Lapping Rate Research Articles

Precision fabrication of D-shaped single-mode optical fibers by in situ monitoring

A technique has been developed to locally remove, over a distance of several millimeters of fiber length, the cladding layer of single-mode (at the 1300 nm wavelength) optical fibers with 1 /spl mu/m depth precision by use of mechanical lapping and in situ optical transmission monitoring. A cylinder lap dressed with diamond is used to perform high-pressure mechanical lapping. The in situ monitoring technique is based on the specific different attenuations exhibited by higher order propagating modes (for 633 nm light) as the cylinder penetrates into the fiber. Advantages include relatively rapid overall processing, high lapping rate, good optical surface quality, and 1 /spl mu/m precision. Experimental results are presented and analyzed by an approximate geometrical-optics model. >

Determinants of left ventricular filling dynamics: alteration in the Doppler-derived transmitral filling profile with progressive impairment of cardiac function in a dog preparation.

To clarify the factors determining transmitral filling, left ventricular and atrial pressures (LVP and LAP) and Doppler-derived diastolic indices were analysed in six anaesthetized dogs at various right atrial pacing rates during dextran infusion. The relationship of the late to early diastolic peak velocity ratio (A/E ratio) to end-diastolic LVP (LVEDP) showed a quadratic curve concave to the LVEDP axis in five animals (r2 = 0.320-0.588). An elevation in LVEDP up to 25 mmHg accompanied an increase in A/E ratio (ascending limb), and further LVEDP elevation caused its inverse decline (descending limb). Multiple regression analysis indicated that A/E ratio correlated positively with maximal LVP, a-wave LAP and heart rate, and negatively with v-wave LAP in both limbs. The time constant of isovolumic LVP decline, which was prolonged as LVEDP was elevated, was a positive correlate of A/E ratio in the ascending limb, but lost its influence on A/E ratio in the descending limb. An elevation in v-wave LAP must have masked the expected effect of left ventricular relaxation abnormality on A/E ratio in this limb. Thus, the transmitral filling profile did not alter unidirectionally, but returned to that seen before volume loading, with a simultaneous progressive impairment of cardiac function.

Adjustment to intermittent access in rats drinking saccharin: II. Adjustment of lapping rate

Hungry rats were permitted to drink saccharin under conditions in which (a) the drinking spout was available continuously, or (b) it was withdrawn during alternate 30-sec periods. Rats adjust to such constraint by increasing their integrated lap rate (laps/min). We show that one way in which they do this is to lap at a higher rate within bursts of lapping. This faster lapping is not an artifact of forced interruptions and resumptions. It cannot only be maintained over a drinking session, but also initiated midway through the session if restricted access is imposed then. Therefore, the period of the lapping cycle can be adjusted, within limits, in response to situational constraints on access to the fluid.

Some determinants of the time course of saccharin ingestion in hungry rats

In rats that are food- but not water-deprived, a saccharin “meal” is characterized by a progressive decrease in lap rate as the bout progresses. However, saccharin does not trigger a fixed rate of lapping at any point in the sequence. When rats have only intermittent access to saccharin early in the session, they increase their rates of lapping so that, within each few minutes, the amount of lapping (or some correlate such as volume drunk) is held constant. This happens over a wide range of restriction conditions. And if compensation cannot occur during a period of constraint, then it occurs ofterward, promptly and precisely. When constraint is withdrawn, rats drink amounts such that the total amount of drinking (or its correlate), through that point in the ingestive bout, is defended. These findings imply that the controlling system includes (1) an integrator that keeps track of the amount of drinking that has occurred, even across interruptions; and (2) a short-term feedback loop that operates minute by minute within the bout. This loop regulates, not the rate of lapping to be emitted, but the amount of lapping to be done (or its correlate); Thus the decline in responsiveness to saccharin as drinking progresses reflects a depression of this regulated value, not of lap rate per se.

Saccharin drinking by hungry rats: Adjustment to constraints

In food-deprived rats, rate of lapping at a saccharin cylinder declines progressively over a session. The decline is unaffected, within limits, by restricted access: Whether the cylinder is available continuously, or only during alternate 30-sec intervals, the rat adjusts its momentary lap rate so that the amount of lapping within each 5-min period remains the same. It is as if the rat specifies over each brief period how much ingestive behavior is to occur, and then adjusts its lap rate so that actual ingestive behavior matches the specification. The specification in turn moves down as the drinking bout progresses.

Individual consistency and modifiability of lapping rates in rats: A new look at the variance-invariance question

Lapping rates were recorded from water-deprived rats over 3-week periods when they were young adults and again, 9.4 months later, when they were middle-aged. Test-retest correlation coefficients of 0.95, that were obtained for lapping rates recorded as long as a week apart, reflect extremely consistent frequency control, which is in line with the proposal by Wiesenfeld et al. (1977) that licking/lapping is under control of a hypoglossal oscillator. These high test-retest correlations were obtained both in young adulthood and again, later in middle-aged rats. However, correlations across the 9.4 months were close to zero, although mean water lapping rate did not change. Our data indicate that the effects of aging on lap rate were of two kinds. (1) Producing randomized shifts in the lapping rate of individual rats over long periods, with conservation of the stable mean rate, and (2) accentuating the tendency for reduction in the lapping rate for the last 50 laps compared with that of the first 50. It also appeared that the relevance of the fluid being lapped, in relation to water deprivation, was another important variable in determining the lapping rate. These and other data are considered in relation to the variance-invariance issue.

Effects of nectar concentration and flower depth on flower handling efficiency of bumble bees

Fluid viscosity only affected ingestion rates of bumble bees (Bombus) for solutions greater than 35-40% sucrose (mass of solute per mass of solution). This contrasts with previously published models based on fluid dynamics which predicted continuous depression of ingestion rates with increasing viscosity. Individual bees maintained constant lapping rates regardless of sucrose concentration (up to at least 70%). The decline in ingestion rates at higher concentrations apparently resulted from the tongue not contacting liquid long enough to become saturated due to reduced capillary flow. Increasing flower depth similarly decreased the volume of liquid ingested per lap, and did not affect lapping rate. Morphologically dissimilar bees drank at different rates because glossa length affects lapping rate and volume ingested per lap, and body mass affects lapping rate. An additional species-specific component to lapping rate also influenced ingestion rates. Deviations from a regression model derived to explain ingestion rates as a function of glossa length, body mass, flower depth and liquid viscosity suggest mechanistic and behavioralaspects to flower probing time. Because of the relation between ingestion rate and liquid viscosity, the sucrose concentration maximizing a bee's rate of net energy uptake should lie between 50-65%, depending primarily on specific conditions of nectar volume, inflorescence size and flight time between inflorescences.

ジルコンチタン酸鉛磁器の生産ラッピング

Production lapping of lead zirconate-titanate ceramics are dealt with lapping rate, parallelism, yield and machining time including cutting-off time, since ceramics are machined as planeparallel, slender, thin plates in using for relay switches. The results obtained are as follows : (1) The order in lapping rate is A (no additive) >D (added Cr) >C (added Nb) >B (added Fe). Strong specimen C has a yield of 95%. (2) The difference in plate thickness within 10μ and the parallelism of 2μ are obtained from plane-parallel lapping, where the motion of specimens is restricted in carriers. (3) The concentration of lapping vehicle influences on lapping rate only by a factor of 5%. Supplying vehicle at a rate of 150 cc/min is desirable for preventing from breakage of plates. (4) Cut-off thickness is chosen as 0.3 mm regardless of the kind of ceramics. The whole machining time in lapping plates of 0.3 mm thick to 0.2 mm thick is shortened by a factor of about 40% than in lapping plates of 0.5 mm thick.