The authors would like to thank the Danish Council for Independent research for funding the project (Grant DDF - 1335-00282). COWIfonden funded the construction of the Crude Oil Flammability Apparatus and the gas analyzer, including the duct insert. Maersk Oil and Statoil provided the crude oils that were used for the representative results. None of the sponsors have been involved in the protocol or the results of this paper. The authors would also like to thank Ulises Rojas Alva for assistance with constructing the modified cone sample holder.

<ol>
	<li>Allen, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contained+Controlled+Burning+of+Spilled+Oil+During+the+Exxon+Valdez+Oil+Spill.">Contained Controlled Burning of Spilled Oil During the Exxon Valdez Oil Spill.</a> , 305-313 (1990).</li><li>Allen, A. A., Jaeger, D., Mabile, N. 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J., Fritt-Rasmussen, J., Daniloff, R., Leirvik, F., Resby, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Establishing, testing and verification of a laboratory burning cell to measure ignitability for in situ burning of oil spills. Report No. 20, 26. 20, (2010).</li><li>Van Gelderen, L., Malmquist, L. M. V., Jomaas, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vaporization+order+and+burning+efficiency+of+crude+oils+during+in+situ+burning+on+water.">Vaporization order and burning efficiency of crude oils during in situ burning on water.</a> Fuel. 191, 528-537 (2017).</li><li>Farmahini Farahani, H., Shi, X., Simeoni, A., Rangwala, A. 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The authors have nothing to disclose.

The two weathering methods discussed in this paper are a relatively simple approximation of the weathering processes that a spilled oil on water is subjected to17. Other, more sophisticated weathering methods can also be used to provide weathered crude oil samples, such as the circulating flume described by Brandvik and Faksness35. The advantage of the presented methods is that they require simple equipment and can be easily conducted in a laboratory environment. The result...

In situ burning of spilled crude oil on water is a marine oil spill response method that removes the spilled oil from the water surface by burning it and converting it to soot and gaseous combustion products. This response method was successfully applied during the Exxon Valdez1 and Deepwater Horizon2 oil spills and is regularly mentioned as a potential oil spill response method for the Arctic3,4,5,6. Two of the key parameters that determine whether in situ burning of oil will be successful as a spill response method are the flammability and the burning efficiency of the oil. The first parameter, flammability, describes how easily a fuel can be ignited and can lead to flame spreading over the fuel surface to result in a fully developed fire. The second parameter, burning efficiency, expresses the amount of the oil (in wt%) that is effectively removed from the water surface by the fire. It is thus relevant to understand the flammability and the expected burning efficiency of different crude oils under in situ burning conditions.
The ignition of oil slicks on water for in situ burning purposes is commonly addressed as a practical problem, with qualitative discussions on ignition systems5,7,8,9. The practical approach to the ignition of spilled oil as a binary problem, and labelling oils either &#34;ignitable&#34; or &#34;not ignitable&#34; (e.g. Brandvik, Fritt-Rasmussen, et al.10) is, however, incorrect from a fundamental point of view. In theory, any fuel can be ignited given an appropriate ignition source. It is therefore relevant to quantify the ignition requirements for a wide range of different crude oil types to better understand the properties of a crude oil that would label it as &#34;not ignitable&#34;. For this purpose, the developed method can be used to study the ignition delay time of an oil as a function of the incident heat flux, the critical heat flux of the oil and its thermal inertia, i.e. how difficult it is to heat up the oil.
In a previous study, we postulated that the main parameter that governs the burning efficiency is the heat feedback to the fuel surface11, which is a function of the pool diameter. The theory explains the apparent pool size dependency of the burning efficiency based on laboratory studies reporting low burning efficiencies (32-80%)8,12,13 and large scale studies (pool diameter &#8805;2 m) reporting high burning efficiencies (90-99%)14,15,16. The method discussed herein was designed to test the proposed theory. By subjecting small scale laboratory experiments to a constant external heat flux, the higher heat feedback for large scale pool fires can be simulated under controlled laboratory conditions. As such, the developed method allows studying the burning efficiency effectively as a function of the diameter by varying the external heat flux.
In addition to an external heat flux to simulate the larger scale of in situ burning operations, the experimental setups feature cooling of the oil slick by a cold-water flow, simulating the cooling effect of the sea current. The discussed method is furthermore compatible with both fresh and weathered crude oils. The weathering of crude oil describes the physical and chemical process that affect a crude oil once it is spilled on water, such as losses of its volatile components and mixing with water to form water-in-oil emulsions (e.g., AMAP17). Evaporation and emulsification are two of the main weathering processes that affect the flammability of crude oils18 and protocols for simulating these weathering processes are therefore included in the discussed method.
Herein, we present a novel laboratory method that determines the flammability and burning efficiency of crude oil under conditions that simulate in situ burning operations on sea. Previous studies on the flammability and burning efficiency of crude oils featured both comparable and different methods. The flammability of fresh and weathered crude oils as a function of an external heat flux was studied on water19 and under Arctic temperatures20. Burning efficiency studies typically focus on different types of fresh and weathered crude oils and environmental conditions at a fixed scale (e.g., Fritt-Rasmussen, et al.8 Bech, Sveum, et al.21). A recent study on the burning of crude oils contained by chemical herders is, to the knowledge of the authors, the first to study the burning efficiency for small, intermediate, and large scale experiments under similar conditions13. Large scale experiments are, however, not readily available for parametric studies due to the extensive amount of time and resources required for conducting such experiments. The main advantage of the presented method over the previously mentioned studies is that it allows for simultaneously studying both the flammability and burning efficiency of crude oil under semi-realistic conditions. The combination of studying these two parameters for crude oils as a function of both different oil types and the (simulated) pool diameter through easily repeatable experiments was previously unfeasible in practice.

<table border="0" cellpadding="0" cellspacing="0" width="943">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">DUC Crude Oil</td>
			<td style="width:139px;">Maersk</td>
			<td style="width:132px;">N/A</td>
			<td style="width:464px;">Light crude oil with r = 0.853 g/ml and h = 6.750 mPa*s.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">Grane Crude Oil</td>
			<td style="width:139px;">Statoil</td>
			<td style="width:132px;">N/A</td>
			<td style="width:464px;">Heavy crude oil with r = 0.925 g/ml and h = 133.6 mPa*s.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:208px;">SVM 3000 Stabinger Viscometer</td>
			<td style="width:139px;">Anton Paar</td>
			<td style="width:132px;">C18IP007EN-P</td>
			<td style="width:464px;">Viscosity and density meter for the fresh and weathered crude oils.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">Laboshake RO500</td>
			<td style="width:139px;">Gerhardt</td>
			<td style="width:132px;">11-0002</td>
			<td style="width:464px;">Rotary shaking table for emulsifying water and oil mixtures.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:208px;">Jebao Wave Maker RW-4</td>
			<td style="width:139px;">Jebao</td>
			<td style="width:132px;">N/A</td>
			<td style="width:464px;">Propeller (flow of 500-4000 L/h) used in the COFA setup to generate a current.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">Aquabee UP 3000</td>
			<td style="width:139px;">Aquabee</td>
			<td style="width:132px;">UP 3000</td>
			<td style="width:464px;">Aquarium pump for cooling of heat flux gauge.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:208px;">Adventurer Precision Electronic Balance</td>
			<td style="width:139px;">OHAUS</td>
			<td style="width:132px;">AX5205</td>
			<td style="width:464px;">Load scale used to weigh the oil for the COFA experiments and in the custom-made cone sample holder for the cone setup.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:208px;">3M Oil Sorbent Pads</td>
			<td style="width:139px;">VWR</td>
			<td>MMMAHP156</td>
			<td style="width:464px;">Hydrophobic absorption pads used to collect oil residues to determine the burning efficiency of the fire.</td>
		</tr>
		<tr height="66">
			<td height="66" style="height:66px;width:208px;">Mass Loss Calorimeter</td>
			<td style="width:139px;">Fire Testing Technology (FTT)</td>
			<td style="width:132px;">B11325-650-1-1608</td>
			<td style="width:464px;">A custom-made, circular holder was used for the testing of crude oil rather than the standard square sample holder. Includes a heat flux gauge with a range up to 100 kW/m2.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:208px;">34972A Data Acquisition / Data Logger Switch Unit</td>
			<td>RS Components Ltd.</td>
			<td style="width:132px;">702-7958</td>
			<td style="width:464px;">Produced by Keysight Technologies. Operated by Keysight benchLink data logger 3 software and equipped with a 20-channel multiplexer.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:208px;">Keysight Technologies 34901A 20-channel multiplexer</td>
			<td>RS Components Ltd.</td>
			<td style="width:132px;">702-7939</td>
			<td style="width:464px;">Produced by Keysight Technologies.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Bellows-Sealed Valve</td>
			<td style="width:139px;">Swagelok</td>
			<td style="width:132px;">SS-1GS6MM</td>
			<td style="width:464px;">Toggle valve to open/close the water in- and outlet of the custom-made cone sample holder for the cone setup.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:208px;">Kronos 50 Peristaltic Pump</td>
			<td style="width:139px;">SEKO</td>
			<td style="width:132px;">KRFM0210M6000</td>
			<td style="width:464px;">Peristaltic pump used to cool the custom-made cone sample holder for the cone setup.</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:208px;">ARCTIC A28 Refrigerated Circulater</td>
			<td style="width:139px;">ThermoFisher Scientific</td>
			<td>152-5281</td>
			<td style="width:464px;">Water cooling reservoir used to cool the cooling water that flows through the custom-made cone sample holder for the cone setup. Includes a SC 100 Immersion Circulator controller.</td>
		</tr>
		<tr height="46">
			<td height="46" style="height:46px;width:208px;">Gas Analysis Instrumentation Console with Duct Insert</td>
			<td style="width:139px;">Fire Testing Technology (FTT)</td>
			<td style="width:132px;">B11328-650-1-1609</td>
			<td style="width:464px;">Gas analyzer for O2, CO2 and CO. Uses a 34972A Data Acquisition / Data Logger Switch Unit.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:208px;">Ceramic &#38; Stainless Steel 2.5mm Electrode</td>
			<td style="width:139px;">Fire Testing Technology (FTT)</td>
			<td style="width:132px;">M015-4</td>
			<td style="width:464px;">Spark igniter from the Mass Loss Calorimeter. Used in the COFA setup to measure the surface temperature upon ignition.</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:208px;">Infrared Emitter-Module M110/348</td>
			<td style="width:139px;">Heraeus</td>
			<td style="width:132px;">80046199</td>
			<td style="width:464px;">Original Infrared heaters on which the new design with a water-cooled holder for the heating elements was based. Includes two short wave twin tube emitters (09751751). Operated by a type CB1x25 P power controller.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:208px;">Power Controller Heratron&#160;</td>
			<td style="width:139px;">Heraeus</td>
			<td style="width:132px;">80055836</td>
			<td style="width:464px;">Type CB1x25 P power controller for the infrared heaters.</td>
		</tr>
	</tbody>
</table>

experimental procedure for laboratory studies of in situ burning : flammability and burning efficiency of crude oil

A new method for the simultaneous study of the flammability and burning efficiency of fresh and weathered crude oil through two experimental laboratory setups is presented. The experiments are easily repeatable compared to operational scale experiments (pool diameter &#8805;2 m), while still featuring quite realistic in situ burning conditions of crude oil on water. Experimental conditions include a flowing water sub-layer that cools the oil slick and an external heat flux (up to 50 kW/m2) that simulates the higher heat feedback to the fuel surface in operational scale crude oil pool fires. These conditions enable a controlled laboratory study of the burning efficiency of crude oil pool fires that are equivalent to operational scale experiments. The method also provides quantitative data on the requirements for igniting crude oils in terms of the critical heat flux, ignition delay time as a function of the incident heat flux, the surface temperature upon ignition, and the thermal inertia. This type of data can be used to determine the required strength and duration of an ignition source to ignite a certain type of fresh or weathered crude oil. The main limitation of the method is that the cooling effect of the flowing water sub-layer on the burning crude oil as a function of the external heat flux has not been fully quantified. Experimental results clearly showed that the flowing water sub-layer does improve how representative this setup is of in situ burning conditions, but to what extent this representation is accurate is currently uncertain. The method nevertheless features the most realistic in situ burning laboratory conditions currently available for simultaneously studying the flammability and burning efficiency of crude oil on water.

Figure 5 shows the evaporation curve of a light crude oil that was evaporated over multiple days to a loss of 30 wt% using the method described in step 2. The figure clearly shows that after the first day (19 h) of evaporative weathering, the evaporation rate is reduced significantly, which allows for pauses as mentioned in the protocol.
Figure 6 shows the ignition dela...

Watch this Scientific Journal Video about Experimental Procedure for Laboratory Studies of In Situ Burning : Flammability and Burning Efficiency of Crude Oil at JoVE.com

Experimental Procedure for Laboratory Studies of In Situ Burning : Flammability and Burning Efficiency of Crude Oil

Here, we present a protocol to simultaneously study the flammability and burning efficiency of fresh and weathered crude oil under conditions that simulate in situ burning operations on the sea.

Experimental Procedure for Laboratory Studies of In Situ Burning : Flammability and Burning Efficiency of Crude Oil

A new method for the simultaneous study of the flammability and burning efficiency of fresh and weathered crude oil through two experimental laboratory ...

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12.3K Views.  Technical University of Denmark. Here, we present a protocol to simultaneously study the flammability and burning efficiency of fresh and weathered crude oil under conditions that simulate in situ burning operations on the sea.

Video: Experimental Procedure for Laboratory Studies of In Situ Burning : Flammability and Burning Efficiency of Crude Oil

In-situ Tapering of Chalcogenide Fiber for Mid-infrared Supercontinuum Generation

Supercontinuum generation (SCG) in a tapered chalcogenide fiber is desirable for broadening mid-infrared (or mid-IR, roughly the 2-20 &mu;m wavelength range) frequency combs1, 2 for applications such as molecular fingerprinting, 3 trace gas detection, 4 laser-driven particle acceleration, 5 and x-ray production via high harmonic generation. 6 Achieving efficient SCG in a tapered optical fiber requires precise control of the group velocity dispersion (GVD) and the temporal properties of the optical pulses at the beginning of the fiber, 7 which depend strongly on the geometry of the taper. 8 Due to variations in the tapering setup and procedure for successive SCG experiments-such as fiber length, tapering environment temperature, or power coupled into the fiber, in-situ spectral monitoring of the SCG is necessary to optimize the output spectrum for a single experiment.
	In-situ fiber tapering for SCG consists of coupling the pump source through the fiber to be tapered to a spectral measurement device. The fiber is then tapered while the spectral measurement signal is observed in real-time. When the signal reaches its peak, the tapering is stopped. The in-situ tapering procedure allows for generation of a stable, octave-spanning, mid-IR frequency comb from the sub harmonic of a commercially available near-IR frequency comb. 9 This method lowers cost due to the reduction in time and materials required to fabricate an optimal taper with a waist length of only 2 mm.
	The in-situ tapering technique can be extended to optimizing microstructured optical fiber (MOF) for SCG10 or tuning of the passband of MOFs, 11 optimizing tapered fiber pairs for fused fiber couplers12 and wavelength division multiplexers (WDMs), 13 or modifying dispersion compensation for compression or stretching of optical pulses.14-16

In-situ Tapering of Chalcogenide Fiber for Mid-infrared Supercontinuum Generation

We describe a method for in-situ tapering of As2S3 fibers to achieve efficient mid-infrared supercontinuum generation. By tapering while monitoring the supercontinuum&#x2019;s spectrum, the spectral width can be maximized for a fiber taper. In-situ fiber tapering can be applied to optimize the performance of other fiber-based devices.

Supercontinuum  generation (SCG) in a tapered chalcogenide fiber is desirable for broadening mid-infrared  (or mid-IR, roughly the 2-20 &mu;m wavelength ...

Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System

For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust aggregates with sizes up to ~10 cm and porosities up to 70% can be collided. One of the drop towers is primarily used for very low impact speeds down to below 0.01 m/sec and makes use of a double release mechanism. Collisions are recorded in stereo-view by two high-speed cameras, which fall along the glass vacuum tube in the center-of-mass frame of the two dust aggregates. The other free-fall tower makes use of an electromagnetic accelerator that is capable of gently accelerating dust aggregates to up to 5 m/sec. In combination with the release of another dust aggregate to free fall, collision speeds up to ~10 m/sec can be achieved. Here, two fixed high-speed cameras record the collision events. In both drop towers, the dust aggregates are in free fall during the collision so that they are weightless and match the conditions in the early Solar System.

We present a technique to achieve low-velocity to intermediate-velocity collisions between fragile dust aggregates in the laboratory. For this purpose, two vacuum drop-tower setups have been developed that allow collision velocities between &#60;0.01 and ~10 m/sec. The collision events are recorded by high-speed imaging.

For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust ...

SSVEP-based Experimental Procedure for Brain-Robot Interaction with Humanoid Robots

Brain-Robot Interaction (BRI), which provides an innovative communication pathway between human and a robotic device via brain signals, is prospective in helping the disabled in their daily lives. The overall goal of our method is to establish an SSVEP-based experimental procedure by integrating multiple software programs, such as OpenViBE, Choregraph, and Central software as well as user developed programs written in C++ and MATLAB, to enable the study of brain-robot interaction with humanoid robots.
This is achieved by first placing EEG electrodes on a human subject to measure the brain responses through an EEG data acquisition system. A user interface is used to elicit SSVEP responses and to display video feedback in the closed-loop control experiments. The second step is to record the EEG signals of first-time subjects, to analyze their SSVEP features offline, and to train the classifier for each subject. Next, the Online Signal Processor and the Robot Controller are configured for the online control of a humanoid robot. As the final step, the subject completes three specific closed-loop control experiments within different environments to evaluate the brain-robot interaction performance.
The advantage of this approach is its reliability and flexibility because it is developed by integrating multiple software programs. The results show that using this approach, the subject is capable of interacting with the humanoid robot via brain signals. This allows the mind-controlled humanoid robot to perform typical tasks that are popular in robotic research and are helpful in assisting the disabled.

The overall goal of this method is to establish an SSVEP-based experimental procedure by integrating multiple software programs to enable the study of brain-robot interaction with humanoid robots, which is prospective in assisting the sick and elderly as well as performing unsanitary or dangerous jobs.

Brain-Robot Interaction (BRI), which provides an innovative communication pathway between human and a robotic device via brain signals, is prospective in ...

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices have used devices prepared by spin coating, a process that is not amenable to large-scale fabrication. This mismatch in device fabrication makes it difficult to translate quantitative results obtained in the laboratory to the commercial level, making optimization difficult. Using a mini-slot die coater, this mismatch can be resolved by translating the commercial process to the laboratory and characterizing the structure formation in the active layer of the device in real time and in situ as films are coated onto a substrate. The evolution of the morphology was characterized under different conditions, allowing us to propose a mechanism by which the structures form and grow. This mini-slot die coater offers a simple, convenient, material efficient route by which the morphology in the active layer can be optimized under industrially relevant conditions. The goal of this protocol is to show experimental details of how a solar cell device is fabricated using a mini-slot die coater and technical details of running in situ structure characterization using the mini-slot die coater.

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Here, we present a protocol to fabricate organic thin film solar cells using a mini-slot die coater and related in-line structure characterizations using synchrotron scattering techniques.

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices ...

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames

Modeling the realistic burning behavior of condensed-phase fuels has remained out of reach, in part because of an inability to resolve the complex interactions occurring at the interface between gas-phase flames and condensed-phase fuels. The current research provides a technique to explore the dynamic relationship between a combustible condensed fuel surface and gas-phase flames in laminar boundary layers. Experiments have previously been conducted in both forced and free convective environments over both solid and liquid fuels. A unique methodology, based on the Reynolds Analogy, was used to estimate local mass burning rates and flame heat fluxes for these laminar boundary layer diffusion flames utilizing local temperature gradients at the fuel surface. Local mass burning rates and convective and radiative heat feedback from the flames were measured in both the pyrolysis and plume regions by using temperature gradients mapped near the wall by a two-axis traverse system. These experiments are time-consuming and can be challenging to design as the condensed fuel surface burns steadily for only a limited period of time following ignition. The temperature profiles near the fuel surface need to be mapped during steady burning of a condensed fuel surface at a very high spatial resolution in order to capture reasonable estimates of local temperature gradients. Careful corrections for radiative heat losses from the thermocouples are also essential for accurate measurements. For these reasons, the whole experimental setup needs to be automated with a computer-controlled traverse mechanism, eliminating most errors due to positioning of a micro-thermocouple. An outline of steps to reproducibly capture near-wall temperature gradients and use them to assess local burning rates and heat fluxes is provided.

We describe the use of micro-thermocouples to estimate local temperature gradients in steady laminar boundary layer diffusion flames. By extension of the Reynolds Analogy, local temperature gradients can be further used to estimate the local mass burning rates and heat fluxes in such flames with high accuracy.

Modeling the realistic burning behavior of condensed-phase fuels has remained out of reach, in part because of an inability to resolve the complex ...

Fabrication of White Light-emitting Electrochemical Cells with Stable Emission from Exciplexes

The authors present an approach for fabricating stable white light emission from polymer light-emitting electrochemical cells (PLECs) having an active layer which consists of blue-fluorescent poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD) and &#960;-conjugated triphenylamine molecules. This white light emission originates from exciplexes formed between PFD and amines in electronically excited states. A device containing PFD, 4,4&#39;,4&#39;&#39;-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA), Poly(ethylene oxide) and K2CF3SO3 showed white light emission with Commission internationale de l&#39;&#233;clairage (CIE) coordinates of (0.33, 0.43) and a Color Rendering Index (CRI) of Ra = 73 at an applied voltage of 3.5 V. Constant voltage measurements showed that the CIE coordinates of (0.27, 0.37), Ra of 67, and the emission color observed immediately after application of a voltage of 5 V were nearly unchanged and stable after 300 sec.

The authors present a method for fabricating stable white-light-emitting electrochemical cells utilizing emission from exciplexes formed between a blue-emitting fluorene polymer and aromatic amines.

The authors present an approach for fabricating stable white light emission from polymer light-emitting electrochemical cells (PLECs) having an active ...

Experimental Procedure for Warm Spinning of Cast Aluminum Components

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to improve material properties. With a wide array of processing parameters which can affect both the shape attained and resulting material properties, this type of processing is notoriously difficult to commission. A simplified, light-duty version of the process has been designed and implemented for full-size automotive wheels. The apparatus is intended to assist in understanding the deformation mechanisms and the material response to this type of processing. An experimental protocol has been developed to prepare for, and subsequently perform forming trials and is described for as-cast A356 wheel blanks. The thermal profile attained, along with instrumentation details are provided. Similitude with full-scale forming operations which impart significantly more deformation at faster rates is discussed.

An experimental protocol for instrumented warm rotary forming of cast aluminum alloys employing a bespoke industrially scaled apparatus is presented. Experimental considerations including thermal and mechanical effects are discussed, as well as similitude with full-scale processing of automotive wheels.

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to ...

In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions

To help address production issues in refineries caused by the fouling of process units and lines, we have developed a setup as well as a method to visualize the behavior of petroleum samples under process conditions. The experimental setup relies on a custom-built micro-reactor fitted with a sapphire window at the bottom, which is placed over the objective of an inverted microscope equipped with a cross-polarizer module. Using reflection microscopy enables the visualization of opaque samples, such as petroleum vacuum residues, or asphaltenes. The combination of the sapphire window from the micro-reactor with the cross-polarizer module of the microscope on the light path allows high-contrast imaging of isotropic and anisotropic media. While observations are carried out, the micro-reactor can be heated to the temperature range of cracking reactions (up to 450 &#176;C), can be subjected to H2 pressure relevant to hydroconversion reactions (up to 16 MPa), and can stir the sample by magnetic coupling. 
Observations are typically carried out by taking snapshots of the sample under cross-polarized light at regular time intervals. Image analyses may not only provide information on the temperature, pressure, and reactive conditions yielding phase separation, but may also give an estimate of the evolution of the chemical (absorption/reflection spectra) and physical (refractive index) properties of the sample before the onset of phase separation.

In Situ Visualization of the Phase Behavior of Oil Samples Under Refinery Process Conditions

This article describes a setup and method for the in situ visualization of oil samples under a variety of temperature and pressure conditions that aim to emulate refining and upgrading processes. It is primarily used for studying isotropic and anisotropic media involved in the fouling behavior of petroleum feeds.

To help address production issues in refineries caused by the fouling of process units and lines, we have developed a setup as well as a method to ...

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and forging. Adoption of this technique is proceeding despite disagreement concerning the underlying mechanism responsible for EAD. The experimental procedure described herein enables a more explicit study compared to previous EAD research by removing thermal effects, which are responsible for disagreement in interpreting previous EAD results. Furthermore, as the procedure described here enables EAD observation in situ and in real time in a transmission electron microscope (TEM), it is superior to existing post-mortem methods that observe EAD effects post-test. Test samples consist of a single crystal copper (SCC) foil having a free-standing tensile test section of nanoscale thickness, fabricated using a combination of laser and ion beam milling. The SCC is mounted to an etched silicon base that provides mechanical support and electrical isolation while serving as a heat sink. Using this geometry, even at high current density (~3,500 A/mm2), the test section experiences a negligible temperature increase (&#60;0.02 &#176;C), thus eliminating Joule heating effects. Monitoring material deformation and identifying the corresponding changes to microstructures, e.g. dislocations, are accomplished by acquiring and analyzing a series of TEM images. Our sample preparation and in situ experiment procedures are robust and versatile as they can be readily utilized to test materials with different microstructures, e.g., single and polycrystalline copper.

A Novel Method for In Situ Electromechanical Characterization of Nanoscale Specimens

Isolating electrical and thermal effects on electrically assisted deformation (EAD) is very difficult using macroscopic samples. Metallic sample micro- and nanostructures together with a custom test procedure have been developed to evaluate the impact of applied current on the formation without joule heating and evolution of dislocations on these samples.

Electrically assisted deformation (EAD) is increasingly being used to improve the formability of metals during processes such as sheet metal rolling and ...

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is composed of two materials, a plastic and an elastomer, whose dispersion characteristics (refractive index variation with wavelength) are different. We first designed the lens geometry and then used ray-tracing simulation, based on the Monte Carlo method, to analyze its performance from the point of view of both optical efficiency and the maximum attainable concentration. Afterwards, ADG Fresnel lens prototypes were manufactured using a simple and reliable method. It consists of a prior injection of plastic parts and a consecutive lamination, together with the elastomer and a glass substrate to fabricate the parquet of ADG Fresnel lenses. The accuracy of the manufactured lens profile is examined using an optical microscope while its optical performance is evaluated using a solar simulator for concentrator photovoltaic systems. The simulator is composed of a xenon flash lamp whose emitted light is reflected by a parabolic mirror. The collimated light has a spectral distribution and an angular aperture similar to the real Sun. We were able to assess the optical performance of the ADG Fresnel lenses by taking photographs of the irradiance spot cast by the lens using a charge-coupled device (CCD) camera and measuring the photocurrent generated by several types of multi junction (MJ) solar cells, which have been previously characterized at a solar simulator for concentrator solar cells. These measurements have demonstrated the achromatic behavior of ADG Fresnel lenses and, as a consequence, the suitability of the modelling and manufacturing methods.

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass ADG Fresnel Lens for Concentrating Photovoltaics

The achromatic doublet on glass (ADG) Fresnel lens makes use of two materials with differing dispersion to reduce chromatic aberration and increase attainable concentration. In this paper, a protocol for the complete characterization of the ADG Fresnel lens is presented.