Name: method development for contactless resonant cavity dielectric spectroscopic studies of cellulosic paper
Uploaded: 2019-10-04T13:00:00
Description: Watch this Scientific Journal Video about Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper at JoVE.com

United States Government Publishing Office and the National Institute of Standards and Technology.

1. Setup of materials
<ol>
	<li>Record all manufacturing information provided with the ream of paper (e.g., basis weight, manufacturer&#39;s advertised PCW content, and manufacturer&#8217;s advertised brightness).</li>
	<li>Take an average of ten thickness measurements along a sheet from the ream, using a caliper.</li>
	<li>Identify the machine and cross directions of the sheet (i.e., the machine direction is the long dimension).</li>
	<li>Using a protractor identify and cut the paper along the desired strip&#160;angle...

<ol>
	<li>Marinissen, E. J., Zorian, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Test Conference, 2009. ITC 2009. International. , 1-11 (2009).</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> TAPPI/ANSI Method T 401 om-15, Fiber analysis of paper and paperboard. , (2015).</li><li>Jablonsky, M., 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=Cellulose+Fibre+Identification+through+Color+Vectors+of+Stained+Fibre.">Cellulose Fibre Identification through Color Vectors of Stained Fibre.</a> BioResources. 10 (3), 5845-5862 (2015).</li><li>El Omari, H., Zyane, A., Belfkira, A., Taourirte, M., Brouillette, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dielectric+Properties+of+Paper+Made+from+Pulps+Loaded+with+Ferroelectric+Particles.">Dielectric Properties of Paper Made from Pulps Loaded with Ferroelectric Particles.</a> Journal of Nanomaterials. 2016, 1-10 (2016).</li><li>Sahin, H. T., Arslan, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Study+on+Physical+and+Chemical+Properties+of+Cellulose+Paper+Immersed+in+Various+Solvent+Mixtures.">A Study on Physical and Chemical Properties of Cellulose Paper Immersed in Various Solvent Mixtures.</a> International Journal of Molecular Sciences. 9, 78-88 (2008).</li><li>Einfeldt, J., Kwasniewski, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+Different+Types+of+Cellulose+by+Dielectric+Spectroscopy.">Characterization of Different Types of Cellulose by Dielectric Spectroscopy.</a> Cellulose. 9, 225-238 (2002).</li><li>Zteeman, P. A. M., van Turnhout, J., Kremer, F., Schonhals, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dielectric+Protperties+of+Inhomogenous+Media.">Dielectric Protperties of Inhomogenous Media.</a> Broadband Dielectric Spectroscopy. , 495-522 (2003).</li><li>Kremer, F., Schonhals, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Broadband Dielectric Spectroscopy. , (2003).</li><li>Fenske, K., Misra, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dielectric+Materials+at+Microwave+Frequencies.">Dielectric Materials at Microwave Frequencies.</a> Applied Microwave &amp; Wireless. , 92-100 (2000).</li><li>Jonscher, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dielectric+Relaxation+in+Solids.">Dielectric Relaxation in Solids.</a> Journal of Physics D: Applied Physics. 32 (14), 57-70 (1999).</li><li>Simula, S., 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=Measurement+of+Dielectric+Properties+of+Paper.">Measurement of Dielectric Properties of Paper.</a> Journal of Imaging Science and Technology. 43 (5), 472-477 (1999).</li><li>Sundara-Rajan, K., Byrd, L., Mamishev, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moisture+Content+Estimation+in+Paper+Pulp+Using+Fringing+Field+Impedance+Spectroscopy.">Moisture Content Estimation in Paper Pulp Using Fringing Field Impedance Spectroscopy.</a> TAPPI Journal. 4 (2), 23-27 (2005).</li><li>Williams, N. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moisture+Leveling+in+Paper,+Wood,+Textiles+and+Other+Mixed+Dielectric+Sheets.">Moisture Leveling in Paper, Wood, Textiles and Other Mixed Dielectric Sheets.</a> The Journal of Microwave Power. 1 (3), 73-80 (1966).</li><li>Kombolias, M., 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=Non-Destructive+Analysis+of+Printing+Substrates+via+Resonant+Cavity+Broadband+Dielectric+Spectroscopy.">Non-Destructive Analysis of Printing Substrates via Resonant Cavity Broadband Dielectric Spectroscopy.</a> 254th American Chemical Society National Meeting. , (2017).</li><li>Kombolias, M., Obrzut, J., Montgomery, K., Postek, M., Poster, D., Obeng, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dielectric+Spectroscopic+Studies+of+Biological+Material+Evolution+and+Application+to+Paper.">Dielectric Spectroscopic Studies of Biological Material Evolution and Application to Paper.</a> TAPPI Journal. 17 (9), 501-505 (2018).</li><li>Kombolias, M., 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=Broadband+Dielectric+Spectroscopic+Studies+of+Biological+Material+Evolution+and+Application+to+Paper.">Broadband Dielectric Spectroscopic Studies of Biological Material Evolution and Application to Paper.</a> PaperCon 2018. , (2018).</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=Basics+of+Measuring+the+Dielectric+Properties+of+Materials.">Basics of Measuring the Dielectric Properties of Materials.</a> Keysight Technologies. 5989-2589, (2017).</li><li>Orloff, N. D., 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=Dielectric+Characterization+by+Microwave+Cavity+Perturbation+Corrected+for+Nonuniform+Fields.">Dielectric Characterization by Microwave Cavity Perturbation Corrected for Nonuniform Fields.</a> IEEE Transactions on Microwave Theory and Techniques. 62 (9), 2149-2159 (2014).</li><li>Obrzut, J., Emiroglu, C., Kirilov, O., Yang, Y., Elmquist, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+Conductance+of+Graphene+from+Non-Contact+Resonant+Cavity.">Surface Conductance of Graphene from Non-Contact Resonant Cavity.</a> Measurement. 87, 146-151 (2016).</li><li>IEC. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanomanufacturing-Key+control+characteristics+-+Part+6-4:+Graphene+-+Surface+conductance+measurement+using+resonant+cavity.">Nanomanufacturing-Key control characteristics - Part 6-4: Graphene - Surface conductance measurement using resonant cavity.</a> International Electrotechnical Commission: 2016. , (2016).</li><li>Thomas, J., Idris, N. A., Collings, D. 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T., Carroll, A., Akhmetova, L., Somerville, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-Time+Imaging+of+Cellulose+Reorientation+during+Cell+Wall+Expansion+in+Arabdopsis+roots.">Real-Time Imaging of Cellulose Reorientation during Cell Wall Expansion in Arabdopsis roots.</a> Plant Physiology. 152, 787-796 (2010).</li><li>Osaki, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quick+Determination+of+Dielectric+Anisotropy+of+Paper+Sheets+by+Means+of+Microwaves.">Quick Determination of Dielectric Anisotropy of Paper Sheets by Means of Microwaves.</a> Journal of Applied Polymer Science. 37, 527-540 (1989).</li><li>Osaki, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microwaves+Quickly+Determine+the+Fiber+Orientation+of+Paper.">Microwaves Quickly Determine the Fiber Orientation of Paper.</a> TAPPI Journal. 70, 105-108 (1987).</li><li>Kombolias, M., 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=Broadband+Dielectric+Spectroscopic+Studies+of+Cellulosic+Paper+Aging.">Broadband Dielectric Spectroscopic Studies of Cellulosic Paper Aging.</a> TAPPI Journal. 17 (9), (2018).</li><li>Einfeldt, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+Dielectric+Relaxation+Spectroscopy+to+the+Characterization+of+Cellulosic+Fibers.">Application of Dielectric Relaxation Spectroscopy to the Characterization of Cellulosic Fibers.</a> Chemical Fibers International. 51, 281-283 (2001).</li><li>Driscoll, 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=The+Dielectric+Properties+of+Paper+and+Board+and+Moisture+Profile+Correction+at+Radio+Frequency.">The Dielectric Properties of Paper and Board and Moisture Profile Correction at Radio Frequency.</a> Paper Technology and Industry. 17 (2), 71-75 (1976).</li><li>Havlinova, B., Katuscak, S., Petrovicova, M., Makova, A., Brezova, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Study+of+Mechanical+Properties+of+Papers+Exposed+to+Various+Methods+of+Accelerated+Ageing.+Part+I.+The+Effect+of+Heat+and+Humidity+on+Original+Wood-Pulp+Papers.">A Study of Mechanical Properties of Papers Exposed to Various Methods of Accelerated Ageing. Part I. The Effect of Heat and Humidity on Original Wood-Pulp Papers.</a> Journal of Cultural Heritage. 10, 222-231 (2009).</li><li>Zieba-Palus, J., Weselucha-Birczynska, A., Trzcinska, B., Kowalski, R., Moskal, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+Degraded+Papers+by+Infrared+and+Raman+Spectroscopy+for+Forensic+Purposes.">Analysis of Degraded Papers by Infrared and Raman Spectroscopy for Forensic Purposes.</a> Journal of Molecular Structure. 1140, 154-162 (2017).</li><li>Capitani, D., Di Tullio, V., Proietti, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+Magnetic+Resonance+to+Characterize+and+Monitor+Cultural+Heritage.">Nuclear Magnetic Resonance to Characterize and Monitor Cultural Heritage.</a> Progress in Nuclear Resonance Spectroscopy. 64, (2012).</li><li>Bajpai, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Recycling and deinking of recovered paper. 1st edn. , (2014).</li><li>Fernandes Diniz, J. 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M., Knappe, D. R. U., Nanny, M. A., Barlaz, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+Controlling+Alkylbenzene+Sorption+to+Municipal+Solid+Waste.">Factors Controlling Alkylbenzene Sorption to Municipal Solid Waste.</a> Environmental Science &amp; Technology. 35 (22), 4569-4576 (2001).</li><li>Ho, R., Mai, K. W., Horowitz, M. 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W., 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=Three-dimensional+integrated+circuits.">Three-dimensional integrated circuits.</a> IBM Journal of Research and Development. 50 (4.5), 491-506 (2006).</li><li>Jones, K., Benson, S., Roux, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+forensic+analysis+of+office+paper+using+carbon+isotope+ratio+mass+spectrometry+-+Part+1:+Understanding+the+background+population+and+homogeneity+of+paper+for+the+comparison+and+discrimination+of+samples.">The forensic analysis of office paper using carbon isotope ratio mass spectrometry - Part 1: Understanding the background population and homogeneity of paper for the comparison and discrimination of samples.</a> Forensic Science International. 231, 354-363 (2013).</li><li>Jones, K., Benson, S., Roux, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+forensic+analysis+of+office+paper+using+oxygen+isotope+ratio+mass+spectrometry.+Part+1:+Understanding+the+background+population+and+homogeneity+of+paper+for+the+comparison+and+discrimination+of+samples.">The forensic analysis of office paper using oxygen isotope ratio mass spectrometry. 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We have shown elsewhere that the presence of lignin content of fibers does significantly alter the dielectric behavior of manufactured papers15. Speciation is not only important in the QA/QC testing of modern papers but of great interest in the study of historical papers which were predominantly manufactured from non-wood plant sources, such as bamboo, hemp, flax, and papyrus. As shown in Figure 7, our technique can distinguish between non-wood plant sources (100% cot...

Paper is a sheeted, heterogenous, manufactured product comprised of cellulosic fibers, sizing agents, inorganic fillers, colorants, and water. The cellulose fibers may originate from a variety of plant sources; the raw material is then broken down through a combination of physical and/or chemical treatments to produce a workable pulp consisting primarily of cellulose fibers. The cellulose in the paper product may also be recovered secondary, or recycled fiber1. The TAPPI Method T 401, &#34;Fiber analysis of paper and paperboard,&#34;&#160;is currently the state of the art method for identifying fiber types and their ratios present within a paper sample and is utilized by many communities2. It is a manual, colorimetric technique reliant on the visual acuity of a specially trained human analyst to discern the constituent fiber types of a paper sample. Furthermore, sample preparation for the TAPPI 401 method is laborious and time consuming, requiring physical destruction and chemical degradation of the paper sample. Staining with specially prescribed reagents renders fiber samples subject to the effects of oxidation, making it difficult to archive samples for preservation or specimen banking. Thus, the results from TAPPI Method T 401 are subject to human interpretation and are directly dependent upon the visual discernment of an individual analyst, which varies based upon that individual&#8217;s level of experience and training, leading to inherent errors when comparing results between and within sample sets. Multiple sources of imprecision and inaccuracy are present as well3. Additionally, the TAPPI method is incapable of determining the quantity of secondary fiber or the relative age of paper samples4,5.
In contrast, the resonant cavity dielectric spectroscopy (RCDS) technique we describe in this article offers analytical capabilities that are well-suited for paper examinations. Dielectric spectroscopy probes the relaxation dynamics of dipoles and mobile charge carriers within a matrix in response to rapidly changing electromagnetic fields, such as microwaves. This involves molecular rotational reorientation, making RCDS particularly well-suited to examine the dynamics of molecules in confined spaces, such as the water adsorbed on the cellulose fibers imbedded within a sheet of paper. By using water as a probe molecule, RCDS simultaneously can extract information on the chemical environment and physical conformation of the cellulose polymer.
The chemical environment of the cellulose fibers influences the extent of hydrogen bonding with water molecules, hence the ease of motion in response to the fluctuating electromagnetic fields. The cellulosic environment is determined, in part, by the concentrations of hemicellulose and lignin in the paper analyte. Hemicellulose is a hydrophilic branched polymer of pentoses, while lignin is a hydrophobic, cross-linked, phenolic polymer. The amounts of hemicellulose and lignin in a paper fiber are a consequence of the paper-making process. Adsorbed water in paper partitions between the hydrophilic sites, and the hydrogen bonding within the cellulose polymer, especially with the adsorbed water molecules, influences the level of cross-linking within the cellulose structure, the level of polarizability, and the architecture of pores within the cellulose polymer5. The total dielectric response of a material is a vector sum of all the dipole moments within the system and can be distinguished via dielectric spectroscopy through the use of effective medium theories6,7. Similarly, the capacitance of a dielectric material is inversely proportional to its thickness; hence, resonant cavity dielectric spectroscopy is ideal to study sample-to-sample thickness reproducibility of ultra-thin films materials such as paper8,9,10. While there is a significant body of work pertaining to the use of dielectric spectroscopy techniques to study wood and cellulose products, the scope of those studies has been limited to paper manufacturability issues11,12,13. We have taken advantage of the anisotropic nature of paper to demonstrate the application of RCDS to testing paper beyond moisture and mechanical properties14,15,16 and to show that it yields numerical data that can be used in quality assurance techniques such as gauge capability studies and real-time statistical process control (SPC). The method also has inherent forensic capabilities and can be used to quantitatively confront environmental sustainability concerns, support economic interests, and detect altered and counterfeit documents.
Resonant cavity dielectric spectroscopy (RCDS) theory and technique 
RCDS is one of several dielectric spectroscopy techniques available17; it was chosen specifically because it is non-contact, non-destructive, and experimentally simple in comparison to other methods of dielectric spectroscopy. In contrast to other analytical techniques used to study the properties of paper, RCDS eliminates the need for duplicate sets of measurements to account for the two sides of a sample sheet18. The resonant microwave cavity technique has the advantage of being sensitive to both the surface and bulk conductivity. For example, the surface conductance of a sample material is determined by tracking a change in the quality factor (Q-Factor) of the cavity as a specimen is progressively inserted into the cavity in quantitative correlation with the specimen&#8217;s volume18,19,20. Conductivity can be obtained by simply dividing surface conductance by the specimen thickness. The surface conductance of a thin, sheeted material like paper functions as a proxy for the dielectric profile of a material under test (MUT), as it is directly proportional to the dielectric loss, &#949;&#34;, of the MUT18,19,20. Dielectric loss is an indication of how much heat is dissipated by a dielectric material when an electric field is applied across it; materials with greater conductance will have a higher dielectric loss value than less conductive materials.
Experimentally, the dielectric loss, &#949;&#34;, associated with the specimen&#39;s surface is extracted from the rate of decrease of cavity resonance quality factor (Q) (i.e., energy loss), with increasing volume of specimen19. The Q is determined at the resonant frequency f from the 3 dB width, &#916;f, of the resonant peak at the resonant frequency f, Q = &#916;f /f. This relation is quantitatively correlated with the slope of the line given by Equation 1 below, <img alt="Equation 1" src="/files/ftp_upload/59991/59991eq1.jpg" /> where &#160;represents the difference of the reciprocal of the Q-factor of the specimen from the Q-factor of the empty cavity, <img alt="Equation 2" src="/files/ftp_upload/59991/59991eq2.jpg" /> is the ratio of the volume of the inserted specimen to the volume of the empty cavity, and the line intercept, b&#34;, accounts for the non-uniform field in the specimen, as shown in Figure 119.
<img alt="Equation 3" src="/files/ftp_upload/59991/59991eq3.jpg" />&#160; &#160; (Equation 1)
In this article, we illustrate the broad utility of this technique by determining the ratios of fiber species (speciation), determining the relative age of naturally and artificially aged papers, and quantifying the recycled fiber content of white office copier paper analytes. Whereas the RCDS technique may be suitable for studying other topics, such as aging issues in paper insulation in electric power apparatus, such studies are outside the scope of the current work but would be interesting to pursue in the future.

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			<td height="21" style="height:21px;width:323px;">commercially produced colored office paper&#160;</td>
			<td style="width:255px;">Neenah Paper</td>
			<td style="width:161px;"></td>
			<td style="width:352px;">Purchased from Staples</td>
		</tr>
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			<td height="21" style="height:21px;width:323px;">Q-Lab QUV accelerated weathering chamber</td>
			<td>Q-Lab Corporation, Westlake, OH</td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:323px;">X-Rite eXact&#160;</td>
			<td>X-Rite, Inc., Grand Rapids, MI</td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Agilent N5225A network analyzer&#160;</td>
			<td>Agilent Technologies, Santa Rosa, CA</td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
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			<td height="25" style="height:25px;width:323px;">WR90 rectangular waveguide&#160;</td>
			<td>Agilent Technologies, Santa Rosa, CA</td>
			<td style="width:161px;"></td>
			<td>R 100 (a = 10.16 mm, b = 22.86 mm, lz =127.0mm)&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:323px;">JMP data analysis software</td>
			<td style="width:255px;">SAS, Cary, NC</td>
			<td style="width:161px;"></td>
			<td></td>
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method development for contactless resonant cavity dielectric spectroscopic studies of cellulosic paper

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of data that can be obtained from an individual sample and renders it difficult to produce statistically relevant data for unique and rare materials. Resonant cavity dielectric spectroscopy is a non-destructive, contactless technique which can simultaneously interrogate both sides of a sheeted material and provide measurements which are suitable for statistical interpretations. This offers analysts the ability to quickly discriminate between sheeted materials based on composition and storage history. In this methodology article, we demonstrate how contactless resonant cavity dielectric spectroscopy may be used to differentiate between paper analytes of varying fiber species compositions, to determine the relative age of the paper, and to detect and quantify the amount of post-consumer waste (PCW) recycled fiber content in manufactured office paper.

Rationale for choosing the 60&#176; strip angle 
The cut orientation of the test sample influences the magnitude of the dielectric response, as shown in the graph in Figure 2. In initial experiments, test strips were cut from the orthogonal angles of the sheet, as is standard practice for measuring physical properties in paper science; however, strips cut from non-orthogonal angles along the paper sheet have provided the greatest resolution between paper types, particul...

Watch this Scientific Journal Video about Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper at JoVE.com

Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper

A protocol for the non-destructive analysis of the fiber content and relative age of paper.

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of ...

This method provides an objective, machine-repeatable alternative to performing traditional fiber analysis of paper, and it exceeds the metrological limits of traditional fiber analysis. Unlike traditional fiber analysis, it is quick, contactless, nondestructive, and requires no specialized training, nor is it dependent on the visual acuity of an individual analyst. Record all manufacturing information provided with the ream of paper, such as basis weight, manufacturer's advertised post-consumer waste content, and manufacturer's advertised brightness.Wear gloves, and perform handling with tweezers to avoid creasing and contaminating the paper samples. Take an average of 10 thickness measurements along a sheet from the ream, using a caliper. Identify the machine and cross directions of the sheet.Using a protractor, identify and cut the paper along the desired strip angle between the machine and cross directions. Using a rotary cutter, slice test strips 0.5 centimeters wide by eight centimeters long in the target orientation for the sample. Label samples from one end, and store between glass microscopy slides.Store under nitrogen atmosphere until testing. Perform accelerated paper fade testing as described in the text protocol. Cut sample strips out of the aged paper samples to fit the resonant cavity.The typical specimen area is 0.5 centimeters by eight centimeters. The resonant cavity testing fixture consists of an air-filled standard WR-90 rectangular waveguide. Record the temperature and relative humidity.Take the initial reading of the quality factor, Q-naught, and the resonant frequency, f-naught, of the empty cavity. Now, position the specimen secured in the sample holder above the slot at the center of the cavity. During the measurements, the specimen is inserted into the cavity through the slot in steps of increasing volume, where volume is equal to the height of the inserted sample times the sample width times the sample thickness.Using the Vernier caliper on the sample mount, insert the sample into the cavity by 50-micron increments. Take readings of the quality factor and resonant frequency at each step until the sample has been lowered 10 millimeters into the cavity. Retract the sample from the interior at the same increments of 50 microns.Take readings of the quality factor and resonant frequency until the sample has been fully retracted. Store the sample between glass slides, and return them to nitrogen atmosphere. The dielectric loss of the paper samples is obtained from the slope of the perturbation.The cut orientation of the test sample influences the magnitude of the dielectric response. A comparison of dielectric response by strip angle is shown for virgin, as-received, blue, 24-pound office papers before and after UV fading for 169 hours. Strips cut from non-orthogonal angles along the paper sheet have provided the greatest resolution between paper types, particularly at the 45-degree and 60-degree orientations.Dielectric loss profiles of cotton-containing bond papers procured by the U.S.Federal Government using 60-degree strips show that different concentrations of cotton fiber can be distinguished. The results of testing 100%cotton bond paper procured by the Federal Government were compared at 46%relative humidity and 49%relative humidity. After 169 hours of UV-accelerated aging, the degradation of the cellulose polymer is discernible as the average dielectric loss values had decreased for both the virgin and recycled varieties.It is notable that the technique can distinguish between the virgin and recycled materials even after the accelerated aging period. A contour plot-based linear regression fit shows the dielectric loss of white office copier paper based upon the manufacturer's advertised brightness and recycled waste paper content of the analytes. The most important thing to remember when attempting this procedure is to maintain consistent laboratory temperature and humidity conditions.This method has great promise and direct utility not just to the pulp and paper industry but also to secure credential manufacturing, forensics, customs enforcement, and archaeology and conservation science.

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Research

JoVE Journal

Engineering

Construction and Characterization of External Cavity Diode Lasers for Atomic Physics

Since their development in the late 1980s, cheap, reliable external cavity diode lasers (ECDLs) have replaced complex and expensive traditional dye and Titanium Sapphire lasers as the workhorse laser of atomic physics labs1,2. Their versatility and prolific use throughout atomic physics in applications such as absorption spectroscopy and laser cooling1,2 makes it imperative for incoming students to gain a firm practical understanding of these lasers. This publication builds upon the seminal work by Wieman3, updating components, and providing a video tutorial. The setup, frequency locking and performance characterization of an ECDL will be described. Discussion of component selection and proper mounting of both diodes and gratings, the factors affecting mode selection within the cavity, proper alignment for optimal external feedback, optics setup for coarse and fine frequency sensitive measurements, a brief overview of laser locking techniques, and laser linewidth measurements are included.

This is an instructional paper to guide the construction and diagnostics of external cavity diode lasers (ECDLs), including component selection and optical alignment, as well as the basics of frequency reference spectroscopy and laser linewidth measurements for applications in the field of atomic physics.

Since their development in the late 1980s, cheap, reliable external cavity diode lasers (ECDLs) have replaced complex and expensive traditional dye and ...

Real-Time DC-dynamic Biasing Method for Switching Time Improvement in Severely Underdamped Fringing-field Electrostatic MEMS Actuators

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input bias voltage. However, the tradeoff for the improved switching performance is a relatively long settling time to reach each gap height in response to various applied voltages. Transient applied bias waveforms are employed to facilitate reduced switching times for electrostatic fringing-field MEMS actuators with high mechanical quality factors. Removing the underlying substrate of the fringing-field actuator creates the low mechanical damping environment necessary to effectively test the concept. The removal of the underlying substrate also a has substantial improvement on the reliability performance of the device in regards to failure due to stiction. Although DC-dynamic biasing is useful in improving settling time, the required slew rates for typical MEMS devices may place aggressive requirements on the charge pumps for fully-integrated on-chip designs. Additionally, there may be challenges integrating the substrate removal step into the back-end-of-line commercial CMOS processing steps. Experimental validation of fabricated actuators demonstrates an improvement of 50x in switching time when compared to conventional step biasing results. Compared to theoretical calculations, the experimental results are in good agreement.

The robust device design of fringing-field electrostatic MEMS actuators results in inherently low squeeze-film damping conditions and long settling times when performing switching operations using conventional step biasing. Real-time switching time improvement with DC-dynamic waveforms reduces the settling time of fringing-field MEMS actuators when transitioning between up-to-down and down-to-up states.

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input ...

The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and polar dielectric liquids. These bridges are unique from capillary bridges in that they exhibit extensibility beyond a few millimeters, have complex bi-directional mass transfer patterns, and emit non-Planck infrared radiation. A number of common solvents can form such bridges as well as low conductivity solutions and colloidal suspensions. The macroscopic behavior is governed by electrohydrodynamics and provides a means of studying fluid flow phenomena without the presence of rigid walls. Prior to the onset of a liquid bridge several important phenomena can be observed including advancing meniscus height (electrowetting), bulk fluid circulation (the Sumoto effect), and the ejection of charged droplets (electrospray). The interaction between surface, polarization, and displacement forces can be directly examined by varying applied voltage and bridge length. The electric field, assisted by gravity, stabilizes the liquid bridge against Rayleigh-Plateau instabilities. Construction of basic apparatus for both vertical and horizontal orientation along with operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

Horizontal and vertical electrohydrodynamic liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields and polar dielectric liquids. The construction of basic apparatus and operational examples, including thermographic images, for three liquids (e.g., water, DMSO, and glycerol) is presented.

Horizontal and vertical liquid bridges are simple and powerful tools for exploring the interaction of high intensity electric fields (8-20 kV/cm) and ...

Fabrication Process of Silicone-based Dielectric Elastomer Actuators

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an elastomeric dielectric membrane sandwiched between two compliant electrodes. The large actuation strains of these transducers when used as actuators (over 300% area strain) and their soft and compliant nature has been exploited for a wide range of applications, including electrically tunable optics, haptic feedback devices, wave-energy harvesting, deformable cell-culture devices, compliant grippers, and propulsion of a bio-inspired fish-like airship. In most cases, DETs are made with a commercial proprietary acrylic elastomer and with hand-applied electrodes of carbon powder or carbon grease. This combination leads to non-reproducible and slow actuators exhibiting viscoelastic creep and a short lifetime. We present here a complete process flow for the reproducible fabrication of DETs based on thin elastomeric silicone films, including casting of thin silicone membranes, membrane release and prestretching, patterning of robust compliant electrodes, assembly and testing. The membranes are cast on flexible polyethylene terephthalate (PET) substrates coated with a water-soluble sacrificial layer for ease of release. The electrodes consist of carbon black particles dispersed into a silicone matrix and patterned using a stamping technique, which leads to precisely-defined compliant electrodes that present a high adhesion to the dielectric membrane on which they are applied.

This manuscript shows the fabrication process for the manufacture of dielectric elastomer soft actuators based on silicone membranes. The three key stages of production are presented in detail: blade casting of thin silicone membranes; pad printing of compliant electrodes; and the assembly of all the components.

This contribution demonstrates the fabrication process of dielectric elastomer transducers (DETs). DETs are stretchable capacitors consisting of an ...

Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the degradation of device performance. In order to evaluate such degradations using computer simulations, full matrix material properties at elevated temperatures are needed as inputs. It is extremely difficult to measure such data for ferroelectric materials due to their strong anisotropic nature and property variation among samples of different geometries. Because the degree of depolarization is boundary condition dependent, data obtained by the IEEE (Institute of Electrical and Electronics Engineers) impedance resonance technique, which requires several samples with drastically different geometries, usually lack self-consistency. The resonant ultrasound spectroscopy (RUS) technique allows the full set material constants to be measured using only one sample, which can eliminate errors caused by sample to sample variation. A detailed RUS procedure is demonstrated here using a lead zirconate titanate (PZT-4) piezoceramic sample. In the example, the complete set of material constants was measured from room temperature to 120 &#176;C. Measured free dielectric constants <img alt="Equation 1" src="/files/ftp_upload/53461/image001.jpg" /> and&#160;<img alt="Equation 2" src="/files/ftp_upload/53461/image002.jpg" /> were compared with calculated ones based on the measured full set data, and piezoelectric constants d15 and d33 were also calculated using different formulas. Excellent agreement was found in the entire range of temperatures, which confirmed the self-consistency of the data set obtained by the RUS.

This protocol describes the procedure of measuring the temperature dependence of the full set material constants of piezoelectric materials using resonant ultrasound spectroscopy (RUS).

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the ...

Emission Spectroscopic Boundary Layer Investigation during Ablative Material Testing in Plasmatron

Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution for future high-speed reentry missions. But despite the advancements made since Apollo, heat flux prediction remains an imperfect science and engineers resort to safety factors to determine the TPS thickness. This goes at the expense of embarked payload, hampering, for example, sample return missions. 
Ground testing in plasma wind-tunnels is currently the only affordable possibility for both material qualification and validation of material response codes. The subsonic 1.2MW Inductively Coupled Plasmatron facility at the von Karman Institute for Fluid Dynamics is able to reproduce a wide range of reentry environments. This protocol describes a procedure for the study of the gas/surface interaction on ablative materials in high enthalpy flows and presents sample results of a non-pyrolyzing, ablating carbon fiber precursor. With this publication, the authors envisage the definition of a standard procedure, facilitating comparison with other laboratories and contributing to ongoing efforts to improve heat shield reliability and reduce design uncertainties.
The described core techniques are non-intrusive methods to track the material recession with a high-speed camera along with the chemistry in the reactive boundary layer, probed by emission spectroscopy. Although optical emission spectroscopy is limited to line-of-sight measurements and is further constrained to electronically excited atoms and molecules, its simplicity and broad applicability still make it the technique of choice for analysis of the reactive boundary layer. Recession of the ablating sample further requires that the distance of the measurement location with respect to the surface is known at all times during the experiment. Calibration of the optical system of the applied three spectrometers allowed quantitative comparison. At the fiber scale, results from a post-test microscopy analysis are presented.

Development of new ablative materials and their numerical modeling requires extensive experimental investigation. This protocol describes procedures for material response characterization in plasma flows with the core techniques being non-intrusive methods to track the material recession along with the chemistry in the reactive boundary layer by emission spectroscopy.

Ablative Thermal Protection Systems (TPS) allowed the first humans to safely return to Earth from the moon and are still considered as the only solution ...

Optical Trap Loading of Dielectric Microparticles In Air

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly scattered dielectric microparticles adhered to a glass substrate are momentarily detached using ultrasonic vibrations generated by a piezoelectric transducer (PZT). Then, the optical beam focused on a selected particle lifts it up to the optical trap while the vibrationally excited microparticles fall back to the substrate. A particle may be trapped at the nominal focus of the trapping beam or at a position above the focus (referred to here as the levitation position) where gravity provides the restoring force. After the measurement, the trapped particle can be placed at a desired position on the substrate in a controlled manner. 
In this protocol, an experimental procedure for selective optical trap loading in air is outlined. First, the experimental setup is briefly introduced. Second, the design and fabrication of a PZT holder and a sample enclosure are illustrated in detail. The optical trap loading of a selected microparticle is then demonstrated with step-by-step instructions including sample preparation, launching into the trap, and use of electrostatic force to excite particle motion in the trap and measure charge. Finally, we present recorded particle trajectories of Brownian and ballistic motions of a trapped microparticle in air. These trajectories can be used to measure stiffness or to verify optical alignment through time domain and frequency domain analysis. Selective trap loading enables optical tweezers to track a particle and its changes over repeated trap loadings in a reversible manner, thereby enabling studies of particle-surface interaction.

A protocol for launching and stably trapping selected dielectric microparticles in air is presented.

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly ...

Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation

We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using femtosecond laser-induced ablation. We show that thousands of periodic nano-craters are fabricated on an optical nanofiber by irradiating with just a single femtosecond laser pulse. For a typical sample, periodic nano-craters with a period of 350 nm and with diameter gradually varying from 50 - 250 nm over a length of 1 mm are fabricated on a nanofiber with diameter around 450 - 550 nm. A key aspect of such a nanofabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. Moreover, the single-shot fabrication makes it immune to mechanical instabilities and other fabrication imperfections. Such periodic nano-craters on nanofiber, act as a 1-D PhC and enable strong and broadband reflection while maintaining the high transmission out of the stopband. We also present a method to control the profile of the nano-crater array to fabricate apodized and defect-induced PhC cavities on the nanofiber. The strong confinement of the field, both transverse and longitudinal, in the nanofiber-based PhC cavities and the efficient integration to the fiber networks, may open new possibilities for nanophotonic applications and quantum information science.

We present a protocol for fabricating 1-D photonic crystal cavities on subwavelength diameter silica fibers (optical nanofibers) using femtosecond laser-induced ablation.

We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using ...

Dielectric RheoSANS &#8212; Simultaneous Interrogation of Impedance, Rheology and Small Angle Neutron Scattering of Complex Fluids

A procedure for the operation of a new dielectric RheoSANS instrument capable of simultaneous interrogation of the electrical, mechanical and microstructural properties of complex fluids is presented. The instrument consists of a Couette geometry contained within a modified forced convection oven mounted on a commercial rheometer. This instrument is available for use on the small angle neutron scattering (SANS) beamlines at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). The Couette geometry is machined to be transparent to neutrons and provides for measurement of the electrical properties and microstructural properties of a sample confined between titanium cylinders while the sample undergoes arbitrary deformation. Synchronization of these measurements is enabled through the use of a customizable program that monitors and controls the execution of predetermined experimental protocols. Described here is a protocol to perform a flow sweep experiment where the shear rate is logarithmically stepped from a maximum value to a minimum value holding at each step for a specified period of time while frequency dependent dielectric measurements are made. Representative results are shown from a sample consisting of a gel composed of carbon black aggregates dispersed in propylene carbonate. As the gel undergoes steady shear, the carbon black network is mechanically deformed, which causes an initial decrease in conductivity associated with the breaking of bonds comprising the carbon black network. However, at higher shear rates, the conductivity recovers associated with the onset of shear thickening. Overall, these results demonstrate the utility of the simultaneous measurement of the rheo-electro-microstructural properties of these suspensions using the dielectric RheoSANS geometry.

Dielectric RheoSANS &amp;#8212; Simultaneous Interrogation of Impedance, Rheology and Small Angle Neutron Scattering of Complex Fluids

Here, we present a procedure for the measurement of simultaneous impedance, rheology and neutron scattering from soft matter materials under shear flow.

A procedure for the operation of a new dielectric RheoSANS instrument capable of simultaneous interrogation of the electrical, mechanical and ...

Fabrication of an Optical Cell Dryer for the Spectroscopic Analysis Cells

Optical cells, which are experimental instruments, are small, square tubes sealed on one side. A sample is placed in this tube, and a measurement is performed with a spectroscope. The materials used for optical cells generally include quartz glass or plastic, but expensive quartz glass is reused by removing substances, other than liquids, to be analyzed that adhere to the interior of the container. In such a case, the optical cells are washed with water or ethanol and dried. Then, the next sample is added and measured. Optical cells are dried naturally or with a manual hairdryer. However, drying takes time, which makes it one of the factors that increase the experiment time. In this study, the objective is to drastically reduce the drying time with a dedicated automatic dryer that can dry multiple optical cells at once. To realize this, a circuit was designed for a microcomputer, and the hardware using it was independently designed and manufactured.

A protocol for fabricating a device for simultaneously drying multiple optical cells is presented.

Optical cells, which are experimental instruments, are small, square tubes sealed on one side. A sample is placed in this tube, and a measurement is ...