Detection and measurement of phase transformation in steels using electromagnetic sensors – experimental results and modelling simulations.

An electromagnetic (EM) sensor, capable of detecting the formation of ferromagnetic ferrite from paramagnetic austenite below the Curie temperature, has been developed and assessed. In this article, results obtained using an a.c. EM sensor for a medium (0.45 wt pct)—carbon steel slow cooled through its transformation-temperature range are presented. It was found that the EM sensor can successfully detect the formation of ferrite below the Curie temperature, but that the transimpedance values can be significantly affected by the formation of a decarburized ferrite ring around the samples. It was also found that the transimpedance value is monotonically (nonlinearly) related to the ferrite volume fraction and depends on the morphology/distribution of the ferromagnetic phase and, hence, is influenced by the prior-austenite grain size. Results from finite-element (FE) simulations designed to enable prediction of the transimpedance from the microstructure are also presented, showing that two-dimensional (2-D) FE simulations can be successfully used to model the experimental trends observed. The combination of modeling and measurement has shown that EM sensors can be used to indirectly monitor the ferrite transformation (below the Curie temperature), thus providing a measure of ferrite volume fraction and also a means of identifying the ferrite distribution in the microstructure

Magnetic evaluation of microstructure changes in 9Cr-1Mo and 2.25Cr-1Mo steels using electromagnetic sensors

This paper presents results from a multi-frequency electromagnetic sensor used to evaluate the microstructural changes in 9Cr-1Mo and 2.25Cr-1Mo power generation steels after tempering and elevated temperature service exposure. Electromagnetic sensors detect microstructural changes in steels due to changes in the relative permeability and resistivity. It was found that the low frequency inductance value is particularly sensitive to the different relative permeability values of both steels in the different microstructural conditions. The changes in relative permeability have been quantitatively correlated with the microstructural changes due to tempering and long-term thermal exposure, in particular to changes in martensitic/bainitic lath size and number density of carbide precipitates that determine the mean free path to reversible domain wall motion. The role of these microstructural features on pinning of magnetic domain wall motion is discussed

Human papillomavirus status and cervical abnormalities in women from public and private health care in Rio de Janeiro State, Brazil Papilomavírus humano e anormalidades cervicais em mulheres do sistema de saúde privado e público no Estado do Rio de Janeiro, Brasil

This article reports the HPV status and cervical cytological abnormalities in patients attended at public and private gynecological services from Rio de Janeiro State. It also comments the performance of each HPV DNA tests used. A set of 454 women from private health clinics was tested by routine Capture Hybrid II HPV DNA assay. Among these, 58.4% presented HPV and nearly 90% of them were infected by high risk HPV types. However, this group presented few premalignant cervical lesions and no invasive cervical cancer was registered. We also studied 220 women from low income class attended at public health system. They were HPV tested by polymerase chain reaction using My09/11 primers followed by HPV typing with E6 specific primers. The overall HPV prevalence was 77.3%. They also showed a high percentage of high squamous intraepithelial lesion-HSIL (26.3%), and invasive cervical carcinoma (16.3%). HPV infection was found in 93.1% and 94.4% of them, respectively. The mean ages in both groups were 31.5 and 38 years, respectively. In series 1, HPV prevalence declined with age, data consistent with viral transient infection. In series 2, HPV prevalence did not decline, independent of age interval, supporting not only the idea of viral persistence into this group, but also regional epidemiological variations in the same geographic area. Significant cytological differences were seen between both groups. Normal and benign cases were the most prevalent cytological findings in series 1 while pre-malignant lesions were the most common diagnosis in the series 2. HPV prevalence in normal cases were statistically higher than those from series 1 (p < 0.001), indicating a higher exposure to HPV infection. Women from both samples were referred for previous abnormal cytology. However, socio-demographic evidence shows that women from series 1 have access to treatment more easily and faster than women from series 2 before the development of pre-malignant lesions. These data provides baseline support for the role of social inequalities linked to high risk HPV infection leading to cervical cancer. Broadly screening programs and the development of safe and effective vaccines against HPV would diminish the toll of this disease that affect mainly poor women.<br>Este artigo analisa a infecção por HPV e anormalidades citológicas cervicais encontradas em pacientes atendidas em serviços ginecológicos dos sistemas de saúde público e privado do estado do Rio de Janeiro. O trabalho também avalia os testes utilizados para detecção de DNA do HPV em cada população estudada. Um grupo de 454 mulheres oriundas de serviços da rede privada de saúde foi testado por Captura do Híbrido II. Destas, 58,4% apresentaram infecção por HPV e cerca de 90% delas estavam infectadas por HPV de alto risco. Este grupo, entretanto, apresentava poucos casos de lesões cervicais pré-malígnas e nenhum caso de câncer. Estudamos, também, 220 mulheres de baixo nível econômico atendidas no serviço de saúde pública que foram testadas para HPV pela reação da polimerase em cadeia utilizando-se os oligonucleotídeos My09/My11. A identificação dos tipos foi efetuada por amplificação com oligonucleotídeos específicos para a região E6 do genoma viral. A prevalência de HPV nesta população foi de 77.3%, observando-se uma alta porcentagem de casos de neoplasias intraepiteliais cervicais de alto grau (26,3%) e de carcinoma cervical invasivo (16,3%). A infecção por HPV foi achada em, respectivamente, 93,1% e 94,4% destes casos. A média de idade em ambos os grupos era de 31,5 e 38 anos, respectivamente. Na série 1, a prevalência da infecção por HPV decresce com a idade, enquanto na série 2 ela não desaparece, dando suporte não só à idéia de persistência viral neste grupo, mas também a variações epidemiológicas na mesma área geográfica. Diferenças significativas foram vistas nos dois grupos. Casos normais e benignos foram incidentes na série 1, enquanto as lesões malígnas predominaram na série 2. Ao contrário, casos normais infectados por HPV eram prevalentes na série 2 (p < 0.001), indicando maior exposição ao vírus. Embora as mulheres de ambos os grupos tenham sido incluídas no estudo por apresentarem citologia anormal, evidências sócio-demográficas demonstram que mulheres da série 1 tem acesso mais fácil e rápido ao tratamento do que as mulheres da série 2 antes que as lesões pré-malígnas se desenvolvam. Estes resultados fornecem dados sobre o papel das desigualdades sociais associadas à infecção por HPV de alto risco na progressão do câncer cervical. Programas de prevenção abrangentes e o desenvolvimento de vacinas eficazes e seguras contra o HPV poderiam reduzir o tributo desta doença que afeta principalmente mulheres pobres