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. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pontamine+Fast+Scarlet+4B+Bifluorescence+and+Measurement+of+Cellulose+Microfibril+Angles.">Pontamine Fast Scarlet 4B Bifluorescence and Measurement of Cellulose Microfibril Angles.</a> Journal of Microscopy. 268 (1), 13-27 (2017).</li><li>Anderson, C. 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. M. B., Gil, M. H., Castro, J. A. A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hornification-its+origin+and+interpretation+in+wood+pulps.">Hornification-its origin and interpretation in wood pulps.</a> Wood Science and Technology. 37, 489-494 (2004).</li><li>Cao, B., Tschirner, U., Ramaswamy, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+pulp+chemical+composition+on+recycling.">Impact of pulp chemical composition on recycling.</a> TAPPI Journal. 81 (12), 119-127 (1998).</li><li>Saukkonen, E., 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=Effect+of+the+carbohydrate+composition+of+bleached+kraft+pulp+on+the+dielectric+and+electrical+properties+of+paper.">Effect of the carbohydrate composition of bleached kraft pulp on the dielectric and electrical properties of paper.</a> Cellulose. 22 (2), 1003-1017 (2015).</li><li>Wu, B., Taylor, C. 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. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+future+of+wires.">The future of wires.</a> Proceedings of the IEEE. 89 (4), 490-504 (2001).</li><li>Aoki, 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=In+Evaluation+of+back+end+of+line+structures+underneath+wirebond+pads+in+ultra+low-k+device.">In Evaluation of back end of line structures underneath wirebond pads in ultra low-k device.</a> Electronic Components and Technology Conference (ECTC), IEEE 62nd. , 1097-1102 (2012).</li><li>Rantanen, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identificaiton+of+Secondary+Fiber+in+Paper.">Identificaiton of Secondary Fiber in Paper.</a> Progress in Paper Recycling. , 77-79 (1994).</li><li>Topol, A. 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. Part 1: Understanding the background population and homogeneity of paper for the comparison and discrimination of samples.</a> Forensic Science International. 262, 97-107 (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=Recycled+Paper+Research+at+the+Library+of+Congress.">Recycled Paper Research at the Library of Congress.</a> Library of Congress. , (2014).</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=TAPPI+550+om-13:+Determination+of+Equilibrium+Moisture+in+Pulp,+Paper+and+Paperboard+for+Chemical+Analysis.">TAPPI 550 om-13: Determination of Equilibrium Moisture in Pulp, Paper and Paperboard for Chemical Analysis.</a> TAPPI. , (2013).</li></ol>

This is a contribution of the National Institute of Standards and Technology, and not subject to copyright. Certain commercial equipment, instruments, or materials are identified in this report to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology or the United States Government Publishing Office, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose. The authors have nothing to disclose.

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.

<table border="0" cellpadding="0" cellspacing="0" style="width:1091px;" width="1091">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<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>
		<tr height="21">
			<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>
		<tr height="25">
			<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>
		</tr>
	</tbody>
</table>

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.

method-development-for-contactless-resonant-cavity-dielectric

Research

JoVE Journal

Engineering

5.9K vues.  United States Government Publishing Office. Cette méthode fournit une alternative objective et reproductible à l’exécution de l’analyse traditionnelle des fibres de papier, et elle dépasse les limites métrologiques de l’analyse traditionnelle des fibres. Contrairement à l’analyse traditionnelle des fibres, elle est rapide, sans contact, non constructive et ne nécessite aucune formation spécialisée, ni dépend de l’acuité visuelle d’un analyste individuel. Enregistrez toutes les informations de fabrication fournies...