Machining Process Monitoring System Using Audible Energy Sound Sensors

This work reports on the approach for the development of a machining process monitoring system based on audible sound sensors. Audible sound energy appears as one of the most practical techniques since it can serve to replace the traditional ability of the operator, based on his experience and senses (mainly vision and hearing), to determine the process state and react adequately to any machine performance decay. This technique has been attempted for decision making on machining process conditions but it has not been extensively studied yet for applications in industrial process monitoring. The main critical issues related to the employment of this technology in industry are the need to protect the sensor from the hazardous machining environment (cutting fluids and metal chips) and the environment noise (from adjacent machines, motors, conveyors or other processes) that may contaminate the relevant signals during machining. The principal benefits of audible sound sensors for machining process monitoring are associated with the nature of the sensors employed in the acquisition of the signals. These are, in general, easy to mount on the machine tool, in particular near the machining point, with little or no interference with the machine, the tool, the workpiece or the chip formation. Besides, these sensors, basically microphones, are easy to use in combination with standard phonometers or spectrum analysers. These characteristics of audible sound sensors make the realization of the monitoring procedure quite straightforward. In addition, their maintenance is simple since they only require a careful handling to avoid being hit or damaged. Accordingly, they usually provide for a favourable cost/benefit ratio. The key novelties of the approach proposed in this work are, on the one hand, the application of a systematic methodology to set up the cutting trials allowing for a better comparison with other similar experimental works and, as a result, the advance in the standardization for the development of such systems. On the other hand, the independent signal analysis of the noise generated by the machine used for the cutting trials and by the working environment allows to filter this noise out of the signals obtained during the actual material processing. Lastly, the possibility has been verified to apply the results of this approach for the development of process monitoring procedures based on sensors of a different type, in particular acoustic emission sensors, where the stress waves produced within the work material do not travel through air but only in the work material itself. The combined application of audible sound energy sensors and acoustic emission sensors could allow for the acquisition of more exhaustive information from both low frequency (audible sound) and high frequency (acoustic emission) acoustic signal analysis. This would decidedly contribute to the realization of the concept of sensor fusion technology for process monitoring

Efek Fermentasi dengan Saccharomyces Cerevisiae terhadap Karakteristik Biokimia Tapioka

Saccharomyces cerevisiae diketahui sebagai khamir penghasil enzim ekstraseluler. Penelitian ini bertujuan untuk mengetahui peranan enzim ektraseluler S. cereviciae dalam pembuatan tapioka dengan mengamati Perubahan biokimia pati. Sebanyak 1010 sel ml-1 inokulum S.cerevisiae diinokulasikan ke dalam suspensi tapioka, kemudian difermentasi selama 12 jam, 36 jam, dan 48 jam pada suhu ruang (30oC). Hasil penelitian menunjukkan bahwa S.cerevisiae mampu tumbuh selama fermentasi dan memperbaiki sifat biokimia tapioka. Tapioka hasil fermentasi dengan S.cerevisiae memiliki kadar protein (2,17%) secara signifikan lebih tinggi dari kadar protein tapioka alami (0,28%). Sementara itu, kadar amilosa tapioka terfermentasi (24,83%) lebih rendah dari amilosa tapioka alami (28,57%). Dilain pihak, penambahan S.cerevsiae meningkatkan kadar Fe, Mg, dan Ca tapioka, tetapi kadar Zn nya menurun. Struktur granula pati tapioka terfermentasi juga menunjukkan adanya erosi di bagian tepi granula. Penelitian ini menunjukkan bahwa penambahan S.cerevisiae dapat digunakan sebagai agensia modifikasi tapioka untuk meningkatkan kadar protein dan daya kelarutan

Durability and variability of the acoustical performance of rubberized road surfaces

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Las funciones en la resolución de problemas

En este trabajo presentamos algunas reflexiones y una propuesta acerca de la enseñanza por resolución de problemas, siendo el eje de esta última la aplicación y discusión del concepto de Función. En las carreras ´no matemáticas´ sin relegar el papel fundamental de la formación en lo teórico-conceptual los esfuerzos se desplazan hacia la aplicación de los métodos matemáticos en la resolución de problemas de las ciencias en general. Dado que el desarrollo mismo de la ciencia puede entenderse como resultado de la búsqueda de solución a los distintos problemas que aquejan al hombre, creemos que la ´enseñanza por resolución de problemas´ coadyuva a promover el cambio conceptual y metodológico que requiere actualmente el sistema educativo en general. La propuesta consiste esencialmente en el planteo de una situación problemática familiar al estudiante para, a partir de allí y siempre bajo la guía y supervisión del docente, proceder a su discusión, al planteo de conjeturas e hipótesis, resolución, verificación, etc. En este caso el problema requiere del concepto de función, concepto básico y esencial en toda disciplina que acuda a los modelos matemáticos. Creemos que este presenta características que lo signan como concepto fuerza en la implementación del cambio pretendido; que su uso en el marco de la resolución de problemas coadyuva a tal propósito pues, entre otras bondades, las funciones se caracterizan por tener cuatro representaciones o codificaciones distintas -gráfica, numérica, analítica, verbal- cada una de las cuales expresa aspectos o propiedades didácticas no equivalentes ni equiparables entre sí, lo cual, además de ampliar el espectro de posibilidades para trabajar con el estudiante, proporciona elementos para una mejor evaluación del mismo (asimilando la comprensión del concepto a la capacidad de recodificar la información desde una representación a otra)

Matemática, informática y la “renegociación” de normas preexistentes

El deseo de dar respuestas a interrogantes tales como ¿Qué tipo de conocimientos requiere una sociedad en constante transformación?; ¿qué capacidades o estrategias debemos promover para favorecer la formación de individuos social, cultural e intelectualmente plenos, comprometidos con su entorno?. ¿Será posible contemplar en las planificaciones pedagógicas la secuencia evolutiva natural de la vida (ambiente enseñanzas- memorias-comportamiento individual-comportamiento social-enseñanzas-ambiente), los tiempos biológicos requeridos para consolidar, almacenar y dar funcionalidad a la información adquirida?; ¿imponerse a la aceleración (o inercia) de los tiempos administrativos? nos lleva a reflexionar sobre la propia práctica, considerar el rediseño de la misma, a proponernos finalmente un plan de trabajo cuya estructuración contemple tanto cuestiones atinentes a la propia disciplina como, y especialmente, a todas aquellas otras que tuvieran que ver con una positiva integración Sociedad, Ciencia y Tecnología, S/C/T. En una primer etapa procedimos a investigar, caracterizar y explicitar una serie de normas “sociomatemáticas” que llamamos preexistentes y que a nuestro juicio serían inhibidoras del aprendizaje y relativas al contexto sociocultural en el que nos movemos. Por contraposición establecimos normas a renegociar con nuestros estudiantes, las que llamamos “emergentes”. Concretada la primer etapa del plan (sistema de interpretación, diseño de instrumentos para la intervención pedagógica) generamos experiencias participativas con la presencia de estudiantes y docentes a los fines de implementar los instrumentos diseñados, observar y evaluar la calidad de los mismos, el sistema de interpretación en sí. El presente trabajo trata de algunos resultados y conclusiones obtenidas en esta segunda etapa del plan

Comparison between adult and foetal adnexa derived equine post-natal mesenchymal stem cells

Background Little is known about the differences among adult and foetal equine mesenchymal stem cells (MSCs), and no data exist about their comparative ultrastructural morphology. The aim of this study was to describe and compare characteristics, immune properties, and ultrastructural morphology of equine adult (bone marrow: BM, and adipose tissue: AT) and foetal adnexa derived (umbilical cord blood: UCB, and Wharton's jelly: WJ) MSCs. Results No differences were observed in proliferation during the first 3 passages. While migration ability was similar among cells, foetal MSCs showed a higher adhesion ability, forming smaller spheroids after hanging drop culture (P < 0.05). All MSCs differentiated toward adipogenic, chondrogenic and osteogenic lineages, only tenogenic differentiation was less evident for WJ-MSCs. Data obtained by PCR confirmed MHC1 expression and lack of MHC2 expression in all four cell types. Foetal adnexa MSCs were positive for genes specific for anti-inflammatory and angiogenic factors (IL6, IL8, IL beta 1) and WJ-MSCs were the only positive for OCT4 pluripotency gene. At immunofluorescence all cells expressed typical mesenchymal markers (alpha-SMA, N-cadherin), except for BM-MSCs, which did not express N-cadherin. By transmission electron microscopy, it was observed that WJ-MSCs had a higher (P < 0.05) number of microvesicles compared to adult MSCs, and UCB-MSCs showed more microvesicles than BM-MSCs (P < 0.05). AT-MSCs had a lower number of mitochondria than WJ-MSCs (P < 0.05), and mitochondrial area was higher for WJ-MSCs compared to UCB and AT-MSCs (P < 0.05). Conclusions Results demonstrate that MSCs from adult and foetal tissues have different characteristics, and foetal MSCs, particularly WJ derived ones, seem to have some charactestics that warrant further investigation into potential advantages for clinical application

Cellular senescence in vascular wall mesenchymal stromal cells, a possible contribution to the development of aortic aneurysm

Cellular senescence is a hallmark of ageing and it plays a key role in the development of age-related diseases. Abdominal aortic aneurysm (AAA) is an age related degenerative vascular disorder, characterized by a progressive dilatation of the vascular wall and high risk of rupture over time. Nowadays, no pharmacological therapies are available and the understanding of the molecular mechanisms that lead to AAA onset and development are poorly defined. In this study we investigated the cellular features of senescence in vascular mesenchymal stromal cells, isolated from pathological (AAA – MSCs) and healthy (h – MSCs) segments of human abdominal aorta and their implication in impairing the vascular repair ability of MSCs. Cell proliferation, ROS production, cell surface area, the expression of cyclin dependent kinase inhibitors p21CIP1 and p16INK4a, the activation of the DNA damage response and a dysregulated autophagy showed a senescent state in AAA - MSCs compared to h-MSCs. Moreover, a reduced ability to differentiate toward endothelial cells was observed in AAA – MSCs. All these data suggest that the accumulation of senescent vascular MSCs over time impairs their remodeling ability during ageing. This condition could support the onset and development of AAA

Iron Deficiency is Related to Depressive Symptoms in United States Nonpregnant Women of Reproductive Age : A Cross-Sectional Analysis of NHANES 2005-2010

This study was supported by the John L. Beard Program Endowment Fund.Peer reviewedPublisher PD

Perceptions of Audio Computer-Assisted Self-Interviewing (ACASI) among Women in an HIV-Positive Prevention Program

Background: Audio Computer-Assisted Self Interviewing (ACASI) has improved the reliability and accuracy of self-reported HIV health and risk behavior data, yet few studies account for how participants experience the data collection process. Methodology/Principal Findings: This exploratory qualitative analysis aimed to better understand the experience and implications of using ACASI among HIV-positive women participating in sexual risk reduction interventions in Chicago (n = 12) and Philadelphia (n = 18). Strategies of Grounded Theory were used to explore participants ’ ACASI experiences. Conclusion/Significance: Key themes we identified included themes that could be attributed to the ACASI and other methods of data collection (e.g., paper-based self-administered questionnaire or face-to-face interviews). The key themes were usability; privacy and honesty; socially desirable responses and avoiding judgment; and unintentional discomfort resulting from recalling risky behavior using the ACASI. Despite both positive and negative findings about the ACASI experience, we conclude that ACASI is in general an appropriate method for collecting sensitive data about HIV/AIDS risk behaviors among HIV-positive women because it seemed to ensure privacy in the study population allowing for mor