AUTOR DO BLOG ENG.ARMANDO CAVERO MIRANDA SÃO PAULO BRASIL

"OBRIGADO DEUS PELA VIDA,PELA MINHA FAMILIA,PELO TRABALHO,PELO PÃO DE CADA DIA,PROTEGENOS DO MAL"

"OBRIGADO DEUS PELA VIDA,PELA MINHA FAMILIA,PELO TRABALHO,PELO PÃO DE CADA DIA,PROTEGENOS  DO MAL"

“SE SEUS PROJETOS FOREM PARA UM ANO,SEMEIE O GRÂO.SE FOREM PARA DEZ ANOS,PLANTE UMA ÁRVORE.SE FOREM PARA CEM ANOS,EDUQUE O POVO.”

“Sixty years ago I knew everything; now I know nothing; education is a progressive discovery of our own ignorance. Will Durant”

domingo, 17 de março de 2024

7º Congresso Brasileiro de Eletrônica de Potência - COBEP2003


 Sempre apoiando  a PESQUISA E DESENVOLVIMENTO no BRASIL durante toda minha vida me dediquei a minha paixão a Eletrônica de Potência ,hoje temos muitos Doutores e Mestres em todas as universidades e setores da industria nacional,no novo escenario mundial e muito importante o conhecimento sempre de novas tecnologias.

quinta-feira, 14 de março de 2024

MOURA uma empresa que enorgulhece o Brasil, com 66 anos de historia lider do setor de baterias AUTOMOTIVAS,INDUSTRIAIS,ESTACIONARIAS,SOLAR

 

https://picasion.com/
https://picasion.com/

Tive a satisfação de visitar a Empresa Moura genuinamente Brasileira junto com meus colegas peruanos Sr. Rodolfo Araujo Diretor da empresa peruana INTERSAC junto com seu filho Edson Araujo e o Sr. Cesar Quintero Gerente de Moura na Colombia,devo expresar meu agradecimento especial a Srta.Debora Daiana Silva Gerente Comercial LATAM | Gestão de Contas | Abertura de Mercado | Expansão de Negócios | Planejamento Estratégico | Liderança e Formação de Equipes,realmente o que mais me impresionou foi sua organização,seu Instituto de Pesquisa e Desenvolvimento,seu proceso de produção e Controle de Qualidade,devo resaltar seu Programa Social com Instituto Moura de Formação Tecnica de jovem talentos de jovens da comunidade da Cidade Bela Jardim,tem cursos de Robótica,Matemáticas,Ciências de \Computação e aulas de musica,e um Cinema,todos estes serviços são totalmente gratuitos, alem de isso continuan expandiendo seus investimentos no desenvolvimento de novas aplicações no setor de energia como os automoveis elétricos,desejo que o sucesso continue.
Muito Obrigado Moura.

sábado, 9 de março de 2024

리튬 배터리의 화재 및 폭발 위험성에 관한 연구 A Study on the Explosion and Fire Risk of the Lithium Battery-Author Sang-Bo Sim- Hoseo University



리튬 배터리의 화재 및 폭발 위험성에 관한 연구 A Study on the Explosion and Fire Risk of the Lithium Battery-Author Sang-Bo Sim- Hoseo University

ABSTRACT 

Due to recent development of IT technology, information level of Korea is said to be the world-best. Thus mobile devices such as cell phones, notebook, and tablet PC that could be used without limitations are trending. Along the trend, high energy high density secondary batteries used as the power source for portable devices are also in the spotlight, and among them Lithium battery demand is rising. Generally a Lithium battery should be certified with KS C 8541 (Lithium secondary battery rule) in order to be on the market. However, battery accidents are growing in number and people are raising questions about the safety of the batteries. Certified Lithium battery’s safety is guaranteed within normal state, but at abnormal states such as damage to protective circuit, the danger rises due to elimination of minimum protection. Recent studies regarding Lithium batteries only measured ignition status for flammable gas, but did not provide detailed analysis. Also, risk analysis according to battery capacity and comparative analysis between the two representative batteries, Lithium Polymer battery and Lithium Ion battery are rarely carried out. Also, research about general danger of Lithium batteries such as ignition at high temperature environment is incomplete. This study selected five types of Li-Polymer batteries and three types of Li-Ion batteries of different capacity in order to analyze ignition and fire danger according to usage environment. The results are as following. 1. We designed an ignition circuit using IEC type spark ignition test apparatus based on KS C IEC 60079-11 standard in order to measure the explosion hazard of Lithium battery spark discharge. Through measuring the ignition limit of methane, propane, ethylene, and helium, the result showed that gas with higher danger showed more explosion to less number of battery connection. Also, batteries with not Protection Circuit Module (PCM) exploded more often during connection with battery compared with batteries that had protection circuits. 2. An experiment was conduction using a pyrostat based on UL 1642 and KS C 8541 standard in order to measure Lithium battery’s explosion danger at high temperature environment. As the result, Li-Polymer batter with pack type external material had higher risk of explosion compared to cap type Li-Ion battery. Li-Polymer battery had 160~170℃ explosion between 1970~2700 seconds, and the explosion occurred for the electrolytes seeped out from the cracked battery pack after swelling due to evaporation. On the other hand, Li-Ion battery had 176~197℃ explosion between 3000~3800 seconds caused by vaporized electrolyte increasing the pressure within the battery and protruding to the vulnerable positive (+) end. 3. Short circuit was designed in order to measure the temperature increase according to the short circuit current. For batteries with protection circuit, there was no temperature change caused by short circuit current due to current limitation. However, for batteries with no protection circuit, 30.7~35.6A of maximum short circuit current was produced. For Li-Polymer battery, the current fell until 3.9~12.7A after the maximum short circuit current, but increased again to 5.5~17.8A, showing two-step curve pattern. The maximum temperature was 125℃. For Li-Ion battery, the maximum short circuit current fell steeply to 1.3A and decreased steadily, showing a single step curve pattern. It is because the PTC thermistor embed inside limited the flowing current. The maximum temperature was 95℃. Thus in order to minimize the danger of Lithium battery explosion, the Lithium battery connection number and discharge characteristics should be considered when used at environment with flammable gas. And swelling and explosive characteristics should be considered when using Li-Polymer and Li-Ion batteries at high temperature environment. Also, to prevent hazards caused by mistakes and abnormal statues, a dual safety device of protection circuits are recommended.

sexta-feira, 8 de março de 2024

Задачник по физике. Чертов А.Г., Воробьев А.А. -Problem in physics. Chertov A.G., Vorobiev A.A. -


 







-Problem in physics. Chertov A.G., Vorobiev A.A. 

 The problem book was compiled in accordance with the current syllabus for the physics course for college students. Each section includes a sufficient number of tasks, the difficulty of which increases with increasing serial number. At the beginning of each paragraph, basic laws and formulas are given, and examples of solving typical problems are given. At the end of the book, answers to all problems are given. The 7th edition (6th - 1997) includes more than 150 new problems and examples, the theoretical part of each section has been significantly expanded, and the necessary corrections have been made. For students of higher technical educational institutions.


VIEW FULL TEXT HERE:

https://drive.google.com/file/d/1lbWLmycZjLjj9uSJmuXtZUTgIho3hCJK/view?usp=sharing

Collected Papers Of P. L. Kapitza -PRIMER VOLUME-TOMO i


 

Collected Papers of P. L. Kapitza, Volume I 

Compiles the scientific papers written between 1916 and 1934 by Piotr Leonidovich Kapitza, a leading Soviet physicist and Nobel laureate. This book begins by introducing the life and career of P. L. Kapitza, which includes his studies and investigations of nuclear physics, strong magnetic fields, liquefaction, liquid helium, and high-power electronics. Other topics discussed include electron inertia in molecular ampere currents; Koch recording microphotometer; metallic conductivity and its change in a magnetic field; and methods of experimenting in strong magnetic fields. The liquefaction of helium by an adiabatic method; Zeeman and Paschen-Back effects in strong magnetic fields; and theoretical and empirical expressions for the heat transfer are also emphasized in this text. This compilation is a good reference for students and researchers conducting work on the biography and scientific contributions of P. L. Kapitza. 

 Volume 1 here: