Rail Corrugation of High-Speed Railway Induced by Rail Grinding

Rail corrugation is a common railway defect that involves diverse and complex factors. Rail grinding is also the most commonly used method to address corrugations. Through numerous irregularity tests and one-third octave frequency spectrum analyses, this study determined the characteristics and development process for rail corrugation on high-speed rail tracks. The vibration transmission properties of the grinding train were tested using the force hammer impacting method. Thereafter, using a simulation, the influence of the vertical vibration behavior of the grinding stone and the stiffness of the hydraulics were determined. Through a series of field tests and numerical simulations, this study revealed a clear correlation between rail corrugation and rail grinding and confirmed that the technical operation of rail grinding is closely associated with regular grinding marks at a wavelength of approximately 60 mm on rail surfaces. The combination of the natural vibration of the grinding stone (frequency of 60 Hz) and an inappropriate operational process can aggravate the grinding marks on the rail surfaces, thereby forming an initial excitation of rail corrugation. Although a large number of irregularity tests are performed after rail grinding, these wavelength-fixing grinding marks can cause the formation and development of rail corrugation. Suggestions for improving the high-speed rail-grinding technology are also provided.

Grinding Songs from Goa

The aim of this paper is to bring an analysis of oviyos, folkloric songs that Indian women from the Hindu community of Goa, former Portuguese colony in India used to sing while working at the grinding stone. These songs, a sample of Goan folklore, were collected by Heta Pandit in the book Grinding Stories. Songs from Goa (2018), based on her field work with singers Subhadra Arjun Gaus, Saraswati, Dutta Sawant and Sarojini Bhiva Gaonkar. The songs, sung in a dialect of Marathi-Konkani, were transcribed into English. These elaborate songs are of psychological and social significance as they provide a release from a sometimes harsh reality, at the same time they are an invaluable cultural document. They have been analyzed from the perspective of Goan folklore as discussed by Phaldesai (2011), the meaning of folkloric narratives (Dundes, 2007) and a reflection on the genre oviyos (Jassal, 2012).

Experimental Study on The Effect of Cross Feed of Surface Grinding on the Vibration and the Surface Roughness of Hardened Tool Steel OCR12VM

The grinding process is a machining process to obtain qualified surface roughness levels and high dimensional accuracy. There are two types of processes in the grinding process, namely the roughening and finishing processes. The vibration effect of the roughing process can damage and shorten the life of the tool/machine, while in the finishing process, the effect of vibration will reduce the dimensional accuracy, shape, and surface smoothness of the workpiece. This study aims to determine the effect of crossfeed on the amplitude of vibration and surface roughness of the workpiece on the surface grinding process. The materials used are hardened tool steel OCR12VM with a variety of grinding stone types A46QV and A80LV made of aluminum oxide. The Variables of process parameters are crossfeed (mm / step) and depth of cut (mm). The measurement of vibrations uses an accelerometer, which is processed by the math CAD program in the form of amplitude and frequency. For surface roughness measurements, it is used the MT-301 surface test with 5 sample points and a sample length of 0.8 mm. The results show that the greater the cross-feed value, the bigger the amplitude of the vibration level and the surface roughness of the workpiece. The magnitude of the amplitude of the vibration on the acceleration that occurs in the grinding stone type A46QV starts from 6,7369 -18.7525 g.rms, while the grinding stone type A80LV starts from 5.0904 g.rms to 18.2821 g.rms. The surface roughness achieved in both grit 46 and grit 80 is from N3 to N5.

Men at work: Grinding stone production by the experts and others in northern Ethiopia

It is necessary to access the oral forms of local histories often held in traditional African communities to help us understand the African past and avoid framing interpretations solely in terms of Western epistemologies. Ethnoarchaeological fieldwork was carried out in villages in the Gulo Makeda region of northeastern Tigrai, northern Ethiopia, where access to mechanical mills has only been available in the last few decades. Individuals in this area still have knowledge and memory of manufacturing, using and discarding grinding stones. Interviews were held with male advisors who shared their knowledge and expertise about the entire process of manufacturing grinding stones. To move beyond understanding just the technical aspects of grinding stone manufacturing (what and how), the theory and methods associated with the chaîne opératoire and design theory were incorporated into the research to allow discovery of intricate socio-economic interrelationships (how and why) that exist through grinding manufacture within this culture. Manufacturing offers opportunities for socialization, cooperation and community engagement. Through ethnoarchaeology it became clear that the manufacturing of grinding stones in northeastern Tigrai is a complex process requiring design decisions, skills, knowledge, and social interaction that builds interpersonal relationships. By arranging two separate manufacturing sessions, one with experts and one with non-experts, comparisons were made of technological and social differences between experts and non-experts. The individuals who are experts in manufacturing grinding stones made higher quality grinding stones than the non-experts. The experts are also afforded a special respect by others, as they are the creators of the technology “necessary for life” in a culture traditionally dependent on cereal flours for sustenance. Potentially this respect for experts could be true for the past as well. Since the grinding stone artifacts from Mezber are large stones, likely meant to produce significant amounts of flour, they would have been important to daily life. Those who manufactured these tools important for subsistence would likely have been considered important individuals in the community.

Obras en el molino de la Mina de la villa de Alcalá de Guadaíra (1796-1820): informes de Cayetano Vélez, Manuel Cintora y José Echamoros

Resumen: El objeto del presente estudio es dar a conocer las obras que se llevaron a cabo entre los años 1796 y 1820 en el Molino de la Mina (Alcalá de Guadaíra, Sevilla) y que consistieron en poner a funcionar una segunda piedra de moler. Finalidad que no se consiguió debido a los inconvenientes técnicos y de caudal del referido molino. Para ello se hicieron unos informes de las mencionadas obras en las que intervinieron Cayetano Vélez, Manuel Cintora y José Echamoros.Abstract: The objective of the present study is to make known the works that were carried out between the years 1796 and 1820 in Mine Mill (Alcalá de Guadaíra, Seville) and which consisted in putting to work a second grinding stone. This purpose was not achieved due to the disadvantages technical and flow characteristics of said mill. For this purpose, reports were made of the mentioned works in which Cayetano Vélez, Manuel Cintora and José Echamoros.