red and painful.Conclusion: Children have the potential to effectively share eye health messages and conduct simple vision screening for their families and peers. Efforts are needed to sensitise the community to improve the referral or follow-up rate.


2017 ◽  
Vol 2630 (1) ◽  
pp. 134-146 ◽  
Author(s):  
Braden T. Smith ◽  
Robert A. Moore ◽  
Isaac L. Howard

This paper presents a discussion with data on factors related to the in-place density measurement of asphalt pavements. A review of the literature traces changes to asphalt density measurement technologies over the past 60 years. Two phases of investigation then are presented in which in-place density was evaluated for an ongoing study of environmental effects at a test section in Columbus, Mississippi. A series of laboratory and field activities was performed in Phase 1. In Phase 2, studies were made of laboratory drying practices of specimens that were cored after an extended period of field aging. The key conclusion from these efforts was that ASTM D7227 might not remove sufficient moisture from some specimens to achieve accurate density measurement when pavements have been exposed to moisture for extended periods of time. This paper presents a case with an average error in air void measurement of 0.9% (measured 9.1% when 10% was correct) for specimens that were cored, dried according to ASTM D7227, and then measured for mass in air 1 day later. This finding is of most concern to rehabilitation and research work in areas in which aggregates have high potential for absorption but is of no concern to new construction projects. Furthermore, the work presented here validated the use of ASTM D7227 in circumstances in which mixtures were exposed to moisture for short periods of time. The work also suggested three options to take to accurately measure in-place density for performance testing of aged pavements that contain high-absorption aggregates (i.e., dry in oven, develop correlation equations, or dry for several weeks).


2020 ◽  
pp. 112067212093059 ◽  
Author(s):  
Barbara Parolini ◽  
Michele Palmieri ◽  
Alessandro Finzi ◽  
Gianluca Besozzi ◽  
Angela Lucente ◽  
...  

Purpose: To describe a comprehensive OCT-based classification of myopic traction maculopathy (MTM). Methods: Two hundred eighty-one eyes with MTM (visited from 2006 to 2018), were retrospectively reviewed for age, best-corrected-visual-acuity (BCVA), axial length (AL), optical coherence tomography (OCT), and wide-field color fundus-photographs. The study was divided in two Phases. Phase 1: MTM types were categorized with OCT and correlated with age and BCVA. The type of staphyloma was described. Phase 2: the evolution of MTM was studied evaluating at least three OCT exams of each eye taken at different timings (interval between each exam: 1–10 years). Results: Phase 1: We identified, four MTM retinal stages (1. Inner/Outer Maculoschisis; 2. Predominantly outer Maculoschisis; 3. Maculoschisis-Macular Detachment; 4. Macular Detachment) and three foveal stages (a. Normal fovea; b. Inner Lamellar-Macular-Hole; c. Full-Thickness-Macular-Hole). Outer-Lamellar-Macular-Holes and epiretinal abnormalities were associated findings. Stages 1 to 2 were younger than stages 3 to 4 ( p < 0.05). BCVA in stages 1, 2 was similar, and higher than stages 3, 4 ( p < 0.02). About 14% of eyes had no staphyloma, 73% of eyes had staphyloma type 1 or 2. MTM stages were not correlated with AL. Phase 2: The retina could change in time from stage 1 to 4, or the fovea could change from stage a to c. Mean evolution time from stage 1 to 2, stage 2 to 3, and 3 to 4 were 20, 12, 3 months, respectively. BCVA decreased over time as stages increased ( p = 0.47). Conclusion: The MSS Table displays a new classification, the natural evolution, and practical insights for the management of MTM.


1989 ◽  
Vol 66 (1) ◽  
pp. 210-216
Author(s):  
J. D. Cornish ◽  
D. R. Gerstmann ◽  
D. M. Null ◽  
M. D. Smith ◽  
T. J. Kuehl

Minimum acceptable O2 delivery (DO2) during extracorporeal membrane oxygenation (ECMO) remains to be defined in a newborn primate model. The right atrium, carotid artery, and femoral artery were cannulated, and the ductus arteriosus, aorta, and pulmonary artery ligated in neonatal baboons (Papio cynocephalus) under a combination of ketamine, diazepam, and pancuronium. The internal jugular vein was also cannulated retrograde to the level of the occipital ridge. We measured hemoglobin, pH, arterial and venous PO2 (both from the pump circuit and from the cerebral venous site), serum lactate and bicarbonate concentrations, and pump flow, and we calculated hemoglobin saturations, (DO2), O2 consumption (VO2), systemic O2 extraction, and cerebral O2 extraction. Six baboons were studied during each of two phases of the experiment. In the first, flow rates were varied sequentially from 200 to 50 ml.kg-1.min-1 with saturation maximized. In the second, flow was maintained at 200 ml.kg-1.min-1 and saturation was reduced sequentially from 100 to 38%. VO2 fell significantly below baseline at a flow rate of 50 ml.kg-1.min-1 and a DO2 of 8 +/- 2 (SE) ml.kg-1.min-1 in phase 1 and at DO2 of 12 +/- 5 in phase 2. Both systemic and cerebral O2 extraction rose significantly at a flow of 100 ml.kg-1.min-1 and DO2 of 17 +/- 4 ml.kg-1.min-1 in phase 1, whereas neither rose with decreasing DO2 in phase 2. In fact, cerebral extraction fell significantly DO2 of 16 +/- 6 ml.kg-1.min-1.(ABSTRACT TRUNCATED AT 250 WORDS)


2020 ◽  
Vol 44 (1) ◽  
pp. 157-170
Author(s):  
Mugdha Sharma ◽  
Laxmi Ahuja ◽  
Vinay Kumar

The proposed research work is an effort to provide accurate movie recommendations to a group of users with the help of a rule-based content-based group recommender system. The whole approach is categorized into 2 phases. In phase 1, a rule- based approach has been proposed which considers the users’ viewing history to provide the Rule Base for every individual user. In phase 2, a novel group recommendation system has been proposed which considers the ratings of the movies as per the rule base generated in phase 1. Phase 2 also considers the weightage of every individual member of the group to provide the accurate movie recommendation to that particular group of users. The results of experimental setup also establish the fact that the proposed system provides more accurate outcomes in terms of precision and recall over other rule learning algorithms such as C4.5.


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