Foram encontradas 51 questões.
A corrosão, em especial a eletroquímica, é um processo que, inquestionavelmente, está presente direta ou indiretamente no nosso cotidiano. Ela ocorre não só no ambiente doméstico, mas, também, nos ambientes urbanos, como: pontes e seus pilares, monumentos, equipamentos e objetos metálicos, e até mesmo em processos que ocorrem no ambiente industrial. Nesse sentido, a natureza eletroquímica da corrosão metálica se faz presente na corrosão microbiana, em que os microrganismos participam de forma ativa no processo, mas sem modificar as características da reação eletroquímica.
As bactérias redutoras de sulfato (BRS) têm grande importância na biocorrosão. Embora, até o momento não exista a determinação de um mecanismo único de corrosão ocasionado pela ação das BRS, Kuhr e Vlug (1934) propuseram um mecanismo no qual essas bactérias utilizam o hidrogênio proveniente do consumo realizado pela hidrogenase, catalisando a ativação reversível de hidrogênio. Em condições anaeróbicas, essa reação de corrosão é a evolução de hidrogênio pela dissociação da água, em que os íons de hidrogênio produzidos se encontram adsorvidos sobre a superfície metálica, sendo posteriormente consumidos pelo processo metabólico, como mostra a figura abaixo:
De acordo com o que mostra a figura e a descrição do mecanismo de corrosão supracitado, esse tipo de biocorrosão é classificado como
Provas
Os principais microrganismos causadores da biocorrosão são bactérias presentes no ciclo natural do enxofre. No entanto, outros microrganismos, também estão associados à esse processo. Com isso, dentre as alternativas abaixo, assinale aquela que apresenta a informação errada acerca do microorganismo ou da sua ação, enquanto agente promotor do biofouling ou causador da biocorrosão.
Provas
A biocorrosão e o biofouling das superfícies metálicas têm origens em processos biológicos que ocorrem pela participação de microrganismos aderidos às superfícies, formando biofilmes na interfase metal/solução. A biocorrosão manifesta-se em diferentes condições, porém ela ocorre com maior frequência em meio aquoso. Nesse sentido, considerando as etapas e os microrganismos envolvidos na formação de um biofilme, classifique as afirmativas abaixo em verdadeira (V) ou falsa (F).
( ) | As bactérias planctônicas formam um biofilme através da síntese de exopolímeros, em geral, polissacarídeos que passam a envolver e aglutinar as células, protegendo-as das condições adversas ao meio ambiente, como a ação dos biocidas. |
( ) | Após a etapa de fixação e, havendo nutrientes suficientes, as bactérias se multiplicam, o biofilme aumenta o seu volume e outros organismos, como: fungos e algas, podem aderir à estrutura do biofilme. |
( ) | O biofilme faz parte, também, do chamado biofouling, que se refere ao acúmulo indesejável de depósitos biológicos sobre uma superfície. |
( ) | Dentre os principais microrganismos associados à biocorrosão, estão as bactérias redutoras de sulfato e oxidantes de enxofre, bactérias oxidantes de ferroe manganês, e bactérias formadoras de limos. No entanto, com menor frequência, mas importantes, são alguns eucariotos, como fungos e algas que, também, estão associados à biocorrosão. |
As afirmativas são, respectivamente,
Provas
Em sistemas em que os materiais metálicos estão imersos, há uma aceleração do seu processo corrosivo que impacta, de forma significativa, sua utilização, custo e mesmo problemas ambientais, estruturais e de saúde pública. Além dos processos físico-químicos que facilitam e aceleram o processo corrosivo, ocorre, também, a corrosão induzida por grupos de microrganismos, a biocorrosão. A proliferação microbiana, em geral, de grupos de bactérias na superfície desses materiais, seguida da formação de comunidades imersas em uma matriz de polissacarídeo extracelular, aumenta a aderência e dificulta a remoção desses microrganismos das superfícies as quais estão acoplados, propiciando, assim, a multiplicação celular e, consequentemente, uma maior área afetada nos materiais. A figura a seguir mostra os fatores determinantes da adesão bacteriana que constituem a tríade interação: microrganismo, ambiente e material que ocorre durante a biocorrosão.
Considerando o que mostra a figura e os fenômenos que ocorrem durante a biocorrosão, analise as afirmativas abaixo:
I. A biocorrosão pode ocorrer pela degradação de resinas utilizadas no revestimento de materiais metálicos, produção de H₂S e pela excreção de metabólitos que acidificam o meio em que estão inseridos. Este processo é capaz de alterar o produto final, modificando sua estrutura e propiciando a formação de outros compostos ou ocasionando danos estruturais permanentes.
II. As resinas são formadas por compostos exclusivamente orgânicos e, por isso, podem ser utilizadas pelos microrganismos como fonte de nutriente. Desta forma, ao utilizar desta matriz para nutrição, e consequente excreção de metabólitos, esta camada protetora do material metálico vai se enfraquecendo, favorecendo o processo corrosivo pelo próprio microrganismo, como por outros fatores do meio em que estão inseridos.
III. As bactérias redutoras de sulfato (BRS), atuam como agente oxidante para aproveitamento da matéria orgânica e, consequente, absorção de enxofre. Porém, durante este processo, parte desse composto é liberado para o meio na forma de H₂S, favorecendo a corrosão. Essas bactérias possuem a característica de, normalmente. causar uma corrosão puntiforme ou pite, onde a sua profundidade é maior do que seu diâmetro.
Assinale
Provas
A degradação de materiais é um processo que leva a perdas financeiras em diversos segmentos industriais pela falha prematura de seus componentes. Uma das causas para tal problema é a corrosão microbiológica. Diferentes mecanismos podem agir, de maneira individual ou em conjunto, para promover essa degradação, com destaque para: formação de biofilme, redução de íons sulfato e variação do pH em áreas localizadas de um sistema. Considerando os mecanismos que levam à biocorrosão, assinale a afirmativa incorreta.
Provas
Choose the best alternative: “Brazilians’ sense of belief in institutions .”
Provas
Choose the best alternative: “People have changed to virtual political protests, ?”
Provas
Leia atentamente o texto a seguir e responda às questões de 17 a 24.
04.08.2024
‘We have reached the limit.’ Clash with Elon Musk prompts calls for social media controls in Brazil
London (CNN) — Brazil’s attorney general has called for social media platforms in the country to be regulated after Elon Musk threatened to disobey a court order banning certain accounts on X and lashed out against “aggressive censorship.”
In a post on X Sunday, Attorney General Jorge Messias wrote: “It is urgent to regulate social networks. We cannot live in a society in which billionaires domiciled abroad have control of social networks and put themselves in a position to violate the rule of law, failing to comply with court orders and threatening our authorities.”
In a statement, Brazil’s Supreme Court described Musk’s defiance as a “flagrant” obstruction of justice and said he should be investigated by the police. Supreme Court Justice Alexandre de Moraes announced Sunday that he would open an inquiry into the billionaire businessman who owns X.
The standoff is the latest clash between authorities around the world and Musk – a self-declared “free speech absolutist” who has relaxed X’s content moderation policies and reinstated a number of previously blocked accounts after buying the company, formerly known as Twitter, in 2022.
Orlando Silva, a Brazilian lawmaker aligned with the country’s left-wing government, said he would propose a “responsibilities regime for these digital platforms.” “We have reached the limit!” he posted on X, adding that Musk had disrespected the judiciary.
On Saturday, X’s global government affairs team posted that it had been “forced by court decisions to block certain popular accounts in Brazil” and threatened with “daily fines” for non-compliance.
“We do not know which posts are alleged to violate the law. We are prohibited from saying which court or judge issued the order, or on what grounds,” they wrote. They do not believe the orders are constitutional and will challenge them legally where possible, they added.
The Supreme Court had ordered that the accounts be blocked as part of its ongoing investigation into “digital militias,” which, among other things, is looking into the spread of misinformation and incitement of crime under the government of former far-right President Jair Bolsonaro.
Social media platforms have been widely viewed as a catalyst for riots in Brazil that took place on January 8 last year, when hundreds of protesters broke into federal government buildings in the capital Brasilia, in scenes reminiscent of the January 6, 2021, insurrection in the United States.
Musk suggested that Moraes was behind the ban, writing Sunday on X that the judge had “brazenly and repeatedly betrayed the constitution and people of Brazil. He should resign or be impeached.”
In a separate post Saturday, he called the court’s decision to block the accounts “aggressive censorship” that “appears to violate the law and will of the people of Brazil.” He said X would defy the court’s order and lift all restrictions.
“As a result, we will probably lose all revenue in Brazil and have to shut down our office there. But principles matter more than profit,” he noted.
X has faced criticism for accommodating government censorship demands in the past, with Musk saying the company has no choice but to comply. For example, it blocked some X accounts in Turkey at the behest of the government ahead of the country’s elections last year, while at the same time contesting the orders in court.
(Internet: <https://edition.cnn.com/2024/04/08/tech/elon-musk-brazil-investigation/index.html> )
In “As a result, we will probably lose all revenue in Brazil and have to shut down our office there. But principles matter more than profit”, it is not possible to say that Musk
Provas
Leia atentamente o texto a seguir e responda às questões de 17 a 24.
04.08.2024
‘We have reached the limit.’ Clash with Elon Musk prompts calls for social media controls in Brazil
London (CNN) — Brazil’s attorney general has called for social media platforms in the country to be regulated after Elon Musk threatened to disobey a court order banning certain accounts on X and lashed out against “aggressive censorship.”
In a post on X Sunday, Attorney General Jorge Messias wrote: “It is urgent to regulate social networks. We cannot live in a society in which billionaires domiciled abroad have control of social networks and put themselves in a position to violate the rule of law, failing to comply with court orders and threatening our authorities.”
In a statement, Brazil’s Supreme Court described Musk’s defiance as a “flagrant” obstruction of justice and said he should be investigated by the police. Supreme Court Justice Alexandre de Moraes announced Sunday that he would open an inquiry into the billionaire businessman who owns X.
The standoff is the latest clash between authorities around the world and Musk – a self-declared “free speech absolutist” who has relaxed X’s content moderation policies and reinstated a number of previously blocked accounts after buying the company, formerly known as Twitter, in 2022.
Orlando Silva, a Brazilian lawmaker aligned with the country’s left-wing government, said he would propose a “responsibilities regime for these digital platforms.” “We have reached the limit!” he posted on X, adding that Musk had disrespected the judiciary.
On Saturday, X’s global government affairs team posted that it had been “forced by court decisions to block certain popular accounts in Brazil” and threatened with “daily fines” for non-compliance.
“We do not know which posts are alleged to violate the law. We are prohibited from saying which court or judge issued the order, or on what grounds,” they wrote. They do not believe the orders are constitutional and will challenge them legally where possible, they added.
The Supreme Court had ordered that the accounts be blocked as part of its ongoing investigation into “digital militias,” which, among other things, is looking into the spread of misinformation and incitement of crime under the government of former far-right President Jair Bolsonaro.
Social media platforms have been widely viewed as a catalyst for riots in Brazil that took place on January 8 last year, when hundreds of protesters broke into federal government buildings in the capital Brasilia, in scenes reminiscent of the January 6, 2021, insurrection in the United States.
Musk suggested that Moraes was behind the ban, writing Sunday on X that the judge had “brazenly and repeatedly betrayed the constitution and people of Brazil. He should resign or be impeached.”
In a separate post Saturday, he called the court’s decision to block the accounts “aggressive censorship” that “appears to violate the law and will of the people of Brazil.” He said X would defy the court’s order and lift all restrictions.
“As a result, we will probably lose all revenue in Brazil and have to shut down our office there. But principles matter more than profit,” he noted.
X has faced criticism for accommodating government censorship demands in the past, with Musk saying the company has no choice but to comply. For example, it blocked some X accounts in Turkey at the behest of the government ahead of the country’s elections last year, while at the same time contesting the orders in court.
(Internet: <https://edition.cnn.com/2024/04/08/tech/elon-musk-brazil-investigation/index.html> )
From the sentence “Social media platforms have been widely viewed as a catalyst for riots in Brazil that took place on January 8 last year, when hundreds of protesters broke into federal government buildings in the capital Brasilia, in scenes reminiscent of the January 6, 2021, insurrection in the United States”, it is possible to say that
Provas
Leia atentamente o texto a seguir e responda às questões de 17 a 24.
04.08.2024
‘We have reached the limit.’ Clash with Elon Musk prompts calls for social media controls in Brazil
London (CNN) — Brazil’s attorney general has called for social media platforms in the country to be regulated after Elon Musk threatened to disobey a court order banning certain accounts on X and lashed out against “aggressive censorship.”
In a post on X Sunday, Attorney General Jorge Messias wrote: “It is urgent to regulate social networks. We cannot live in a society in which billionaires domiciled abroad have control of social networks and put themselves in a position to violate the rule of law, failing to comply with court orders and threatening our authorities.”
In a statement, Brazil’s Supreme Court described Musk’s defiance as a “flagrant” obstruction of justice and said he should be investigated by the police. Supreme Court Justice Alexandre de Moraes announced Sunday that he would open an inquiry into the billionaire businessman who owns X.
The standoff is the latest clash between authorities around the world and Musk – a self-declared “free speech absolutist” who has relaxed X’s content moderation policies and reinstated a number of previously blocked accounts after buying the company, formerly known as Twitter, in 2022.
Orlando Silva, a Brazilian lawmaker aligned with the country’s left-wing government, said he would propose a “responsibilities regime for these digital platforms.” “We have reached the limit!” he posted on X, adding that Musk had disrespected the judiciary.
On Saturday, X’s global government affairs team posted that it had been “forced by court decisions to block certain popular accounts in Brazil” and threatened with “daily fines” for non-compliance.
“We do not know which posts are alleged to violate the law. We are prohibited from saying which court or judge issued the order, or on what grounds,” they wrote. They do not believe the orders are constitutional and will challenge them legally where possible, they added.
The Supreme Court had ordered that the accounts be blocked as part of its ongoing investigation into “digital militias,” which, among other things, is looking into the spread of misinformation and incitement of crime under the government of former far-right President Jair Bolsonaro.
Social media platforms have been widely viewed as a catalyst for riots in Brazil that took place on January 8 last year, when hundreds of protesters broke into federal government buildings in the capital Brasilia, in scenes reminiscent of the January 6, 2021, insurrection in the United States.
Musk suggested that Moraes was behind the ban, writing Sunday on X that the judge had “brazenly and repeatedly betrayed the constitution and people of Brazil. He should resign or be impeached.”
In a separate post Saturday, he called the court’s decision to block the accounts “aggressive censorship” that “appears to violate the law and will of the people of Brazil.” He said X would defy the court’s order and lift all restrictions.
“As a result, we will probably lose all revenue in Brazil and have to shut down our office there. But principles matter more than profit,” he noted.
X has faced criticism for accommodating government censorship demands in the past, with Musk saying the company has no choice but to comply. For example, it blocked some X accounts in Turkey at the behest of the government ahead of the country’s elections last year, while at the same time contesting the orders in court.
(Internet: <https://edition.cnn.com/2024/04/08/tech/elon-musk-brazil-investigation/index.html> )
Choose the alternative that better substitutes the underlined preposition in “On Saturday, X’s global government affairs team posted that it had been ‘forced by court decisions to block certain popular accounts in Brazil’ and threatened with ‘daily fines’ for non-compliance”.
Provas
Caderno Container