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Analyzing dynamic behavior of land use and land surface temperature in the city of Imphal, India

Neog Rituraj

Acta Geophysica

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2021

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Vol. 69, no. 6

2275--2290

EN

The study has been conducted over the Imphal city using multi-temporal satellite imageries. The study investigated the pattern land surface temperature (LST) development over the hill city of Imphal and its relation to land use pattern and population density. The result revealed an ascending growth of LST as a consequence of population growth and rapid land use dynamics. The Imphal city exhibited a remarkable change in the land use structure, especially in the built-up land, vegetation and crop land. Addition of built-up land of 667.44 hectares in the city territory has consequently upsurged the mean LST of the city from 23.23 °C to 30.30 °C in summer and 14.74–18.10 °C in winter during the period of 26 years (1994–2020). Summer season witnessed a consistently increasing intensity of LST in the city whereas winter depicted a completely opposite scenario during 1994–2020. Among all the land use classes, built-up land expressed maximum LST dynamics in both seasons during the period 1994 to 2020. The high positive correlation coefficient between built-up land with LST and strong negative correlation between vegetation cover and LST paved the way for maximum LST development in the city province.

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Tribologiczne aspekty procesu skrawania narzędziami z niskostopowej stali szybkotnącej SW3S2

Jaworski J.

Tribologia

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2008

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nr 2

215-222

EN

The way of wear or destruction of the tool determines the material selection for a proper tool. This selection is facilitated by the characteristics, which determine relations between the structure and the properties of the tool material, on the one hand, and the tool working conditions and the way of wear, on the other. The permissible cutting speed level is determined primarily by the temperature at the contact surface of the tool and the stock material. There is a relationship between the temperature and wear of the cutting edge surface of the tool caused by a progressive loss of its hardness. When the temperature in the cutting process exceeds the value at which the cutting edge of the tool loses its hardness, then dynamic recrystallization causes its immediate catastrophic wear, even at a small value of dullness. The nature of temperature distribution qualifies the place of the wear of the cutting edge. At a small cut layer thickness the maximum temperature occurs near the cutting edge which is the reason of wear of the cutting edge on the flank. Together with the raising thickness of the cut layer, the highest temperature moves away from the cutting edge and its centre lies in the place of contact of the chip and the rake surface. For such cutting conditions, wear in the form of a groove on the rake surface is characteristic. For the same tool material and stock material the thickness of the cut layer has an influence on the temperature distribution, and the cutting speed has an influence - on the value of the temperature. It is known that the growth of cut layer thickness is followed by high increase of build-up and, simultaneously, the range of cutting speeds restricts, where it occurs. Figure 2 shows the cutting forces, the length of contact line bu and chip upset coefficient, for the edges made of SW3S2, which are less than for those made of SW7M. A decrease of the parameters becomes more intensive at the higher cutting speeds, out of the range of build-up creating, vc>60 m/min for both kind of steel. The mean friction coefficient on the friction surface is the basic factor influencing on build-up creating. As it is shown in Fig. 3, the build-ups, occurring in the conditions, are different from one another. On the edge of cuter, made of SW7M, a massive and high buildup occurs which enlarges the tool rake. A build-up with the shape prevents the tool flank against direct contact with the cutting surface and facilitates the chip rising process. The height of the buildup, on the cutting edge made of SW3S2, is smaller so it can be supposed that its influence on decrease of friction on the tool flank is inconsiderable which prevents the cutter against the heat created in the area of rising chip. Consequently the maximum temperature in the cutter rises in the vicinity of the side cutting edge under the base of the build-up. It was shown experimentally that for the thick cut layers the build-up mainly determines the position of the point of the highest temperature on the cutting edge.

3

The TEM study of structure of 1H18N9T stainless steel buildups

Presz W., Kaczorowski M.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

393--396

EN

Purpose: The reason of investigation was finding the answer of the question what was the reason of extreme hardness of build-ups created during bulk metal forming processes of austenitic stainless steel. Design/methodology/approach: The studies were conducted using transmission electron microscopy (TEM). Since very specific specimens special method for thin foil preparation were elaborated. Thin foil method was chose because it was only one which supply both structure and diffraction information. Findings: On the basis of careful analysis structural and electron diffraction pattern it was proposed that simultaneously to very well known strengthening mechanisms like grain refinement and dislocation density increase, the additional mechanism can not be excluded. Based mostly on the electron diffraction pattern (appearance of forbidden reflexes for FCC) it is proposed that this additional mechanism could be the marthensitic transformation caused by very high plastic deformation. Practical implications: At this moment it is difficult to point out the practical implications of the result however the mechanism proposed in this elaboration might be used in design of high strength materials. Originality/value: The main achievement of this investigation is TEM results which analysis allow to propose that an extra-mechanism for strengthening of 1H18N9 stainless steel is marthensitic transformation involved with high plastic deformation in build-ups. Additionally the special method of thin foils preparation was elaborated.

4

Automatic detection of flats on the rolling stock wheels

Madejski J.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 16, nr 1-2

160--163

EN

Purpose: The goal of this work was increasing safety of tram, metro and trams operation. Design/methodology/approach: The accelerometers were fixed directly to the rail to provide the system with the best defect signal quality. Analysis of the acoustic signals collected using microphones proved that too much of the background noise limited their usefulness. Findings: It has been proven that all wheel geometry defects can be reliably detected and classified according to the experimentally established defect categories. Research limitations/implications: Exact measurements of the wheel defect geometry may be possible only after collecting huge signals time series along with the wheel measurements taken with other methods to reveal the relationships between them. This goal is hard to achieve, as the system performs already very well, and such experiments would be very costly and time consuming. Practical implications: Integrated wheel geometrical data collected from the wheel ovality, flat spots, and build-up detection system along with the wheel profile information have eliminated all derailments due to faulty wheel geometry. Originality/value: The system presented is the first wheel monitoring application in Poland, its unique feature is that it can be used at low speeds, like those allowed in depots.