• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.251-259
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• 2010

It is presented in this study a new efficient intelligent machining strategy, which can be used to remove the uncut volume at the boundary region of curved surfaces caused by cutter interference. The geometric form definitions and recognition of topological features of the surface triangulation mesh are used to generate cutter paths along successive and interconnected steepest pathways, that minimize the cusp height left after flat end milling. In order to machine the uncut volume gradually, the z-map cutter centers are adjusted to avoid cutter interference for the 6 kinds of avoidance types. And then, the generative subsequent paths are sequenced to determine the second step cutter paths for the next uncut volume. For the 2 kinds of test models with convex and concave surface region, the implemented software algorithm is evaluated by investigating the residual swelling of uncut volume for each machining step.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.439-444
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• 2004

A new efficient intelligent machining strategy named the Steepest Directed Tree method is presented in this study, which makes surface model discrete with triangulation meshes and the cutter paths track along the tree directions. In order to formulate these algorithms practically, it is deduced the multi-stage machining approach of uncut volume caused by cutter gouging in the course of milling using flat end mill. It is systematized the checking process the cutter interference by grouping the 6 kinds of gouging types, which yields the environment of connectivity data lists including CL-data, and then the multi-stage machining strategy, that minimizes uncut area by continuously sequencing the generative subsequent CL-paths, is shamed to determine the second tool path for the next uncut area and to compose the operating multi-stage cutting processes. The completed machining system of curved surfaces is evaluated by testing the practical machining experiments which have various kinds of shape conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.6
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• pp.447-451
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• 2004

This study was conducted to establish the proper techniques of the recirculating wick hydroponics for safe seed tuber proliferation of potatoes (Solanum tuberosum L. CV. Dejima). To achieve these, several intact tubers (5, 10 and 20 g) and cut seed-pieces (two or four) were treated in wick hydroponic system beds. A polystyrene box (31cm in width, 20cm in height, 51cm in length, and $0.031m^3$ in volume) was placed on a styrofoam hox. Eight wicks $(width\;1.5cm\;{\times}\;length\;40cm) $ were put into each polystyrene hox and the boxes were filled with perlite + peatmoss (1 : 2, v/v) medium. Top fresh weight per plant increased with increasing the tuber size from 10 to 30g/tuber. As the tuber size increases from 10 to 30 g/tuher in case of uncut tuber, the marketable tuber (>5g) production per plant increased from 83.8 to 141.8 g/plant and the marketable tuber (>5g) production per plant of cut tuber was slightly higher than that of uncut treatment. Total tuber yield ranged from 4.16 to $6.56kg/m^2$ and the percentage of seed tubers was greater than $97\%$ for all treatments. These results indicate that seed tuber should be cut to produce large tuber $(\geq10g)$ in the recirculating wick hydroponic system.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.438-445
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• 1999

The concentrations of some ions ($NO{_3}^-$, $Ca^{2+}$, $Mg^{2+}$, $NH{_4}^+$) in soil solution collected by zero tension lysimeter in mature Pinus rigida plantations in Goksung, Jeonranam-do were measured at two soil depths (10cm and 30cm) following various levels of cutting intensity treatment (uncut, $6m{\times}50m$, $10m{\times}50m$, $20m{\times}50m$ strip crearcutting) three times (July 6. July 30, and August 4) between June 20 and August 4 1998. The ion concentrations in the soil solution were significantly different among sampling times, while the concentrations were not different among cutting levels or sampling depths. The ion concentrations in the soil solution decreased in the order of $NO{_3}^-$ > $Ca^{2+}$ > $Mg^{2+}$ > $NH{_4}^+$ and the mean concentration was 3.60mg/L for $NO{_3}^-$, 1.7mg/L for $Ca^{2+}$, 0.5mg/L for $Mg^{2+}$, and 0.04mg/L for $NH{_4}^+$ respectively. These ion concentrations except for $NH{_4}^+$ ion were negatively correlated with the volume of collected soil solutions (r=-0.31~-0.41). The results suggest that the change of nutrient concentrations in the soil solution collected from the P. rigida plantations was related to the temporal input patterns of precipitation rather than the cutting intensity.