The present research was conducted by the Research Grant of Kwangwoon University in 2019.

CAUTION: All appropriate safety practices must be followed when using lasers12 and chemical products, including the use of personal protective equipment such as safety goggles, glasses, gloves, and lab coats.
1. Content creation
<ol>
	<li>Model the different elements of the scene (character and background) with 3D computer graphics programs such as Blender, a free and open-source 3D software toolset.</li>
	<li>Create a 12-frame cyclic animation with the 3D computer graphics program.</li>
	<li>3D print and paint the different elements.
	<ol>
		<li>Print characters and background at the same scale using a fused deposition modeling (FDM) monochrome 3D printer13, with a white polylactic acid (PLA) filament.</li>
		<li>Use sandpaper to eliminate printing defects.</li>
		<li>Hand-paint the different elements with acrylic paint. 
		CAUTION: To avoid unpleasant odors, paint outdoors or use ventilation.</li>
	</ol>
	</li>
	<li>Set up the recording box. Fix the background in a rigid wooden box to avoid movement and place the different 3D printed characters inside one after another to allow the recording of the different 4 inch x 5 inch holograms. 
	NOTE: To avoid movement during hologram recording, firmly attach the individual elements using glue or plasticine, without applying stress.</li>
</ol>
2. Hologram recording
<ol>
	<li>On an optical table, assemble a Denisyuk single-beam full-color optical setup9,10 to record the holograms. 
	NOTE: To record the different holograms, the three RGB lasers used are a red HeNe, 633 nm, 20 mW; a green diode-pumped solid-state (DPSS), 532 nm, 100 mW adjusted to 20 mW; and a blue DPSS 473 nm 50 mW adjusted to 20 mW. The spatial filter is equipped with a 40x, 0.65 NA achromatic microscope objective and a 10 &#956;m pinhole.
	<ol>
		<li>Combine the 3 laser beams (red, green, and blue) with an X-cube prism to get a white laser beam that passes through the same spatial filter. 
		NOTE: Use two mirrors for the red and blue lasers to get four degrees of freedom and perfectly align the three beams.</li>
		<li>From a distance of 1 m and an angle of 45&#176;, illuminate the recording box with the divergent beam.</li>
		<li>Adjust the distance of the three lasers from the cube to get similar beam diameters projected on the object plane. 
		NOTE: The recording box has to be illuminated with a wide, clean and homogeneous divergent white beam.</li>
	</ol>
	</li>
	<li>Use a power meter to adjust the color balance and determine the exposure time.
	<ol>
		<li>Measure the intensity of each laser horizontally, at the position of the holographic plate (see Table of Materials). Since the plate material is isopanchromatic, adjust the color balance equally for the 3 lasers. 
		NOTE: The power-meter used allows direct reading of the power of the 633 nm red laser. For the 473 nm blue and 532 nm green lasers, it is necessary to apply a correction coefficient (x0.4 for blue and x0.6 for green).</li>
		<li>Determine the exposure time before recording the hologram, according to the following formula: 
		<img alt="Equation 1" src="/files/ftp_upload/60459/60459eq1.jpg" /> (1)</li>
		<li>where t is the exposure time (s), H the sensitivity of the material (J/cm2) and E the intensity of the laser (W/cm2). E is measured at the position of the holographic plate with a power meter. 
		NOTE: The sensitivity of the materials used here is 200 &#956;J/cm2 per laser for a full-color (RGB) hologram. The intensity of each laser at the position of the holographic plate, measured with the power-meter is 17 &#956;W/cm&#178; per laser, and the exposure time is 12 s according formula (1).</li>
	</ol>
	</li>
	<li>Close the laser beam with a shutter. 
	NOTE: Use an electronic shutter with a timer to control the exposure time precisely.</li>
	<li>Prepare plates. 
	CAUTION: Handle the plate edges using gloves, and do not allow skin contact with the emulsion at any time.
	<ol>
		<li>Remove holographic plates them from the refrigerator to avoid a shift and store them at room temperature (20&#8211;25 &#176;C) for 1 h before recording. 
		NOTE: The plates used here have to be refrigerated at 4 &#176;C.</li>
		<li>Darken the upper edge of the plate with a black marker to avoid internal reflection.</li>
	</ol>
	</li>
	<li>Set up the recording plate under a green safelight.
	<ol>
		<li>Blow onto the plate to determine the emulsion side. Steam appears only on the glass side.</li>
		<li>Place the holographic plate emulsion-side down on the recording box. Allow it to stabilize for 5 min before recording.</li>
	</ol>
	</li>
	<li>Open the shutter to expose the recording plate, during the time previously calculated with the formula (1).</li>
	<li>Keep the recorded plate in a closed box away from light.</li>
</ol>
3. Hologram development
NOTE: Holograms are developed with a safe and non-staining chemical process developed for the ultimate emulsions.
<ol>
	<li>Once the plate has been exposed, prepare 100 mL of developer for a 4 inch x 5 inch plate. Mix the developer at a ratio of 1 part developer to 10 parts distilled or demineralized water (1:10). 
	NOTE: The developer is stocked in a concentrated solution in a closed bottle to prevent oxidation and needs to be diluted with distilled or demineralized water just before processing.</li>
	<li>Heat the developer to 22 &#176;C precisely. 
	NOTE: The water temperature must be equal to or greater than 20 &#176;C for the developer to function properly. For repetitions, control the temperature before development with a thermometer.</li>
	<li>Under a green safelight, place the exposed plate in the tray and submerge it quickly, emulsion-side up, into the developer and agitate slowly for 4 min precisely. At the end of the development, the plate attains a pale yellow/orange color. 
	NOTE: The development process becomes visible a few seconds after the plate is fully covered with the developer. Use an insulated tray with a lid to maintain a constant temperature during development. Further development to attempt to get a black density is not required.</li>
	<li>Remove the developer and wash the plate in its tray under running tap water for 30 s, allowing the water to overflow into a sink.</li>
	<li>Under normal light, place the developed plate in the tray and submerge it quickly, emulsion-side up, into the bleach without agitation until the plate becomes fully transparent. The bleaching process becomes visible a few seconds after the plate is fully submerged. 
	NOTE: The typical bleaching time is 3 to 5 min at room temperature (20&#8211;25 &#176;C).</li>
	<li>Remove the bleach and wash the plate in its tray under running tap water for 2 min, allowing the water to overflow into a sink. 
	NOTE: When the plate is still in a wet state after bleaching, a hologram can be observed by transmission with a halogen spot. When the hologram is successful, this image will appear very strong.</li>
	<li>Place the plate in the tray and submerge it, emulsion-side up, into a demineralized or distilled water solution with some drops of wetting agent without agitation for 1 min.</li>
	<li>Remove the plate from the tray and dry it vertically for 15-20 min.</li>
	<li>Repeat these operations for each of the 12 holograms. Before recording, in order to place the different objects in the recording box with great precision, apply a holographic onion-skin method by replacing the previous transparent hologram at its recording position, and observe both images at the same time under laser illumination to check that the new character is well-positioned. 
	NOTE: Onion skinning is a procedure usually used in stop-motion animation to see two different frames at the same time.</li>
</ol>
4. Hologram sealing
NOTE: Holograms are protected by a second clean glass plate sealed to the hologram using optical ultraviolet (UV) glue.
<ol>
	<li>Use a scalpel to scrape off 5 mm of the emulsion around the edges. 
	NOTE: This operation is easier when the plate is still wet.</li>
	<li>Laminate the hologram to a clean glass plate of equal size (4 inch x 5 inch), with 1 mL of UV glue. 
	NOTE: To facilitate lamination, pre-heat the glue, the hologram and the clean glass plate in an oven at 30 &#176;C for 10 min.</li>
	<li>Expose the clean glass side of the hologram to sunlight; the UV glue will harden within 5 min. 
	NOTE: It is also possible to use a UV lamp, but strong UV exposure should be avoided.</li>
	<li>Wash the sealed hologram with water and soap, dry it with tissue paper and blacken the back of it with matte black spray paint.</li>
</ol>
5. Fantatrope assembly and operation
<ol>
	<li>Mount the 12 holograms in chronological order in the regularly placed frames of a Fantatrope. 
	NOTE: Gentet et al. 20197 describe the manufacture and operation of a Fantatrope.</li>
	<li>Rotate the Fantatrope at constant speed. An RGB LED strobe light synchronized with the rotation speed successively illuminates the different frames to create a rapid succession of images and produce the illusion of movement. 
	NOTE: A rotation of one turn per second is enough to get the sense of a fluid motion.</li>
</ol>

<ol>
	<li>Geng, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+display+technologies.">Three-dimensional display technologies.</a> Advances in Optics and Photonics. 5 (4), 456-535 (2013).</li><li>Lim, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=360-degree+tabletop+electronic+holographic+display.">360-degree tabletop electronic holographic display.</a> Optics Express. 24 (22), 2499 (2016).</li><li>Sugie, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-performance+parallel+computing+for+next-generation+holographic+imaging.">High-performance parallel computing for next-generation holographic imaging.</a> Nature Electronics. 1 (4), 254 (2018).</li><li>Ogle, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Some+aspects+of+stereoscopic+depth+perception.">Some aspects of stereoscopic depth perception.</a> JOSA. 57, 1073-1081 (1967).</li><li>Read, J. C. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Balance+and+coordination+after+viewing+stereoscopic+3D+television.">Balance and coordination after viewing stereoscopic 3D television.</a> Royal Society Open Science. 2, 140522 (2015).</li><li>Lambooij, M., Ijsselsteijn, W., Fortuin, M., Heynderickx, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visual+discomfort+and+visual+fatigue+of+stereoscopic+displays:+a+review.">Visual discomfort and visual fatigue of stereoscopic displays: a review.</a> Journal of Imaging Science and Technology. 53 (3), 1-14 (2009).</li><li>Gentet, P., Joung, J., Gentet, Y., Hamacher, A., Lee, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fantatrope,+a+moving+hologram+display:+design+and+implementation.">Fantatrope, a moving hologram display: design and implementation.</a> Optics Express. 27 (8), 11571-11584 (2019).</li><li>Denisyuk, Y. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+reproduction+of+the+optical+properties+of+an+object+by+the+wave+field+of+its+scattered+radiation.">On the reproduction of the optical properties of an object by the wave field of its scattered radiation.</a> Optics and Spectroscopy. 14, 279-284 (1963).</li><li>Bjelkhagen, H. I., Brotherton-Ratcliffe, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Ultra-realistic imaging: advanced techniques in analogue and digital colour holography. , (2013).</li><li>Graham, S., Zacharovas, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Practical Holography, Fourth Edition. , (2015).</li><li>Gentet, P., Gentet, Y., Lee, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultimate+04+the+new+reference+for+ultra-realistic+color+holography.">Ultimate 04 the new reference for ultra-realistic color holography.</a> 2017 International Conference on Emerging Trends &amp; Innovation in ICT (ICEI). , 162-166 (2017).</li><li>International Electrotechnical Commission. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=IEC+60825-1:+2014.+Safety+of+laser+products-Part+1:+Equipment+classification+and+requirements.">IEC 60825-1: 2014. Safety of laser products-Part 1: Equipment classification and requirements.</a> IEC Geneva. 3, (2014).</li><li>Kun, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reconstruction+and+development+of+a+3D+printer+using+FDM+technology.">Reconstruction and development of a 3D printer using FDM technology.</a> Procedia Engineering. 149, 203-211 (2016).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Covestro Deutschland AG, Bayfol HX200 Datasheet. , (2018).</li><li>Bjelkhagen, H. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silver+Halide+Recording+Materials+for+Holography+and+Their+Processing.">Silver Halide Recording Materials for Holography and Their Processing.</a> Springer Series in Optical Sciences. 66, (1993).</li></ol>

Philippe Gentet, Lyoung-Hui Kim, Kwang-Jib Kim and Seung-Hyun Lee declare that they have no conflict of interest. Yves Gentet is the manufacturer of the emulsion used here.

Traditionally, stop-motion film uses puppets or clay models. To avoid movement and obtain a bright image at the time of hologram recording, a set of 3D printed characters and backgrounds are chosen. Furthermore, the different elements are attached firmly and without stress in the box. If an element is fixed with constraint or moves during the recording, it will appear black or fringed in the final hologram. 3D printing is a very interesting new tool for creating original models for analog holography.
<p class="jove_c...

Three-dimensional (3D) displays are an important research topic1,2,3 and most of the current approaches use the stereoscopic principle4 that causes visual discomfort and fatigue5,6. The Fantatrope is a convenient new type of dynamic holographic 3D display that can show a short animation in full color without the need for special viewing aids7. A Fantatrope uses a series of twelve full-color holograms corresponding to the different phases of an animation. All holograms used in this device must be ultra-realistic and present the same brightness, transparency, and homogeneous colors. The recording of a single high-quality full-color hologram remains difficult even for experienced practitioners. While the choices of the recording technique and holographic material are important key points, there are several more details that are crucial to successfully record such holograms.
For this protocol, a cyclic sequence of twelve different images is first created with a 3D computer graphics program and all the elements are 3D printed to become hologram models. These holograms are recorded with the single-beam method8 introduced by Yuri Denisyuk in 1963 that allows the recording of ultra-realistic holograms with a 180&#176; full-parallax. A Denisyuk full-color setup uses three different lasers (red, green, and blue) combined to get a white laser beam. Silver-halide emulsions are the best choice of recording material9 and only a few silver-halide full-color emulsions are available9,10. Furthermore to record the blue wavelength without blur, an iso-panchromatic emulsion with a resolution of more than 10,000 lines/mm is required.
In this protocol, the set of holograms are recorded on 4 inch x 5 inch plates, using a material that is specially designed for recording full-color analog holograms without any diffusion and is made isopanchromatic for all the common visible lasers used in color holography (see Table of Materials). The grain is so fine (4 nm) that any visible wavelength can be recorded inside without any diffusion11. Furthermore, each hologram is developed using a safe, non-staining chemical process developed for the ultimate emulsions.
This detailed protocol is intended to help new and experienced practitioners in the field of analog holography to avoid many common pitfalls associated with recording full-color Denisyuk holograms; it can also provide an approach to learn how to use ultimate silver-halide holographic materials and chemicals to obtain reliable and reproducible results.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Black marker</td>
			<td>Monami</td>
			<td>Magic Cap</td>
			<td></td>
		</tr>
		<tr>
			<td>FDM monochrome 3D printer</td>
			<td>Anet</td>
			<td>A8</td>
			<td></td>
		</tr>
		<tr>
			<td>Holographic bleach</td>
			<td>Ultimate Holography</td>
			<td>BLEACH-1L</td>
			<td>Non-toxic</td>
		</tr>
		<tr>
			<td>Holographic developer</td>
			<td>Ultimate Holography</td>
			<td>REV-U08-1.2</td>
			<td>Non-toxic</td>
		</tr>
		<tr>
			<td>Holographic plates</td>
			<td>Ultimate Holography</td>
			<td>U04P-VICOL-4X5</td>
			<td>Light-sensitive</td>
		</tr>
		<tr>
			<td>Laser (DPSS 532 nm 100 mW)</td>
			<td>Cobolt</td>
			<td>Samba</td>
			<td>Follow safety practices</td>
		</tr>
		<tr>
			<td>Laser (DPSS 473 nm 50 mW)</td>
			<td>Cobolt</td>
			<td>Blue</td>
			<td>Follow safety practices</td>
		</tr>
		<tr>
			<td>Laser (HeNe 633 nm 21 mW)</td>
			<td>Thorlabs</td>
			<td>HNL210L</td>
			<td>Follow safety practices</td>
		</tr>
		<tr>
			<td>Laser power meter</td>
			<td>Sanwa</td>
			<td>LP1</td>
			<td></td>
		</tr>
		<tr>
			<td>Matte black spray paint</td>
			<td>Plasti-kote</td>
			<td>3101</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope objective</td>
			<td>Edmund Optics</td>
			<td>40X 0.65 NA</td>
			<td></td>
		</tr>
		<tr>
			<td>Pinhole</td>
			<td>Edmund Optics</td>
			<td>10 &#956;m</td>
			<td></td>
		</tr>
		<tr>
			<td>Spatial Filter Movement</td>
			<td>Edmund Optics</td>
			<td>39-976</td>
			<td></td>
		</tr>
		<tr>
			<td>UV glue</td>
			<td>Vitralit</td>
			<td>6127</td>
			<td>Use gloves</td>
		</tr>
		<tr>
			<td>Wetting agent</td>
			<td>Kodak</td>
			<td>Photo-Flo</td>
			<td></td>
		</tr>
		<tr>
			<td>White PLA filament</td>
			<td>Hatchbox</td>
			<td>PLA-1KG1.75-BLK</td>
			<td></td>
		</tr>
		<tr>
			<td>X-cube</td>
			<td>Edmund Optics</td>
			<td>54-823</td>
			<td></td>
		</tr>
	</tbody>
</table>

recording ultra-realistic full-color analog holograms for use in a moving hologram display

This paper demonstrates a method to record a set of twelve ultra-realistic full-color analog holograms presenting the same brightness, transparency and homogeneous colors for the fabrication of a Fantatrope, a dynamic holographic 3D display, without the need for special viewing aids. The method involves the use of 3D printer technology, a single-beam full-color Denisyuk optical setup with three low-power lasers (red, green, and blue) and an iso-panchromatic high-sensitive silver-halide holographic emulsion specially designed for recording analog holograms without any diffusion. A cyclic animation is created with a 3D computer graphics program and different elements are 3D printed to form models for the holograms. Holograms are recorded with a full-color holographic setup and developed using two simple chemical baths. To prevent any emulsion thickness variations, the holograms are sealed with optical glue. Results confirm that all holograms recorded with this protocol present the same characteristics, which allow them to be used in the Fantatrope.

3D content was created and a cyclic sequence of twelve images was imagined, and the different elements were then 3D printed and painted (Figure 1). A Denisyuk single-beam full-color optical setup was assembled to record holograms (Figure 2). After recording, the holograms were developed and sealed (Figure 3) to obtain a set of twelve ultra-realistic full-color analog holograms with a 180&#176; full-parallax, showing the same brightness, transparency and homogeneous color...

Watch this Scientific Journal Video about Recording Ultra-Realistic Full-Color Analog Holograms for Use in a Moving Hologram Display at JoVE.com

Recording Ultra-Realistic Full-Color Analog Holograms for Use in a Moving Hologram Display

We present a protocol to record a set of ultra-realistic full-color analog holograms, showing the same brightness, transparency, and homogeneous colors, on ultra-fine-grain silver-halide holographic emulsions for the fabrication of a dynamic holographic 3D display.

This paper demonstrates a method to record a set of twelve ultra-realistic full-color analog holograms presenting the same brightness, transparency and ...

recording-ultra-realistic-full-color-analog-holograms-for-use-moving

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

9.5K Views.  Kwangwoon University. We present a protocol to record a set of ultra-realistic full-color analog holograms, showing the same brightness, transparency, and homogeneous colors, on ultra-fine-grain silver-halide holographic emulsions for the fabrication of a dynamic holographic 3D display.

Video: Recording Ultra-Realistic Full-Color Analog Holograms for Use in a Moving Hologram Display

Time Multiplexing Super Resolving Technique for Imaging from a Moving Platform

We propose a method for increasing the resolution of an object and overcoming the diffraction limit of an optical system installed on top of a moving imaging system, such as an airborne platform or satellite. The resolution improvement is obtained in a two-step process. First, three low resolution differently defocused images are being captured and the optical phase is retrieved using an improved iterative Gerchberg-Saxton based algorithm. The phase retrieval allows to numerically back propagate the field to the aperture plane. Second, the imaging system is shifted and the first step is repeated. The obtained optical fields at the aperture plane are combined and a synthetically increased lens aperture is generated along the direction of movement, yielding higher imaging resolution. The method resembles a well-known approach from the microwave regime called the Synthetic Aperture Radar (SAR) in which the antenna size is synthetically increased along the platform propagation direction. The proposed method is demonstrated through laboratory experiment.

A method for overcoming the optical diffraction limit is presented. The method includes a two-step process: optical phase retrieval using iterative Gerchberg-Saxton algorithm, and imaging system shifting followed by repetition of the first step. A synthetically increased lens aperture is generated along the direction of movement, yielding higher imaging resolution.

We propose a method for increasing the resolution of an object and overcoming the diffraction limit of an optical system installed on top of a moving ...

Preparation and Use of Photocatalytically Active Segmented Ag|ZnO and Coaxial TiO2-Ag Nanowires Made by Templated Electrodeposition

Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and reduction half reactions, and fast electron (hole) diffusion and charge separation. Nanowires present suitable architectures to meet these requirements. Axially segmented Ag|ZnO and radially segmented (coaxial) TiO2-Ag nanowires with a diameter of 200 nm and a length of 6-20 &#181;m were made by templated electrodeposition within the pores of polycarbonate track-etched (PCTE) or anodized aluminum oxide (AAO) membranes, respectively. In the photocatalytic experiments, the ZnO and TiO2 phases acted as photoanodes, and Ag as cathode. No external circuit is needed to connect both electrodes, which is a key advantage over conventional photo-electrochemical cells. For making segmented Ag|ZnO nanowires, the Ag salt electrolyte was replaced after formation of the Ag segment to form a ZnO segment attached to the Ag segment. For making coaxial TiO2-Ag nanowires, a TiO2 gel was first formed by the electrochemically induced sol-gel method. Drying and thermal annealing of the as-formed TiO2 gel resulted in the formation of crystalline TiO2 nanotubes. A subsequent Ag electrodeposition step inside the TiO2 nanotubes resulted in formation of coaxial TiO2-Ag nanowires. Due to the combination of an n-type semiconductor (ZnO or TiO2) and a metal (Ag) within the same nanowire, a Schottky barrier was created at the interface between the phases. To demonstrate the photocatalytic activity of these nanowires, the Ag|ZnO nanowires were used in a photocatalytic experiment in which H2 gas was detected upon UV illumination of the nanowires dispersed in a methanol/water mixture. After 17 min&#160;of illumination, approximately 0.2 vol% H2 gas was detected from a suspension of ~0.1 g of Ag|ZnO nanowires in a 50 ml 80 vol% aqueous methanol solution.

Preparation and Use of Photocatalytically Active Segmented Ag|ZnO and Coaxial TiO2-Ag Nanowires Made by Templated Electrodeposition

Procedures are outlined to prepare segmented and coaxial nanowires via templated electrodeposition in nanopores. As examples, segmented nanowires consisting of Ag and ZnO segments, and coaxial nanowires consisting of a TiO2 shell and a Ag core were made. The nanowires were used in photocatalytic hydrogen formation experiments.

Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and ...

Visualization of High Speed Liquid Jet Impaction on a Moving Surface

Two apparatuses for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device (for examining surface speeds between 0 and 25 m/sec) and a spinning disk device (for examining surface speeds between 15 and 100 m/sec). The air cannon linear traverse is a pneumatic energy-powered system that is designed to accelerate a metal rail surface mounted on top of a wooden projectile. A pressurized cylinder fitted with a solenoid valve rapidly releases pressurized air into the barrel, forcing the projectile down the cannon barrel. The projectile travels beneath a spray nozzle, which impinges a liquid jet onto its metal upper surface, and the projectile then hits a stopping mechanism. A camera records the jet impingement, and a pressure transducer records the spray nozzle backpressure. The spinning disk set-up consists of a steel disk that reaches speeds of 500 to 3,000 rpm via a variable frequency drive (VFD) motor. A spray system similar to that of the air cannon generates a liquid jet that impinges onto the spinning disc, and cameras placed at several optical access points record the jet impingement. Video recordings of jet impingement processes are recorded and examined to determine whether the outcome of impingement is splash, splatter, or deposition. The apparatuses are the first that involve the high speed impingement of low-Reynolds-number liquid jets on high speed moving surfaces. In addition to its rail industry applications, the described technique may be used for technical and industrial purposes such as steelmaking and may be relevant to high-speed 3D printing.

Two experimental devices for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device and a spinning disk device. The apparatuses are used to determine optimal approaches to the application of liquid friction modifier (LFM) onto rail tracks for top-of-rail friction control.

Two apparatuses for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device (for examining surface speeds ...

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

A Cost-effective and Reliable Method to Predict Mechanical Stress in Single-use and Standard Pumps

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping process shear forces occur which can lead to qualitative and/or quantitative product loss. To calculate the mechanical stress with limited experimental expense, an oil-water emulsion system was used, whose suitability was demonstrated for drop size detections in bioreactors1. As drop breakup of the oil-water emulsion system is a function of mechanical stress, drop sizes need to be counted over the experimental time of shear stress investigations. In previous studies, the inline endoscopy has been shown to be an accurate and reliable measurement technique for drop size detections in liquid/liquid dispersions. The aim of this protocol is to show the suitability of the inline endoscopy technique for drop size measurements in pumping processes. In order to express the drop size, the Sauter mean diameter d32 was used as the representative diameter of drops in the oil-water emulsion. The results showed low variation in the Sauter mean diameters, which were quantified by standard deviations of below 15%, indicating the reliability of the measurement technique.

Shear stress investigations on an oil-water emulsion system result in drop breakup over the experimental time. To count drop sizes in pumping processes, the suitability of inline endoscopy was successfully demonstrated in this protocol.

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping ...

Use of a Multi-compartment Dynamic Single Enzyme Phantom for Studies of Hyperpolarized Magnetic Resonance Agents

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due to fundamental constraints imposed by the hyperpolarized state, exotic imaging and reconstruction techniques are commonly used. A practical system for characterization of dynamic, multi-spectral imaging methods is critically needed. Such a system must reproducibly recapitulate the relevant chemical dynamics of normal and pathological tissues. The most widely utilized substrate to date is hyperpolarized [1-13C]-pyruvate for assessment of cancer metabolism. We describe an enzyme-based phantom system that mediates the conversion of pyruvate to lactate. The reaction is initiated by injection of the hyperpolarized agent into multiple chambers within the phantom, each of which contains varying concentrations of reagents that control the reaction rate. Multiple compartments are necessary to ensure that imaging sequences faithfully capture the spatial and metabolic heterogeneity of tissue. This system will aid the development and validation of advanced imaging strategies by providing chemical dynamics that are not available from conventional phantoms, as well as control and reproducibility that is not possible in vivo.

A multi-compartment dynamic phantom is used to simulate some biology of interest for metabolic studies using hyperpolarized magnet resonance agents.

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due ...

Design and Use of a Full Flow Sampling System (FFS) for the Quantification of Methane Emissions

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas industry faces continued scrutiny for methane emissions from across the supply chain, due to methane&#39;s relatively high global warming potential (25-84x that of carbon dioxide, according to the Energy Information Administration). Currently, a variety of techniques of varied uncertainties exists to measure or estimate methane emissions from components or facilities. Currently, only one commercial system is available for quantification of component level emissions and recent reports have highlighted its weaknesses.
In order to improve accuracy and increase measurement flexibility, we have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases based on transportation emissions measurement principles. The FFS is a modular system that consists of an explosive-proof blower(s), mass airflow sensor(s) (MAF), thermocouple, sample probe, constant volume sampling pump, laser based greenhouse gas sensor, data acquisition device, and analysis software. Dependent upon the blower and hose configuration employed, the current FFS is able to achieve a flow rate ranging from 40 to 1,500 standard cubic feet per minute (SCFM). Utilization of laser-based sensors mitigates interference from higher hydrocarbons (C2+). Co-measurement of water vapor allows for humidity correction. The system is portable, with multiple configurations for a variety of applications ranging from being carried by a person to being mounted in a hand drawn cart, on-road vehicle bed, or from the bed of utility terrain vehicles (UTVs). The FFS is able to quantify methane emission rates with a relative uncertainty of &#177; 4.4%. The FFS has proven, real world operation for the quantification of methane emissions occurring in conventional and remote facilities.

Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions

We have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases from across the natural gas supply chain.

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas ...

Applying X-ray Imaging Crystal Spectroscopy for Use as a High Temperature Plasma Diagnostic

X-ray spectra provide a wealth of information on high temperature plasmas; for example electron temperature and density can be inferred from line intensity ratios. By using a Johann spectrometer viewing the plasma, it is possible to construct profiles of plasma parameters such as density, temperature, and velocity with good spatial and time resolution. However, benchmarking atomic code modeling of X-ray spectra obtained from well-diagnosed laboratory plasmas is important to justify use of such spectra to determine plasma parameters when other independent diagnostics are not available. This manuscript presents the operation of the High Resolution X-ray Crystal Imaging Spectrometer with Spatial Resolution (HIREXSR), a high wavelength resolution spatially imaging X-ray spectrometer used to view hydrogen- and helium-like ions of medium atomic number elements in a tokamak plasma. In addition, this manuscript covers a laser blow-off system that can introduce such ions to the plasma with precise timing to allow for perturbative studies of transport in the plasma.

X-ray spectra provide a wealth of information on high temperature plasmas. This manuscript presents the operation of a high wavelength resolution spatially imaging X-ray spectrometer used to view hydrogen- and helium-like ions of medium atomic number elements in a tokamak plasma.

X-ray spectra provide a wealth of information on high temperature plasmas; for example electron temperature and density can be inferred from line ...

Method for Recording Broadband High Resolution Emission Spectra of Laboratory Lightning Arcs

Lightning is one of the most common and destructive forces in nature and has long been studied using spectroscopic techniques, first with traditional camera film methods and then digital camera technology, from which several important characteristics have been derived. However, such work has always been limited due to the inherently random and non-repeatable nature of natural lightning events in the field. Recent developments in lightning test facilities now allow the reproducible generation of lightning arcs within controlled laboratory environments, providing a test bed for the development of new sensors and diagnostic techniques to understand lightning mechanisms better. One such technique is a spectroscopic system using digital camera technology capable of identifying the chemical elements with which the lightning arc interacts, with these data then being used to derive further characteristics. In this paper, the spectroscopic system is used to obtain the emission spectrum from a 100 kA peak, 100 &#181;s duration lightning arc generated across a pair of hemispherical tungsten electrodes separated by a small air gap. To maintain a spectral resolution of less than 1 nm, several individual spectra were recorded across discrete wavelength ranges, averaged, stitched, and corrected to produce a final composite spectrum in the 450 nm (blue light) to 890 nm (near infrared light) range. Characteristic peaks within the data were then compared to an established publicly available database to identify the chemical element interactions. This method is readily applicable to a variety of other light emitting events, such as fast electrical discharges, partial discharges, and sparking in electrical equipment, apparatus, and systems.

Emission spectroscopy techniques have traditionally been used to analyze inherently random lightning arcs occurring in nature. In this paper, a method developed to obtain the emission spectroscopy from reproducible lightning arcs generated within a laboratory environment is described.

Lightning is one of the most common and destructive forces in nature and has long been studied using spectroscopic techniques, first with traditional ...

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

An analog, macroscopic method for studying molecular-scale hydrodynamic processes in dense gases and liquids is described. The technique applies a standard fluid dynamic diagnostic, particle image velocimetry (PIV), to measure: i) velocities of individual particles (grains), extant on short, grain-collision time-scales, ii) velocities of systems of particles, on both short collision-time- and long, continuum-flow-time-scales, iii) collective hydrodynamic modes known to exist in dense molecular fluids, and iv) short- and long-time-scale velocity autocorrelation functions, central to understanding particle-scale dynamics in strongly interacting, dense fluid systems. The basic system is composed of an imaging system, light source, vibrational sensors, vibrational system with a known media, and PIV and analysis software. Required experimental measurements and an outline of the theoretical tools needed when using the analog technique to study molecular-scale hydrodynamic processes are highlighted. The proposed technique provides a relatively straightforward alternative to photonic and neutron beam scattering methods traditionally used in molecular hydrodynamic studies.

An experimentally accessible analog method for studying molecular hydrodynamic processes in dense fluids is presented. The technique uses particle image velocimetry of vibrated, high-restitution grain piles and allows direct, macroscopic observation of dynamical processes known and predicted to exist in strongly interacting, high density gases and liquids.