Water-filled Glass Research Articles

Water uptake through sweet cherry (Prunus avium L.) fruit pedicels: Influence of fruit surface water status and intact fruit skin

A modified potometer consisting of a water-filled glass tube mounted in parallel with a metric scale and connected to a fruit was used to study water uptake into detached fruits of sweet cherry. Results describing quantities of imported water from some introductory studies were in the same range as in previously published studies conducted with alternative methods. Water uptake was measured in fruits of four cultivars kept in air of approximately 50±5% RH followed by immersion in water 1–2 h into the experimental period. This caused a significant decrease in water uptake. However, the fruits continued to accumulate water at a reduced rate. When the fruits were dried, the water uptake immediately increased to the same level as before the immersion in water. The fruit skin of two cultivars was exposed to normal air after being ruptured with four shallow cuts to simulate cuticular fractures or shallow cracks. These two treatments did not give statistically different water uptake through the pedicel, although there was a tendency to an increased rate of water uptake in fruits with ruptured fruit skin.

Cognitive influence on motor control in reaching.

The purpose of this study was to assess the effects of objects with different attributes on motor control in the act of reaching for them. Much about reaching has been studied from the point of view of spatial relations between objects and subjects, and kinematic approaches have played an important role in this field. Recently, some researchers have proposed that factors other than spatial relations characterize reaching. Therefore, we focused on reaching for an empty glass (empty condition) and a water-filled glass (filled condition) where the positions of the glasses were the same to examine the importance of the objects when reaching for them. Eight young adults participated. We translated the position of the index finger into X-Y-Z coordinate values and examined movement time, length of trajectory, and velocity between the empty and filled conditions. It took longer to reach for an empty than a filled glass, and the filled condition showed a longer trajectory and slower velocity than the empty condition. This indicated that objects with different attributes influenced the reaching and that the role of cognition of attributes is important in the act of reaching.

The removal of bacterial biofilm from water-filled tubes using axially propagated ultrasound

Axially propagated ultrasound (APU) has been used to remove mineralized Proteus mirabilis biofilms from water-filled glass tubes. Pulses (30 s) of ultrasound at frequencies ranging from 350 to 20 kHz were applied to one end of the tubes and the extent of biofilm removal was assessed by infra-red absorptiometry. The removal of biofilm from 7 cm tubes by two 30 s pulses of APU at 150 kHz (54·8%) was comparable to that (60·9%) achieved by sonication at 33 kHz in a conventional sonic cleaning bath. In 50 cm tubes, three 30 s pulses of APU from the 20 kHz transducer removed 87·5% of the biofilm. The equivalent results for APU at 150 kHz and 350 kHz were 66·8% and 31·3%, respectively. These observations suggest that the axial propagation of ultrasound along lengths of water-filled tubing offers the prospect of on-line cleaning of systems such as heat-exchanger pipework.

Mechanisms of intraocular photodisruption with picosecond and nanosecond laser pulses.

Nd:YAG laser photodisruption with nanosecond (ns) pulses is an established method for intraocular surgery. In order to assess whether an increased precision can be achieved by the use of picosecond (ps) pulses, the plasma size, the shock wave characteristics, and the cavitation bubble expansion after optical breakdown with ps- and ns-laser pulses were investigated by time-resolved photography and acoustic measurements. Nd:YAG laser pulses with a duration of 30 ps and 6 ns, respectively, were focused into a water-filled glass cuvette. Frequency doubled light from the same laser pulses was optically delayed between 2 ns and 136 ns and used as illumination light source for photography. Since the individual events were well reproducible, the shock wave and bubble wall position could be determined as a function of time. From the slope of these r(t) curves, the shock wave and bubble wall velocities were determined, and the shock wave pressure was calculated from the shock velocity. The plasma size at various laser pulse energies was measured from photographs of the plasma radiation. The breakdown thresholds at 30 ps and 6 ns pulse duration were found to be 15 microJ and 200 microJ, respectively. At threshold, ps-plasmas are shorter than ns-plasmas, but at the same pulse energy they are always approximately 2.5 times longer. The initial shock pressures were 17 kbar after ps-pulses with an energy of 50 microJ, and 21 kbar after 1 mJ ns-pulses. The pressure amplitude decayed much faster after the ps-pulses. The maximum expansion velocity of the cavitation bubble was 350 m/s after a 50 microJ ps-pulse, but 1,600 m/s after a 1 mJ ns-pulse. The side effects of intraocular microsurgery associated with shock wave emission and cavitation bubble expansion can be considerably reduced by the use of ps-pulses, and new applications of photodisruption may become possible.

Fully hydrated laumontite: A structure study by flat-plate and capillary powder diffraction techniques

The structure refinement of laumontite [Ca 4Si 16Al 48·O 48·18 H 2O; Z = 1, CuKα radiation; T = 295 K; cell a = 14.845(9), b = 13.167(2), c = 7.5414 (8) A ̊ ; β = 110.34(2)°, C2/m, D x = 2.306, M r = 1917.80] was completed from X-ray powder data obtained with two different techniques using a fully hydrous sample. Data collection was performed using (a) a mylar-sealed flat-plate holder with the sample submerged into water, Bragg-Brentano geometry, and a conventional two-circle Philips goniometer, and (b) the sample in a water-filled glass capillary, Debye-Scherrer geometry, and an INEL CPS120 position sensitive detector. The results obtained by Rietveld refinement of the two independent data sets are compared and found to be in full agreement. The water content of fully hydrated laumontite is shown to be 18.0 water molecules per cell. The excess water molecules present in laumontite with respect to leonhardite completely stabilize a 7-coordinated geometry for the Ca atoms in the channels. This study shows that reliable structural information not accessible with other techniques can be extracted by Rietveld refinement of powder data collected with unconventional experimental geometries and sample preparation techniques.

The application of total vertical projections for the unbiased estimation of the length of blood vessels and other structures by magnetic resonance imaging

A new stereological method has recently been developed to estimate the total length of a bounded curve in 3D from a sample of projections about a vertical axis. Unlike other methods based on serial section reconstructions, the new method is unbiased (i.e., it has zero systematic error). A basic requirement, not difficult to fulfill in many cases, is that the masking of one structure by another is not appreciable. The application of the new method to real curvilinear structures using a clinical magnetic resonance (MR) imager is illustrated. The first structure measured was a twisted water-filled glass tube of known length. The accuracy of the method was assessed: With six vertical projections, the tube length was measured to within 2% of the true value. The second example was a living bonsai tree, and the third was a clinical application of MR angiography. The possibility of applying the method to other scientific disciplines, for example, the monitoring of plant root growth, is discussed.

Analytical and experimental study of steady-state convection in a double-loop thermosyphon

Steady-state natural convection in a toroidal loop with a heated diametrical branch and cooled side branches is studied. The loop is rotated to vary the tilt angle of the diametral branch. A one-dimensional analysis provides the fluid velocities and temperature distributions in the loop. The effects of axial conduction are examined. With increasing tilt from the vertical, the fluid in the lower side branch slows down and reverses. The flow through the central branch increases and the main return path is through the upper side branch. For small tilt angles around the horizontal, multiple steady states exist. Comparison experiments on a water-filled glass loop are in qualitative agreement with the analysis and multiple steady states are observed.