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Current nitrogen management practices for most crops consist of a single application of a uniform rate of N fertilizer over whole fields and, frequently, whole farms. These practices contrast sharply [...]

Ductile materials such as AISI1008 low carbon steel characteristically exhibit poor chip breaking in conventional machining practices. This paper presents an environmentally clean cryogenic machining process which improves the breakability of AISI1008 chips by lowering the chip temperature to its embrittlement temperature. In this study, the brittle-ductile transition temperature of AISI1008 was experimentally determined to be between -60 [degrees] C and -120 [degrees] C. The discussion is focused on whether the chip can reach the embrittlement temperature before it hits an obstacle. A finite element simulation predicted the chip temperatures under various cutting conditions. Liquid nitrogen (LN2) was used to prechill the workpiece cryogenically. The results from the cutting tests indicate a significant improvement in chip breakability for different feeds and speeds by using this cooling technique. However, the effectiveness of cryogenetically prechilling the workpiece was found to be heavily dependent on cutting speed.

A preemptive diagnostic system has been developed to detect minor machine failures before machine breakdown for a computer controlled robotic drilling end-effector. By using the Dynamic Data System (DDS) approach, a set of discrete time series data taken from the continuous vibration signal of the machine is analyzed to detect machine failure and to distinguish failures due to the spindle, gears, air motors, and ball bearings of the machine drive system. Experiments validate that the proposed diagnostic method can identify spindle, air motors, gear, and bearing defects in the Robotic Drilling Unit.

The larval development of Euphasia (E) pacifica is examined and compared with that undergone by Euphasia nana larvae. E pacifica larvae were found to be smaller compared with E nana larvae during Calyptopis III to Furcilia II stages. In the successive stages, however, E pacifica larvae became larger than their counterparts. During Calyptopis III, geographical differences in body size were observed. The 5''6 tp 5''1 furcilia forms of the E pacifica population in the Yellow Sea were found to undergo segmentation of antenal endopods. It was suggested that E pacifica goes through six furcilia stages, instead of the seven proposed by other studies.

Previously, we have shown that the transition position shift in a perpendicular recording medium with a recording layer and a soft underlayer (SUL) is one of the major noise sources in high-density recording when abrupt single pole head field is applied. In this paper, we have considered a head rise time calculated from micromagnetic calculation for three different damping constants of pole tip. Also, in order to reduce the transition position shift, a modified medium with a synthetic antiferromagnetically coupled (SAFC) SUL was investigated. The SAFC-SUL was assumed to the 20-nm-thick top SUL with Ms of 800 emu/cc and the 80-nm-thick bottom-SUL with magnetization saturation (Ms) of 1200 emu/cc separated by a 0.6 nm Ru layer. The media with SAFC-SUL showed lower noise and higher signal-to-noise ration than the media with conventional SUL. The lower noise in the SAFC-SUL seems to be associated with suppressed vortex formation in the SUL by synthetic antiferromagnetic coupling in the SUL. Index Terms--Antiferromagnetically coupled soft underlayer (SUL), micromagnetic simulation, noise, perpendicular magnetic recording.

The magnetic dynamics of a total recording system composed of a single pole head and a perpendicular recording medium with a soft underlayer was performed by a three-dimensional micromagnetic model. In this paper, the effect of the magnetic damping constant of the soft underlayer (SUL) on the signal-to-noise ration (SNR) was systematically studied for the case of abrupt change in head field. For this purpose, the different damping constants ([alpha]) of 1.0, 0.1, 0.03, and 0.01 were studied in a conventional SUL. In all cases, SNR rapidly decreased with decreasing [alpha] of SUL. The longer range magnetic fluctuation in the SUL for smaller damping constant affects the shift of the transition region of the bits more. For comparison, we have shown SNR for the same media with a head field rise time was considered. Index Terms--Damping constant, micromagnetic simulation, perpendicular magnetic recording, soft underlayer (SUL).

It was found that a reduction in [M.sub.r]t can be obtained in the new antiferromagnetically coupled (AFC) medium with a CrMo spacer layer due to antiferromagnetic (AF) coupling, which is similar to the conventional AFC medium with a Ru spacer layer. From the results of [DELTA]M and magnetic force microscopy (MFM), it was found that the intergranular exchange coupling decreases when CrMo is used as a spacer layer. Micromagnetic simulations of [DELTA]M and MFM analyses gave consistent results with experiment, i.e., 1) AFC media with higher intergranular exchange coupling constant have larger magnetic cluster and higher [DELTA]M peak and 2) the media with higher AF coupling constant have smaller magnetic cluster and smaller [DELTA]M. In this paper, we propose that the media noise of the AFC media with a CrMo spacer layer may be improved by a reduction in the magnetic duster size, due to the decrease of the intergranular exchange coupling between magnetic grains. Index Terms--[DELTA]M analysis, antiferromagnetically coupled (AFC) media, antiferromagnetic coupling, interlayer diffusion, micromagnetic simulation.

A study was conducted to analyze the effects of the Cr75Ti25/CoTi bilayer on magnetic and crystallographic characteristics in CoCrPt longitudinal recording media. Films were deposited on glass substrates that were heated at 250 degrees C using the dc magnetron sputtering technique. Results indicated an improvement of the coercivity which correlates with an increase of magnetic decoupling effect through the chromium segregation at the grain boundaries.

The magnetic properties and thermal stability of the antiferrometically coupled (AFC) medium with a pure Cr or CrMo spacer layer instead of a Ru spacer layer are determined. Comparing the switching field distribution and DELTA M of the AFC medium with those of the conventional AFC medium, it is believed that the intergranular exchange coupling decreases when a CrMo is used as a space layer.

The effects of CoCrPtTa and CoCrPtB magnetic intermediate layers (ILs) on the magnetic properties and read/write performance of CoCrPt/soft magnetic layer perpendicular recording media were examined. The improved performance of the media with ILs can be attributed to the reduction of grain size of the magnetic layer and weakening of the intergranular interaction between grains by insertion of the IL.

Provides information on a study which investigated the effects of chromium...titanium.../cobalt-titanium bilayer on the magnetic and crystallographic properties in cobalt-chromium-platinum longitudinal recording media. Experimental method; Results and discussion.