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Volumes determination in terms of various data density and surface diversity

Sokol S., Bajtala M., Lipták M., Brunčák P.

Journal of Sustainable Mining

2014

Vol. 13, iss. 4

23--27

Purpose The aim of this paper is to assess the impact of input data density and diversity on surfaces obtained using the terrestrial laser scanning (TLS) method for creating digital elevation model (DEM). For this we can use several approaches, while we have chosen an intermediary parameter – volume calculation, which is in practice the most frequently requested requirement from surveyors. Methods Precise terrestrial measurement and terrestrial laser scanning were used to ensure that detailed knowledge about the surface and volumes of two piles of earth and a stone pit in comparison with theoretical defined surfaces was obtained. Results Mathematically defined surfaces generally have smooth shapes, and thus the effect of different density on the input data is less apparent in the final comparison of volumes. In our case the results for most of the different interpolation methods and the different density of the input data was less than 0.5%. From the experimental measurements of the two earth bodies and the quarry, which have an irregular shape with unsmooth surfaces, we can only test the relative precision of the calculated volumes to the data with the highest density. Experimental measurements in the area of the quarry, where the scanned surface was uneven and considerably different in height, confirmed the assumption that a vastly irregular surface should exhibit more significant variations than a smooth surface, but for the nearest neighbour method relative errors under 1% were achieved. Practical implications According to the results from the analysis above, the lower density of input data we have, the lower the precision of calculating volumes we can assume, but it is interesting that we did not achieved significantly worse results with strongly irregular surfaces compared to a less irregular surface. Originality/ value The input values for the analysis of theoretically defined surfaces were obtained by the calculation of integral calculus and earth-moving bodies and quarry from an experimental measurement terrestrial laser scanning method and were used in Slovakia for the first time.

Investigation of the air permeability of socks knitted from yarns with peculiar properties

Čiukas R., Abramavičiute J.

Fibres & Textiles in Eastern Europe

2010

Vol. 18, no. 1 (78)

84--88

This paper presents a study on the air permeability of socks manufactured using the yarns of new kinds of fibres, such as soybean, bamboo, cotton/seacells and bamboo/flax. The air permeability of plain pure knits and plated knits of textured polyamide (PA) and elastane (Lycra) wrapped with textured polyamide threads was investigated. It was determined that higher air permeability is characteristic for knits produced from natural yarns, a lower permeability for knits with textured PA, and the lowest for knits with Lycra threads. Textured PA or Lycra threads change the structure of plated knits as the construction of such knits are thicker and tighter. The variation in air permeability depending on the area density, linear density, loop length and tightness factor of plain and plated plain knits was discussed.

W artykule przedstawiono badania przepuszczalności powietrza skarpet wykonanych z przędz zawierających nowe rodzaje włókien, takich jak: sojowe, bambusowe, mieszanki bawełny i włókien z alg morskich oraz bambusu z lnem. Ponadto badano skarpety wykonane z dzianin lewo-prawych, w których zastosowano przędze polimerowe (PA) i elastomerowe (Lycra) owinięte nitką poliamidową. Stwierdzono, ze wyższa przepuszczalność powietrza posiadają skarpety dziane produkowane z włókien naturalnych, niższa przepuszczalność powietrza wykazują skarpety dziane z przędz poliamidowych, a najniższa – skarpety dziane z udziałem Lycry. Stosowanie Przędze wykonanych z teksturowanego PA oraz przędz elastomerowych zmieniają strukturę dzianin tworząc ja grubszą i bardziej zwartą. Przeprowadzono dyskusje różnic przepuszczalności powietrza spowodowaną masą powierzchniowa dzianiny, masa liniowa przędz, długością oczek i gęstością dzianiny.