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1. Transformer hot spot temperature estimation through adaptive neuro fuzzy inference system approach

Author

Edwell T. Mharakurwa and Dorothy W. Gicheru

Subjects
Hot spot temperature, Top oil temperature, Adaptive neuro-fuzzy inference system, Dynamic loading, Power transformer, Soft computing, Science (General), Q1-390, Social sciences (General), H1-99
Abstract

Transformer performance and efficiency can be enhanced by effectively address the properties of its insulation system. The power transformer insulation system weakens as a result of operational thermal stresses brought on by dynamic loading and shifting environmental patterns. Winding hot spot temperature is a crucial metric that must be maintained below the prescribed limit while power transformers are operating so as to maintained power system reliability. This is due to the fact that, among other variables, the time-dependent aging effect of insulation depends on transitions in hot spot temperatures. Due to the non‐linear nature of the conventional mathematical models used to determine these temperatures, and complexity of thermal phenomena, investigations still need to be exercised to fully understand the variables that associate with hot spot temperature computation with minimum error. This paper explores the possibilities of enhancing top oil and hot spot temperature estimation accuracy through the use of an adaptive neuro-fuzzy inference (ANFIS) technique. The paper presents an adaptive neuro fuzzy model to approximate the hot spot temperature of a mineral oil-filled power transformer based on loading, and established top oil temperature. Initially, a sub-ANFIS top oil temperature estimation model based on loading and ambient temperature as inputs is established. Using a hybrid optimization technique, the ANFIS membership functions were fine-tuned throughout the training process to reduce the difference between the actual and anticipated outcomes. The correctness and reliability of the created adaptive neural fuzzy model have been verified using real-world field data from a 60/90MVA, 132 kV power transformers under dynamic operating regimes. The ANFIS model results were validated against field measured values and literature-based electrical-thermal analogous models, establishing a precise input-output correlation. The developed ANFIS model achieves the highest coefficient of determination for both TOT and HST (0.98 and 0.96) and the lowest mean square error (7.8 and 10.3) among the compared thermal models. Correct determination of HST can help asset managers in thermal analysis trending of the in-service transformers, helping them to make proper loading recommendations for safeguarding the asset.

Published
2024
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2. Delays in hospital admissions in patients with fractures across 18 low-income and middle-income countries (INORMUS): a prospective observational study

Author

Panthea Pouramin, MSc, Chuan Silvia Li, MSc, Jason W Busse, PhD, Sheila Sprague, PhD, P J Devereaux, MD, Jagnoor Jagnoor, PhD, Rebecca Ivers, PhD, Mohit Bhandari, MD, Mohit Bhandari, PJ Devereaux, Gordon Guyatt, Brad Petrisor, Lehana Thabane, Respicious L. Boniface, Bruce Browner, Fernando de la Huerta, Rebecca Q Ivers, Theodore Miclau, III, Paul Moroz, Andrew Pollak, Gerard Slobogean, Parag Sancheti, Emil Schemitsch, Junlin Zhou, Sheila Sprague, Paula McKay, Chuan Silvia Li, Raman Mundi, Nathan O'Hara, Diane Heels-Ansdell, Lisa Buckingham, Nicole Simunovic, Jagnoor Jagnoor, Robyn Norton, Jing Zhang, Maoyi Tian, Soumyadeep Bhaumik, Samina Parveen, Saam Morshed, Madeline C. MacKechnie, Yang Liu, Yanrui Zhao, Junfei Li, Haoran Zhang, Zhentao Zhang, Wei Zhang, Tao Guo, Guang Chen, Zichao Jia, Jianzhong Yang, Lixing Kang, Peng Zhang, Haoqing Ma, Donghai Liu, Yinghua Ma, Yanguo Qin, Jincheng Wang, He Liu, Xinlong Ma, Jianxiong Ma, Haobo Jia, Shuangshuang Cui, Zhihu Zhao, Lin Fu, Hongqiang Jiang, Jianwei Lv, Sanbao Hu, Yongwei Wang, Mingyao Sun, Shuqing Tao, Baochang Qi, Ming Gao, Bo Wu, Chunsheng Zhi, Ben Xing, Jun Yang, Wenjie Dai, Duo Lu, Shisheng He, Xinyu Cai, Gejun Liu, Gang Rui, Baoshan Hu, Pingfang Shi, Hua Chen, Te Wang, Qingqing Wang, Linzhen Xie, Huanguang Xie, Tony Mutanda, Juliet Ntuulo, Flavia Lubega, Gayita Teddy Tracy, Kayondo Zaitun, Sylvester Ndayisaba, Titus Amone, Samuel Remmy Odong, Mark Lutomia, Caesar Okatch, Thomas Bitok, Alexander Kiambuthi, Fred Mathew Toboso Otsyeno, Pankaj G Jani, Vincent Muoki Mutiso, John EO Ating'a, Peter Kavoo Kilonzo, James Muoki, Makena Mbogori, Joan Wambui Wambugu, Dorothy Torutt, Christopher Odok, Elisha Ngetich, Dean Otsyeno, Juma Wakhayanga, Desmond Nzioka, Deogracia Owende, Ruth Lucinde, Brian Ngure Kariuki, Dennis Kinyua, Maureen Kamau, Maureen Mwancha, Mellany Murgor, Marilyn Nyabuti, Rita Njoki, Patricia Wanza, Abraham Odongo, Paul Marealle, Athman Wanini, Marwa Elisha, Damas Zumbulu, Pariyo Bonane Godfrey, Benjamin Mukulu Ndeleva, Murila Johnson, Moses Kimani, Kinuthia Gichui, Rogers Joachin Temu, Angela Neofitus Mselle, Ancelimu Rafael Kimario, Mmampapatla Thomas Ramokgopa, Gregory Firth, Anna Grisillo Biscardi, Machuene Ananias Poopedi, Johan Moolman, Brenda Milner, Matimba Maluleke, Maxwell Jingo, Susan van Deventer, Timothy Pikor, Ravi Bhaga, Michael Mara, Geoffrey Chege Mwangi, Anthony Muchiri Maina, David Wamae Gicheru, Carol Mwangi, Isaac Kingori Wangai, Peter Watson Maina, Ezra Mitei Kiptoo, Olufemi Olukemi Temiloluwa, Adeyeye Adeolu Ikechukwu, Ige Oluwole Olugbenga, Ojodu Ishaq Bamidele, Oladimeji Oladipupo Akanbi, Panchu Subramanian, Olivia L Mosweu, Samuel Hailu, Geletaw Tessema, Bahiru Bezabih, Birhanu Ayana, Hiwot Hailu, Betelhem Zewdneh, Hana Tesfaye, Sosena Tadesse, Dominic Konadu-Yeboah, Vincent Ativor, Peter Konadu, Dominic Awariyah, Raphael Quartey, Raphael Kumah-Ametepey, Osman Saani, Robert Ekow Quansah, Paa Kwesi Baidoo, Peter Trafton, David Anyitey-Korkor, Michael Leat, Johnny Sobotie, Godwin Opuni, Kwasi Kusi, Twimasi Baah, Paul Okyere, Bernice Mensah, Doris Akuoko Sarpong, Felicia Agbenorwu, Phyllis Osei-Donkor, Priscilla Opoku, Michael Segbefia, Gerald Chukwuemeka Oguzie, Emmanuel Chino Iyidobi, Cajetan Uwatoronye Nwadinigwe, Sharon Amarachi Uloma Oguzie, Emina Bami Kesiena, Henry Tanyi Ndasi, Nietiayurk Aminake Ghislain, Mala Irine Shey, Ikose John Nanje, Ashok Shyam, Madhav Borate, Sampat Dumbre Patil, Sachin Karkamakar, Shailesh Patil, Abhijeet Ranaware, Shadab Tamboli, Manish Gandhalikar, Rohini Tupe, Vishal Chaudhari, Avanti Joshi, Sanjay Patil, Mohit Madhukar Dalwekar, Tejas Gandhi, Chintamani Latkar, Gopal Pundkare, Sandeep Shrivastava, Pradeep K Singh, Sanjay Deshpande, Sumit Baheti, Ravi Mittal, Vijay Sharma, Vinoo Mathew Cherian, Thilak Samuel Jepegnanam, Vijay T K Titus, Manasseh Nithyananth, Palapattu R J V C Boopalan, Viju Daniel Varghese, Justin Arockiaraj, Anupam Mahajan, Bobby John, Ritesh Pandey, Jeewan S Prakash, Valsamma Abraham, Arti Rajkumar, Harvinder Singh Chhabra, Rajesh Sharawat, Ritabh Kumar, Pushkar Chawla, Rashmi Yadav, Rajagopalan N Iyer, Naveen Nair, Rajkumar S Amaravathi, Srinivasalu Santhanagopa, Anoop Pilar, Keith Behram Tamboowala, Mandeep S Dhillon, Sarvdeep S Dhatt, Asolie Chase, Neel M Bhavsar, Rameez Musa, Darshan Shah, Sunil Chodavadiyah, Pankaj G Patel, Raja Irfan Qadir, Syed Imran Bukhari, Khushnood Ali Baz, Subin Byanjankar, Ruban Raj Joshi, Rajeev Dwivedi, Jay Raj Sharma, La Ngoc Quang, Nguyen Duc Chinh, Vu Bao Hong, Paphon Sa-ngasoongsong, Noratep Kulachote, Norachart Sirisreetreerux, Wanjak Pongsamakthai, Irewin Alagar Tabu, Paula Veronica Reyes, Iardinne Caiquep, Joni Mitchell Robles Bituin, Jenna González, Mohammadreza Golbakhsh, Mashyaneh Haddadi, Soheil Saadat, Mohammadreza Zafarghandi, Clotilde Fuentes Orozco, José de Jesús Martínez Ruíz, Gustavo Armando Tafoya Arreguin, César Eduardo Pinedo Flores, Irydia Guadalupe Pellegrini Verduzco, Miguel Oscar Hernandez Camacho, Diego Abraham Estrada Téllez, Rodrigo Salcedo López, Ileana Guadalupe Canales Navarro, Mizael Dennis Pérez, Daniel de Jesús Enciso Carrillo, Paola Alejandra Álvarez López, Adán Cervantes Gómez, Fátima Nohemí Franco Bravo, Eugenia de los Ángeles Reyes Arias, Igor A. Escalante Elguezabal, Ennio Antonio Rizzo, Jean Michel Hovsepian, Victor Rodriguez, Manuel Malaret Baldo, Andres Serrano, Carlos G. Sanchez Valenciano, Edgar Efren Mercado Salcedo, Fryda Medina, Fernando Bidolegui, Sebastian Pereira, Gerardo Aguilar, Jorge Rubio-Avila, William Dias Belangero, José Ricardo Lenzi Mariolani, Bruno Livani, André Lugnani, Felipe Rossi, Angela Katayama, Fernando Baldy, Vinícius Ynoe de Moraes, Fabricio Fogagnolo, Kodi Edson Kojima, Jorge dos Santos Silva, Marco Kawamura Demange, Fernando Brandão de Andrade-Silva, Adriana Carvalho Gomes da Silva, Nelson Elias, Dino Aguilar Martinez, Fernando Contreras, Mario Garuz, Jose Eduardo Quintero, Gavino Merchan, Christian M. Lozano Lurita, Aturo D. Torres Manrique, Jorge Hurtado Fernandez, Sergio Iriarte Vincenti, Alfredo Pozzo Bobarin, Dalton Salinas Sanchez, Julio Segovia Altieri, Diego Almada, Derlis Bogado, Carlos Coronel, Cristian Boveda, Victor del Valle, Carlos Montiel, Nelson Marin, Antonio Barquet, Daniel Rienzi, Carlos Amanquez, Georges Beauvoir, Iván J Salce Cutipa, José Eduardo Grandi Ribeiro, José María Jiménez Avila, Luis Padilla, Hernando Cuevas Ochoa, Hernando Cuevas Cano, Adriana Vaca González, Nubia Itzel Gonzalez Gutierrez, and Victor Espinola

Subjects
Public aspects of medicine, RA1-1270
Abstract

Summary: Background: The Lancet Commission on Global Surgery established the Three Delays framework, categorising delays in accessing timely surgical care into delays in seeking care (First Delay), reaching care (Second Delay), and receiving care (Third Delay). Globally, knowledge gaps regarding delays for fracture care, and the lack of large prospective studies informed the rationale for our international observational study. We investigated delays in hospital admission as a surrogate for accessing timely fracture care and explored factors associated with delayed hospital admission. Methods: In this prospective observational substudy of the ongoing International Orthopaedic Multicenter Study in Fracture Care (INORMUS), we enrolled patients with fracture across 49 hospitals in 18 low-income and middle-income countries, categorised into the regions of China, Africa, India, south and east Asia, and Latin America. Eligible patients were aged 18 years or older and had been admitted to a hospital within 3 months of sustaining an orthopaedic trauma. We collected demographic injury data and time to hospital admission. Our primary outcome was the number of patients with open and closed fractures who were delayed in their admission to a treating hospital. Delays for patients with open fractures were defined as being more than 2 h from the time of injury (in accordance with the Lancet Commission on Global Surgery) and for those with closed fractures as being a delay of more than 24 h. Secondary outcomes were reasons for delay for all patients with either open or closed fractures who were delayed for more than 24 h. We did logistic regression analyses to identify risk factors of delays of more than 2 h in patients with open fractures and delays of more than 24 h in patients with closed fractures. Logistic regressions were adjusted for region, age, employment, urban living, health insurance, interfacility referral, method of transportation, number of fractures, mechanism of injury, and fracture location. We further calculated adjusted relative risk (RR) from adjusted odds ratios, adjusted for the same variables. This study was registered with ClinicalTrials.gov, NCT02150980, and is ongoing. Findings: Between April 3, 2014, and May 10, 2019, we enrolled 31 255 patients with fractures, with a median age of 45 years (IQR 31–62), of whom 19 937 (63·8%) were men, and 14 524 (46·5%) had lower limb fractures, making them the most common fractures. Of 5256 patients with open fractures, 3778 (71·9%) were not admitted to hospital within 2 h. Of 25 999 patients with closed fractures, 7141 (27·5%) were delayed by more than 24 h. Of all regions, Latin America had the greatest proportions of patients with delays (173 [88·7%] of 195 patients with open fractures; 426 [44·7%] of 952 with closed fractures). Among patients delayed by more than 24 h, the most common reason for delays were interfacility referrals (3755 [47·7%] of 7875) and Third Delays (cumulatively interfacility referral and delay in emergency department: 3974 [50·5%]), while Second Delays (delays in reaching care) were the least common (423 [5·4%]). Compared with other methods of transportation (eg, walking, rickshaw), ambulances led to delay in transporting patients with open fractures to a treating hospital (adjusted RR 0·66, 99% CI 0·46–0·93). Compared with patients with closed lower limb fractures, patients with closed spine (adjusted RR 2·47, 99% CI 2·17–2·81) and pelvic (1·35, 1·10–1·66) fractures were most likely to have delays of more than 24 h before admission to hospital. Interpretation: In low-income and middle-income countries, timely hospital admission remains largely inaccessible, especially among patients with open fractures. Reducing hospital-based delays in receiving care, and, in particular, improving interfacility referral systems are the most substantial tools for reducing delays in admissions to hospital. Funding: National Health and Medical Research Council of Australia, Canadian Institutes of Health Research, McMaster Surgical Associates, and Hamilton Health Sciences.

Published
2020
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