• Journal of The Korean Society of Grassland and Forage Science
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• v.35 no.2
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• pp.119-124
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• 2015

In this study, we sought to evaluate the growth characteristics and seed productivities of domestic tall fescue that were cultivated with differing combinations of drill widths and nitrogen-application rates in early spring; the examination was conducted at the National Institute of Animal Science, RDA, from 2013 to 2014. The main plots were three widths of 15 cm, 30 cm, and 45 cm, and the subplots were subject to nitrogen-application rates in early spring of 45 kg/ha, 90 kg/ha, 135 kg/ha, and 180 kg/ha. The growth and development characteristics did not vary by treatment in terms of drill width and early-spring nitrogen application. Tall fescue Purumi showed a stable seed productivity of two tons or greater when the drill width was set at 15 cm and 90 kg/ha of nitrogen was applied in early spring. The narrower the drill width, the greater the numbers of both the ears and seeds, while the length of the ear was longer when the drill width was wider. Regarding the influence of the drill width and early-spring nitrogen application on the productivity of seed-producing straw, the dry matter productivity was higher when the drill width was narrower; however, no particular trend was observed with respect to different amounts of fertilizer. The average production amount of the first round of straw after seed gathering was 6,920 kg/ha. The second round produced an average 8,134 kg/ha of dry matter.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.3
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• pp.221-226
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• 2002

The effects of drill widths and nitrogen application levels on the growth characteristics and seed productivity of Italian ryegrasss(Lolium multiflorum Lam.) were evaluated. The experimental design was a split-plot arrangement with three replications. The main-plots were three drill widths of 15, 30 and 45cm, and subplots were three nitrogen application rates of 50, 75 and 100 kg/㏊ in early spring. Among the growth characteristics, lodging tolerance appeared to be highest in the treatment including 45cm of drill width and 50kg/㏊ of nitrogen application compared to other treatments. The numbers of stem per one square meter tended to be increased more in drill width of 15cm than in that of 30 or 45cm, but other growth characteristics were similar among treatments. In seed yield components, the numbers of spike per one square meter were getting increased according as drill width was narrower, but spike length and 1,000 seed weight were longer and heavier. respectively. The rate of ripened pains was highest in treatment including 30cm of drill width and 50kg/㏊ of nitrogen application. Maximum seed yield was also obtained in same treatment.

• Clinics in Shoulder and Elbow
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• v.13 no.1
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• pp.72-78
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• 2010

Purpose: Too develop a flexible drill device that can be inserted into the shoulder joint so that arthroscopic transosseous suture repair for Bankart lesion is possible. Materials and Methods: We created a device composed of a flexible drill unit and a guide pipe unit. The flexible drill unit was made of flexible multifilament wires (1.2 mm in diameter) that was twisted into one cord so that it can flex in any direction and a drill bit (1.2 mm in diameter) that is attached onto one end of the flexible wire. The guide pipe unit was a 150 mm long metal pipe (2.0 mm in inner diameter and 3.0 mm in outer diameter), with one end bent to 30 degrees. The flexible drill set was inserted into the shoulder joint through the posterior portal of the joint. The guide pipe component was placed onto the medial wall of the glenoid so that the pipe was placed 5 mm posterior to the margin of the anterior glenoid rim. The flexible drill was driven through the glenoid by the power drill so that holes were made in the glenoid. A non- absorbable suture was passed through the hole. Tying of a sliding knot tying was accomplished over the capsule and labrum after making a stitch through the capsule and labrum with a suture hook loaded with suture passer. The same procedures were done at the 2 and 4 O'Clock positions of the glenoid. Results: Five cases with Bankart lesion received arthroscopic transosseous repair with our flexible drill device. There were no intraoperative problems. Neither redislocation nor subluxation was reported at final follow-up. Conclusion: Arthroscopic transosseous suture repair without suture anchors and easy tying of a sliding knot are possible with a flexible drill set.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.713-714
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• 2012

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.42-42
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• 2017

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.189-190
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1009-1010
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• 2011

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.1
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• pp.49-54
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• 2000

A field experiment was carried out to determine the effects of seeding methods and rates on the growth characteristics, forage yield and nutritive value of sorghum X sudangrass hybrid (Sorghum bicolor (L.) Moench, cv. Pioneer 988) grown under application of animal manure in 1995. The application amount of animal manure were 40MT in cattle manure, 30MTha in swine and poultry manure. The methods and rates of seeding treated in this study were drill of 30kg, and broadcast of 30, 60 and 100kgha of seeding rates. The plant height was 180cm, 191cm and 204cm in cattle, swine and poultry manure, respectively. Plant height in the plot of drill was higher by about 15cm than those of broadcast plots. The dry matter(DM) yield was 7.73, 8.87 and 9.80MTha in cattle, swine and poultry manure, respectively. A significant higher forage yield was produced in the plot of drill, compared with broadcast(Pc0.05). DM yields in broadcast of 60kg and lOOkg of seeding rates were higher than that of 30kg of seeding rate of broadcast. However, no significant difference in forage yield was found between 60kg and IOOkg of seeding rates. The average DM yield was 11.16, 6.94, 8.26 and 8.83MTIha in drill(30kg), broadcast 30, 60 and 100kgIMT of seeding rates, respectively. The nutritive value of sorghum x sudangrass hybrid was very similar among treatments. The crude protein yields were 1,010kg in cattle manure, 1,180kg in swine manure, and 1,592kg in poultry manure. The protein yield was significantly high in the plot of drill. In conclusion, seeding by drill was recommended for forage production and protein yield of sorghumxsudangrass hybrid, and proper seeding rates were 30kg in drill and 60kg in broadcast. (Key words : Sorghumxsudangrass hybrid, Seeding rate, Seeding method, Forage yield, Nutritive value, Animal manure)

• Interaction and multiscale mechanics
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• v.4 no.4
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• pp.291-311
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• 2011

To simulate the self excited torsional vibrations of rotating drill strings (DSs) in vertical bore-holes, the nonlinear wave models of homogeneous and sectional torsional pendulums are formulated. The stated problem is shown to be of singularly perturbed type because the coefficient appearing before the second derivative of the constitutive nonlinear differential equation is small. The diapasons ${\omega}_b\leq{\omega}\leq{\omega}_l$ of angular velocity ${\omega}$ of the DS rotation are found, where the torsional auto-oscillations (of limit cycles) of the DS bit are generated. The variation of the limit cycle states, i.e. birth (${\omega}={\omega}_b$), evolution (${\omega}_b<{\omega}<{\omega}_l$) and loss (${\omega}={\omega}_l$), with the increase in angular velocity ${\omega}$ is analyzed. It is observed that firstly, at birth state of bifurcation of the limit cycle, the auto-oscillation generated proceeds in the regime of fast and slow motions (multiscale motion) with very small amplitude and it has a relaxation mode with nearly discontinuous angular velocities of elastic twisting. The vibration amplitude increases as ${\omega}$ increases, and then it decreases as ${\omega}$ approaches ${\omega}_l$. Sectional drill strings are also considered, and the conditions of the solution at the point of the upper and lower section joints are deduced. Besides, the peculiarities of the auto-oscillations of the sectional DSs are discussed.

• Geomechanics and Engineering
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• v.8 no.4
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• pp.477-493
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• 2015

In rock drilling, the most important characteristic to clarify is the wear of the drill bits. The reason that the rock drill bits fail with time is wear. In dry sliding contact adhesive wear deteriorates the materials in contact, quickly, and is the result of shear fracture in the momentary contact joins between the surfaces. This paper aims at presenting an overview of the assessment of WC/Co cemented carbide (CC) tricone bit in rotary drilling. To study wear of these bits, two approaches have been used in this research. Firstly, the new bits were weighted before they mounted on the drill rigs and also after completion their useful life to obtain bit weight loss percentage. The characteristics of the rock types drilled by using such this bit were measured, simultaneously. Alternatively, to measure contact wear, namely, matrix wear a micrometer has been used with a resolution of 0.02 mm at different direction on the tricone bits. Equivalent quartz content (EQC), net quartz content (QC), muscovite content (Mu), coarseness index (CI) of drill cuttings and compressive strength of rocks (UCS) were obtained along with thin sections to investigate mineralogical properties in detail. The correlation between effective parameters and bit wear were obtained as result of this study. It was observed that UCS shows no significant correlation with bit wear. By increasing CI and cutting size of rocks wear of bit increases.