Multiple Exposure Photographs Research Articles

Aurelijos Maknytės paroda „Tėvų kambarys“ kaip laikovaizdis

The concept of time-image ( image temps ) coined by Gilles Deleuze could be applied to analysis of works of art that juxtapose objects from different periods of time and combine them into spatial installation-projects. Such exhibitions are designed for the visitor to create their final and ideal version, and have to be ‘performed’. This leads to the obliteration of clear concepts as well as to the process of self-creation. Agnė Narusytė uses the concept of time-image as well as Erika Fischer-Lichte’s theory of performative aesthetics in her phenomenological analysis of the exhibition Parents’ Room , which was installed by the Lithuanian contemporary artist Aurelija Maknytė at the gallery Artifex in 2015. In Parents’ Room , Maknytė created layers of different periods and places as experienced by different people: a tailor who wrote letters to her daughter from 1965 to 1990, Maknytė’s parents, already dead, and herself in two roles: that of a daughter and of a step-mother. The artist does not mask the separateness of the layers; she even reveals the sources: fragments of a family’s life, printed materials she collects, artefacts made for different purposes (soviet folded tables for celebrations, shoes for funerals, a sewing machine, sewing patterns cut from soviet newspapers), her own works (an artist’s book compiling the tailor’s letters, Father’s Act created in 2001 from her father’s autopsy report and The Role – an appropriated film by Rūta Simkaitienė, The Gardener goes to the Cemetery (1992) where Maknytė played a step-mother). Both comic and macabre, the stories of other people’s lives are condensed in the exhibits installed in the three spaces of the gallery. Like in multiple exposure photographs, the exhibition connects realities that ‘have no clue’ about each other but are interlinked through accidental coincidences, invisible to them, but planned by the artist. The viewer becomes an all-seeing privileged connoisseur from the ‘future’ who gets also involved into the exhibition’s narrative, thus forming an additional layer.

Motility and morphology of human spermatozoa in split ejaculates.

Sperm concentration and four motility characteristics (per cent motile spermatozoa, average velocity, average straight line approach and average speed constancy) were determined in three fractions of human split ejaculated from healthy volunteers. A semi-automatic analysis technique was used to determine sperm parameters from multiple exposure photographs (MEP). Sperm concentration and percentage motility were significantly higher in the first fraction as compared to the third fraction of split ejaculates. The average spermatozoal velocity, average speed constancy and average straight line approach were the same in all fractions. Differences in the percentage of motile spermatozoa were also found after collection of split ejaculates in culture medium. This phenomenon may have been caused by differences in sperm morphology. Significantly more normal spermatozoa were present in the first fractions of 19 split ejaculates as compared to the last fractions.

Evaluation of high dynamic range photography as a luminance data acquisition system

In this paper, the potential, limitations and applicability of the High Dynamic Range (HDR) photography technique are evaluated as a luminance mapping tool. Multiple exposure photographs of static scenes were taken with a commercially available digital camera to capture the wide luminance variation within the scenes. The camera response function was computationally derived by using Photosphere software, and was used to fuse the multiple photographs into an HDR image. The vignetting effects and point spread function of the camera and lens system were determined. Laboratory and field studies showed that the pixel values in the HDR photographs correspond to the physical quantity of luminance with reasonable precision and repeatability.

The vortex ring velocity resulting from an impacting water drop

Experimental observations are reported on the evolution of a vortex ring for the first 70 ms after it is created by the impact of a dyed water drop upon a pool of clear water. The 2.6 mm diameter drops were released from two heights. The drops impacted the pool with Weber numbers of 23.2 and 16.6 and Froude numbers of 25.2 and 18.0. The Reynolds number of the resulting relaminarized vortex rings based on their diameter was in the range of 320 to 390. Precisely controlled multiple exposure photographs were used to measure the position and shape of the vortex ring versus time, and calculate velocity. It is proposed here that the appropriate time scale is the time it takes for the impact crater to reach its maximum depth. Excellent agreement was found when using this scaling to compare both the present data sets and that previously published for a larger drop.

IMAGING OF IMPINGING JET BREAKUP AND ATOMIZATION PROCESSES USING COPPER-VAPOR-LASER-SHEET-ILLUMINATED PHOTOGRAPHY

Observation of a like-on-like injector element in the near-injector region has been accomplished with laser-sheet- illuminated photography to investigate spray characteristics as a function of jet velocity and injector geometry. Short duration exposures from single laser pulses produced instantaneous pictures of the injection and subsequent breakup processes, while multiple-exposure photographs revealed a time-averaged representation of the spray. In addition to the four previously documented spray regimes, the data suggested inclusion of a higher Reynolds number regime in which the pre-impingement jets are fully turbulent and undergoing surface breakup. The equation of a conic section was used to map multiple-exposure photographs revealing the overall spray shape. Further examination of the higher Reynolds number regime using transparent injector pieces revealed the presence of a cavitating region within the orifice. Discharge coefficients were calculated and found to be relatively constant for each injector tested, regardless of the presence of cavitation. The orientation of the injector orifice created a stable cavitating region in which the phenomenon of hydraulic flip was not observed, but the enhanced turbulence level led to an onset of jet atomization prior to impingement.

IMAGING OF IMPINGING JET BREAKUP AND ATOMIZATION PROCESSES USING COPPER-VAPOR-LASER-SHEET-ILLUMINATED PHOTOGRAPHY

Observation of a like-on-like injector element in the near-injector region has been accomplished with laser-sheet- illuminated photography to investigate spray characteristics as a function of jet velocity and injector geometry. Short duration exposures from single laser pulses produced instantaneous pictures of the injection and subsequent breakup processes, while multiple-exposure photographs revealed a time-averaged representation of the spray. In addition to the four previously documented spray regimes, the data suggested inclusion of a higher Reynolds number regime in which the pre-impingement jets are fully turbulent and undergoing surface breakup. The equation of a conic section was used to map multiple-exposure photographs revealing the overall spray shape. Further examination of the higher Reynolds number regime using transparent injector pieces revealed the presence of a cavitating region within the orifice. Discharge coefficients were calculated and found to be relatively constant for each injector tested, regardless of the presence of cavitation. The orientation of the injector orifice created a stable cavitating region in which the phenomenon of hydraulic flip was not observed, but the enhanced turbulence level led to an onset of jet atomization prior to impingement.

Multiple-exposure photographic analysis of a motile spirochete.

The Leptospiraceae are thin spirochetes with a unique mode of motility. These spiral-shaped bacteria have internal periplasmic flagella that propel the cells in low-viscosity and gel-like high-viscosity media. A model of Leptospiraceae motility has been previously proposed that states that the subterminally attached periplasmic flagella rotate between the outer sheath and the helical protoplasmic cylinder. The shape of the cell ends and the direction of gyration of these ends are determined by the direction of rotation of the internal periplasmic flagella. Rotation of the periplasmic flagella in one direction causes that end to be spiral-shaped, and rotation in the other direction causes that end to be hook-shaped. One prediction of the model is that these right-handed spirochetes roll clockwise when swimming away from an observer. For maximum swimming efficiency, the model predicts that the sense of the spiral-shaped end is left-handed and gyrates counterclockwise. The present study presents direct evidence that the cell rolls clockwise (protoplasmic cylinder helix diameter = 0.24 micron; pitch = 0.69 micron), the ends gyrate counterclockwise, and the spiral-shaped end is left-handed (helix diameter = 0.6 micron; pitch = 2.7 microns)--as predicted by the model. The hook-shaped end appears approximately planar. The approach used was to illuminate stroboscopically cells slowed by Ficoll and analyze the resultant multiple-exposure photographs focused above and below the axis of the cell. The methodology used should be helpful in analyzing the motility of the larger and more complex spirochetes.

Some Rheological Properties of a Diluted Gelatin Aqueous Solution in the Turbulent Flow Region. I

The rolling ball method was used to study rheological properties of gelatin solution. The motion of a stainless steel ball in a slanting glass tube filled with the solution was observed. In order to attain turbulent flow, we chose the ball of 1.113 cm diameter and the tube of 1.650 cm diameter. The achievement of the turbulent flow condition was checked from the theoretical and experimental points of view.The terminal velocity of the ball in the 0.5% aqueous solution of gelatin exceeded that in water when the slope of tube exceeded 64°. Whether the ball was rolling or sliding in this region was examined by taking multiple exposure photographs, using the ball marked with a small piece of fluorescent adhesive tape. At the beginning the ball was rolling normally. Soon the sliding was combined with rolling, the rate of rotation gradually decreased, and then the rotation completely stopped. Finally, the ball rotated in reverse direction. Such behavior was never observed in pure water. The possible causes of this unique phenomenon were discussed. This may be one mode of appearance of the Toms effect of gelatin.

The role of photographic parameters in laser Speckle of particle image displacement velocimetry

The parameters involved in obtaining the multiple exposure photographs in the laser speckle velocimetry method (to record the light scattering by the seeding particles) were optimized. The effects of the type, concentration, and dimensions of the tracer, the exposure conditions (time between exposures, exposure time, and number of exposures), and the sensitivity and resolution of the film on the quality of the final results were investigated, photographing an experimental flow behind an impulsively started circular cylinder. The velocity data were acquired by digital processing of Young's fringes, produced by point-by-point scanning of a photographic negative. Using the optimal photographing conditions, the errors involved in the estimation of the fringe angle and spacing were of the order of 1 percent for the spacing and +/1 deg for the fringe orientation. The resulting accuracy in the velocity was of the order of 2-3 percent of the maximum velocity in the field.

Non-Gaussian statistics of speckle noise of Young's fringes in speckle velocimetry

In speckle velocimetry, Young's fringes observed during analysis of the multiple-exposure photographs of tracer particles seeding a fluid flow are embedded in a speckle noise that renders their analysis difficult. Some first- and second-order statistical properties of this speckle background are considered in this paper. A simple model shows that, because of the small and fluctuating number of scatterers contained in the probe beam, the intensity fluctuations are enhanced, leading to a contrast greater than one. The same model also shows that the speckle grains are not completely independent because of the existence of long-range intensity correlations.

Theoretical Modeling of Grip Firmness during Ball-Racket Impact

Abstract This study was undertaken to establish theoretical bases for the experimental results reported by Baker and Putnam (1979), and Walanabe, Ikegami and Miyashita (1979), concerning grip firmness on a tennis racket and its effect on the ratio of post- to pre-impact ball velocity. The model predicted that, for central impacts, there was no change in the ball velocity ratio when a regular tennis racket was tightly clamped at the grip or allowed to freely stand on its butt. To validate the model further, alterations were made to two parameters of the racket—a tennis racket was modified to increase the stiffness, and a racketball racket was used to simulate a shortened tennis racket. Multiple exposure photographs were taken of balls striking the center of the rackets under the two extremes of grip firmness. Measurements were taken from enlargements of these photographs in order to calculate the horizontal component of post- to pre-impact ball velocity. It was found that shortening the length and greatly ...

Tennis Racket and Ball Responses during Impact under Clamped and Freestanding Conditions

Abstract Selected responses of a tennis racket and ball during the impact phase were investigated in an attempt to establish the influence of grip firmness on ball velocity after impact. Two extreme conditions of grip firmness were considered: (a) when the grip of the racket was firmly clamped to a rigid metal support frame and (b) when the racket was allowed to stand freely on its butt with no other means of support. The study was conducted in two parts: 1. Three multiple-exposure photographs were taken of ball impacts on a variety of rackets with different constructions, flexibilities, string types, and string tensions under the two conditions of grip firmness. Measurements were taken from enlargements of these photographs in order to calculate the horizontal component of post- to pre-impact ball velocity. 2. A high-speed cinematographic analysis was conducted of one ball-racket impact under both conditions of grip firmness. It was found that the magnitude of the impulse applied by the racket to the bal...

Asymmetric waveforms in echinoderm sperm flagella.

1.Dark-field, multiple-exposure photographs of live spermatozoa of a number of echinoderms were analysed. 2. Bends develop at the base in pairs, as they do in flagella with symmetrical waveforms. However, the angles of these bends do not cancel, so that microtubular sliding-of up to over 50% of that associated with bend propagation-is transferred distally. This sliding implies that (a) microtubules are not rigidly cross-linked within straight regions, and (b) bends can propagate normally in spite of appreciable extrinsic microtubular sliding. 3. Both the sperm head and the asymmetry of the waveform appear to affect the swim path of a spermatozoon.

Form of developing bends in reactivated sperm flagella.

1. Dark-field, multiple-exposure photographs of reactivated tritonated sea urchin sperm flagella swimming under a variety of conditions were analysed. 2. The length, radius and subtended angle of bends increased during bend development. The pattern of development was essentially the same under all conditions observed. 3. The angles of the two bends nearest the base tend to increase at the same rate, cancelling one another, so that the development of new bends causes little if any net microtubular sliding. 4. The direction of microtubular sliding within a bend is initially in the same direction as that within the preceding bend, and reverses as the bend develops.

Flight Characteristics of Two Plume Moths, Alucita pentadacty/a L. and Orneodes hexadactyla L. (Microlepidoptera)

AbstractNorberg, R. Å. (Department of Zoology, University of Gothenburg, Göteborg, Sweden.) Flight characteristics of two plume moths, Alucita pentadactyla L. and Orneodes hexadactyla L. (Microlepidoptera). Zool. Scripta 1 (6): 241–246,1972.–Multiple exposure photographs of up to 100 exposures/sec were taken on two plume moth species in free, unrestrained flight, in order to determine approximate lift/drag ratios and other functional characteristics of their wings, which are of a remarkable structure for insects of this size. In Alucita the forewing is cleft in two fringed lobes, the hind‐wing in three, while in Orneodes both forewing and hindwing are deeply cleft in six very narrow, fringed lobes. Wing stroke frequencies are ca. 33 Hz in A. pentadactyla and ca. 40 Hz in O. hexadactyla. During both the downstroke and the upstroke the fringed wing lobes lie edge against edge, thus forming a continuous wing surface. The upstroke seems to contribute no useful forces in A. pentadactyla, possibly some propulsive force in O. hexadactyla. The wings are strongly supinated in the upstroke to minimize drag. From relative wind diagrams, lift/drag ratios of 1.1 and 1.4 (minimum values) can be read for A. pentadactyla and O. hexadactyla, respectively. It is thus clear that these species do not make more use of drag forces than of lift forces. However, in A. pentadactyla the drag force in the downstroke may be almost as large as the lift force. Since drag certainly is small in the upstroke, the drag force probably contributes significantly to useful forces for flight in A. pentadactyla. These plume moths operate at Reynolds numbers of ca. 700. Reynolds numbers are calculated for very small insects. It is obvious that the wings of the smallest insects must be operating at Reynolds numbers of about 1. The fringed wings of small insects are briefly discussed.

The initiation of flight in unrestrained locusts,Schistocerca gregaria

1. A technique is described for taking multiple exposure photographs of the first 100 msec of the jump of unrestrained and unstimulated locusts,Schistocerca gregaria (phasis gregaria) (Fig. 1). 2. Photographs were taken of locusts jumping under twelve different experimental conditions (Table 1). Eight features of the jump were measured (Table 2). 3. The direction of take-off is variable under all conditions. In intact locusts the mean take-off angle is approximately 45 ° but the mean increases significantly in all the groups of operated insects (Table 3). 4. The body angle at the moment of take-off is always variable but neither the mean nor the standard deviation of the performance changed significantly in different experimental groups. There is no correlation between the take-off angle and the body angle at the instant of take-off. 5. 70 msec after take-off a correlation develops between the body angle and the direction of motion in all the experimental groups except that in which the central nervous system is severed between the brain and the thoracic ganglia (Table 4). The correlation coefficient is always higher in the experimental groups which were exposed to a headwind. 6. Experiments using localised jets of air show that the increased correlation between the body angle and the direction of motion is not due to the passive aerodynamic effect of the air flowing over the body. The evidence suggests that the insect obtains information about the direction of the headwind and decisions about the form of the later stages of the jump and the timing of the onset of wing movements are made before the jump begins. 7. The rotation of the body in the plane of pitch during the first 100 msec of the jump is caused mainly by movements of the legs which alter the balance of the body. 8. The delay between the metathoracic tarsi leaving the ground and the start of visible wing movements is never constant and may be negative. The mean delay in certain experimental groups was found to be significantly different from the controls. Cutting the nerve cord anterior to the thoracic ganglia and destruction of the cephalic wind sensitive organs shortens the delay, but damage to the nervous system posterior to the thoracic ganglia has no effect (Table 5). 9. In both the intact and injured groups, the stimulus of an airstream caused a significant decrease in the mean latency of the flight response. There was no correlation between the degree of alignment of the body to its direction of motion and the latency of the flight response. 10. Cutting the nerve cord anterior to the thoracic ganglia and destruction of the cephalic wind sensitive organs also caused a significant increase in the period of the first wingbeat cycle but none of the other experimental conditions altered it (Table 6). 11. The timing of the beginning of visible wing movements did not correlate with any feature of the jump which was measured. 12. It is concluded that variation in the form of the jump is an inherent property of the system and may be due to mechanical instability as well as to variability in the neural program. The brain is involved in adapting the form of the jump so that less energy is wasted as drag before wing movements take over as the method of propulsion. It is suggested that the neural centres which control jumping and flight are mutually inhibitory and that the strength of the inhibition depends upon input from the rest of the nervous system.

Considerations on high peak powers from CO2and CO2- mixture lasers

A pulsed excitation was used to study high peak power generation in CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> and CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> -mixture flowing gas lasers. A rotating mirror was used as a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</tex> switch with a variable delay between excitation pulse and mirror alignment. A variation of the time delay and multiple-exposure photographs can permit a measure of the population inversion versus time to be photographed. High-voltage pulses were used with higher than usual gas pressures to generate peak powers of about 30 kW. Peak power was shown to be primarily dependent on CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> partial pressure in CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> -He and CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> -N <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> mixtures.

Observation of multiple scattering resonance effects in low energy electron diffraction studies of LiF, NaF and graphite

The predicted effects associated with the resonances that occur in a multiple scattering theory of electron diffraction by crystals 2) are (a) a peak in the 00 beam intensity at an electron energy below that of the lowest-energy resonance, and (b) minima in all beam intensities at the energy of each resonance. According to the theory for crystals made up of identical atom layers, with one atom per unit mesh in each layer, there is a resonance associated with the emergence of each diffracted beam parallel to the surface. The theory is extended to the case of two atoms per unit mesh in each layer. In specific applications to alkali halide (001) and graphite (0001) surfaces, it is shown that the theory leads to the same result as for the case of one atom per unit mesh-layer, except in that for alkali halides there is no resonance associated with the emergence of beams whose index sum is odd. The theory indicates that both the energy interval between the resonance and the emergence energy of the associated beam, and the energy interval between the resonance peak and the resonance, are approximately independent of beam orientation. It is proposed that an identification of resonance effects can be based on these properties. Sets of experimental 00 reflectivity curves, showing the effects of varying the primary beam orientation, are presented for NaF and graphite crystals. In each set of curves, and in the corresponding sets for LiF crystal 4), series of resonance peaks are identified on the basis of a correlation with the emergence energies of the relevant diffracted beams. It is shown that in the case of LiF crystal the resonance minimum in the 00 intensity, associated with the emergence of the 1̄1̄ beam, may be displayed by defocussing the diffraction pattern. The display consists of a dark line that crosses the 00 spot. In experiments at different angles of incidence, the energy at which the line crosses the spot center differs by a fixed amount from the 1̄1̄ emergence energy. The observation is explained in detail on the basis of the resonance mechanism. The resonance minimum is displayed in another way in multiple exposure photographs of the diffraction pattern of a stress-annealed pyrolytic (rotationally disordered) graphite sample in which successive exposures correspond to small increments in the angle of incidence. The photographs are criss-crossed by dark lines, which is identified with the loci of resonance conditions. The observation of resonance effects is interpreted as evidence for long-range dynamical interactions involving ≳ 10 4 atoms per atom layer in the crystal.