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`UNITED STATES PATENT AND TRADEMARK OFFICE
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`BEFORE THE PATENT TRIAL AND APPEAL BOARD
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`GENERAL ELECTRIC COMPANY, Petitioner,
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`v.
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`UNITED TECHNOLOGIES CORPORATION, Patent Owner
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`Case IPR2016-00962
`Patent No. 9,121,412
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`DECLARATION OF DR. K. MATHIOUDAKIS
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`GE v. UTC
`Trial IPR2016-00952
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`UTC-2015.001
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`Case IPR2016-00962
`Patent No. 9,121,412
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`I, Dr. K. Mathioudakis, declare as follows:
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`I.
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`INTRODUCTION
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`1.
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`I have been retained by Patent Owner, United Technologies
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`Corporation, as an independent expert and technical consultant in this proceeding
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`before the United States Patent and Trademark Office. Although I am being
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`compensated at a rate of €380 per hour for the time I spend on this matter, no part
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`of my compensation depends on the outcome of this proceeding. I have no other
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`interest in this proceeding.
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`II. QUALIFICATIONS
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`2.
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`I have been a Professor in the Department of Mechanical Engineering
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`for the past ten years, and the Director of the Laboratory of Thermal
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`Turbomachines at the National Technical University of Athens (NTUA), Greece.
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`My research interests include investigations into the areas of turbomachinery
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`performance and modelling, as well as energy conversion through thermal
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`machines. I have taught courses that cover, among other things, gas and steam
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`turbine operation, jet engines and their performance, and gas turbine diagnostics.
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`3.
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`I have conducted research on aircraft engine performance modelling,
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`engine condition monitoring, component fault diagnosis, aircraft engine emissions,
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`2
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`UTC-2015.002
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`Case IPR2016-00962
`Patent No. 9,121,412
`aircraft mission analysis, and flow in the turbomachinery components of aircraft
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`engines.
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`4.
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`I received an undergraduate degree in Mechanical Engineering in
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`1980 from NTUA and a post-graduate degree in Fluid Dynamics from the Von
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`Karman Institute for Fluid Dynamics, Belgium, in 1981, with Honors. I obtained a
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`Doctorate in Applied Sciences with “the highest distinction,” from the Catholic
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`University of Leuven, Belgium, in 1985. From 1987 to the present, I have held
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`various faculty positions at NTUA, including Research Associate in the Laboratory
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`of Thermal Turbomachines, Lecturer, Assistant Professor, and Associate Professor.
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`From 2009 to 2015, I held the position of Secretary General in the Ministry of
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`Environment, Energy, and Climate Change.
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`5.
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`I have published many articles relating to turbomachinery flow
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`measurements, gas turbine health and performance assessment, analyses of
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`turbofan engines, and heat transfer in turbomachinery, including articles related to
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`geared turbofan engines. From 2004 to 2008, I served as the Vice Chairman and
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`Chairman of the Controls and Diagnostics Committee, International Gas Turbine
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`Institute of the ASME. The Institute is dedicated to supporting the international
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`exchange and development of information to improve the design, application,
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`3
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`UTC-2015.003
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`Case IPR2016-00962
`Patent No. 9,121,412
`manufacture, operation and maintenance, and environmental impact of all types of
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`gas turbines, turbomachinery, and related equipment.
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`6.
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`A full listing of my publications is included in my curriculum vitae,
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`which I understand has been filed as an exhibit in this proceeding.
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`III. MATERIALS CONSIDERED
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`7.
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`I understand that this proceeding involves U.S. Patent No. 9,121,412.
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`In forming my opinions, I have considered, among other things, a Petition for Inter
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`Partes Review of claims 1, 2, 4, 5, 7, 8, and 11 filed by General Electric Company
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`(“Petitioner”) dated April 25, 2016, and related exhibits (including the declaration
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`of Dr. Reza Abhari (GE-1003)), an Institution Decision issued by the Patent Trial
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`and Appeal Board on October 27, 2016, and the deposition transcript of Dr. Abhari
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`(UTC-2013), and related exhibits. I have also considered the ’412 patent (GE-
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`1001) and its file history, the Patent Owner’s Preliminary Response, and the
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`exhibits and materials referenced in this declaration. I have also considered the
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`following:
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`• Exhibit UTC-2001. It appears to be a true and correct copy of an article by
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`L. Thompson, entitled Gamechanger: How Pratt & Whitney Transformed
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`Itself To Lead A Revolution In Jet Propulsion, published by Forbes (Jan. 21,
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`2016), available at
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`4
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`UTC-2015.004
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`Case IPR2016-00962
`Patent No. 9,121,412
`http://www.forbes.com/sites/lorenthompson/2016/01/21/gamechanger-how-
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`
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`pratt-whitney-transformed-itself-to-lead-a-revolution-in-jet-
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`propulsion/#49e1af53a9e9;
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`• Exhibit UTC-2002. It appears to be a true and correct copy of an article by
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`T. K. Grose, entitled Reshaping Flight for Fuel Efficiency: Five
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`Technologies on the Runway, published by NATIONAL GEOGRAPHIC
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`(Apr. 23, 2013), available at
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`http://news.nationalgeographic.com/news/energy/2013/04/130423-
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`reshaping-flight-for-fuel-efficiency/;
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`• Exhibit UTC-2003. It appears to be a true and correct copy of an article by
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`L. Krauskopf, entitled GE Exec says avoided geared design in jet engine
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`battle with Pratt, published by REUTERS (Sept. 15, 2014), available at
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`http://www.reuters.com/article/us-general-electric-united-tech-engine-
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`idUSKBN0HA2H620140915;
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`• Exhibit UTC-2004. It appears to be a true and correct copy of an article by
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`D. Tsang, entitled Special Report: The Engine Battle Heats Up (Update 1),
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`published by ASPIRE AVIATION (May 10, 2011), available at
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`http://www.aspireaviation.com/2011/05/10/pw-purepower-engine-vs-cfm-
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`leap-x/;
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`5
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`UTC-2015.005
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`Case IPR2016-00962
`Patent No. 9,121,412
`• Exhibit UTC-2005. It appears to be a true and correct copy of an article by
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`D. Gates, entitled Bombardier flies at higher market, published by THE
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`SEATTLE TIMES (July 13, 2008), available at
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`http://old.seattletimes.com/html/businesstechnology/2008048666_farnborou
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`ghside13.html;
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`• Exhibit UTC-2006. It appears to be a true and correct copy of excerpts from
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`a textbook by S.L. Dixon, entitled Fluid Mechanics and Thermodynamics of
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`Turbomachinery (5th ed. 1998);
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`• Exhibit UTC-2007. It appears to be a true and correct copy of an article by
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`A. Epstein, entitled Aeropropulsion for Commercial Aviation in the Twenty-
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`First Century and Research Directions Needed, 52 AIAA J. 5 (May 2014);
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`• Exhibit UTC-2009. It appears to be a true and correct copy of an article by
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`P.R. Gliebe and B.A. Janardan, entitled Ultra-High Bypass Engine
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`Aeroacoustic Study, NASA/CR-2003-212525 (Oct. 2003);
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`• Exhibit UTC-2010. It appears to be a true and correct copy of an article by
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`G. Knip, entitled Analysis of an Advanced Technology Subsonic Turbofan
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`Incorporating Revolutionary Materials, NASA Technical Memorandum
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`89868 (May 1987);
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`6
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`UTC-2015.006
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`Case IPR2016-00962
`Patent No. 9,121,412
`• Exhibit UTC-2011. It appears to be a true and correct copy of an article by
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`C. Hall and D. Crichton, entitled Engine Design Studies for a Silent Aircraft,
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`129 J. Turbomachinery, 479 (July 2007);
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`• Exhibit UTC-2012. It appears to be a true and correct copy of excerpts from
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`a book by J.D. Mattingly, entitled Elements of Propulsion Gas Turbines and
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`Rockets, (1996), Chapter 5.10 Ideal Turbofan with Optimum Bypass Ratio,
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`pp. 299-305;
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`• Exhibit UTC-2013. It appears to be a true and correct copy of the
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`Deposition Transcript of Dr. Reza Abhari, Ph.D. (January 4, 2017);
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`• Exhibit UTC-2014. It appears to be a true and correct copy of a report
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`submitted by Pratt & Whitney to the Federal Aviation Administration,
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`entitled Evaluation of ARA Catalytic Hydrothermolysis (CH) Fuel:
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`Continuous Lower Energy, Emissions and Noise (CLEEN) Program, FR-
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`27652-2 Rev. 1 (April 30, 2014);
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`• Exhibit UTC-2016. It appears to be a true and correct copy of an article by
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`M.J. Benzakein, entitled Propulsion Strategy for the 21st Century—A Vision
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`into the Future, ISABE 2001-1005 (2001);
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`7
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`UTC-2015.007
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`Case IPR2016-00962
`Patent No. 9,121,412
`• Exhibit UTC-2017. It appears to be a true and correct copy of excerpts from
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`a book by J.D. Mattingly, entitled Elements of Propulsion Gas Turbines and
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`Rockets, (2006);
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`• Exhibit UTC-2018. It appears to be a true and correct copy of excerpts from
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`a book by J.H. Horlock, entitled Axial Flow Compressors: Fluid Mechanics
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`and Thermodynamics (1958);
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`• Exhibit UTC-2019. It appears to be a true and correct copy of a report by
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`NASA, entitled Aerodynamic Design of Axial-Flow Compressors (1965);
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`• Exhibit UTC-2020. It appears to be a true and correct copy of excerpts from
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`a book by R.D. Flack, entitled Fundamentals of Jet Propulsion with
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`Applications (2005);
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`• Exhibit UTC-2021. It appears to be a true and correct copy of an article by
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`M.D. Guynn, J.J. Berton, K.L. Fisher, et al., entitled Analysis of Turbofan
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`Design Options for an Advanced Single-Aisle Transport Aircraft, AIAA
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`2009-6942 (2009);
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`• Exhibit UTC-2022. It appears to be a true and correct copy of an article by
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`L. Xu and T. Gronstedt, entitled Design and Analysis of an Intercooled
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`Turbofan Engine, J. Engineering for Gas Turbines & Power (Nov. 2010);
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`8
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`UTC-2015.008
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`Case IPR2016-00962
`Patent No. 9,121,412
`• Exhibit UTC-2023. It appears to be a true and correct copy of an excerpt
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`from a book by J.L. Kerrebrock, entitled Aircraft Engines and Gas Turbines,
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`(2d ed. 1992);
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`• Exhibit UTC-2024. It appears to be a true and correct copy of an excerpt
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`from a book by P.G. Hill and C.R. Peterson, entitled Mechanics and
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`Thermodynamics of Propulsion (2d ed. 2010); and
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`• Exhibit UTC-2025. It appears to be a true and correct copy of an article by
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`M.D. Guynn, J.J. Berton, M.T. Tong, et al., entitled Advanced Single-Aisle
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`Transport Propulsion Design Options Revisited, AIAA 2013-4330 (2013).
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`IV. RELEVANT LEGAL STANDARDS
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`8.
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`I have been asked to provide my opinions on whether the Petition and
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`the accompanying exhibits (GE-1002 to GE-1023) disclose or render obvious the
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`elements of claims 1, 2, 4, 5, 7, 8, and 11 of the ’412 patent to one of ordinary skill
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`in the art in the 2011 timeframe. I understand that July 5, 2011 is the priority date
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`of the ’412 patent. The opinions I express in this declaration are therefore from the
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`perspective of one of ordinary skill in the art of turbofan engines in the 2011 time
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`period. Based on discussions with Patent Owner’s counsel, I understand that the
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`following legal principles apply in this proceeding.
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`9
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`UTC-2015.009
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`Case IPR2016-00962
`Patent No. 9,121,412
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`A. Unpatentable Subject Matter
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`9.
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`Counsel has informed me that this proceeding will focus primarily on
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`whether claims 1, 2, 4, 5, 7, 8, and 11 cover unpatentable subject matter. In
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`particular, to show the unpatentability of any claim of the ’412 patent, I understand
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`Petitioner has the burden of showing that the subject matter recited in the claims
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`was either anticipated or obvious in light of the prior art and the knowledge of a
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`person of ordinary skill in the art at the time of invention.
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`10.
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`I understand that the subject matter of a patent claim is anticipated
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`when a single item of prior art teaches each and every element recited in the claim.
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`The prior art also needs to disclose the elements as they are arranged in the claim.
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`Merely disclosing the elements is not enough. Moreover, the disclosure must
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`enable a person of ordinary skill in the art to make and use the invention recited in
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`the claim without undue experimentation.
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`11.
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`I understand that, in some cases, a prior art reference can be
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`considered to disclose an element of the claim even if the reference does not
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`expressly teach it. But for a so-called “inherent” disclosure, I understand that a
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`person of ordinary skill in the art must recognize from what is expressly disclosed
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`in the reference that the missing element was necessarily present, despite the
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`reference failing to expressly disclose it.
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`10
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`UTC-2015.010
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`Case IPR2016-00962
`Patent No. 9,121,412
`I am informed that a patent claim that is not anticipated might still be
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`12.
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`unpatentable if the subject matter would have been obvious to one of ordinary skill
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`in the art in light of the prior art at the time of the invention. The claimed subject
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`matter as a whole must be considered when determining obviousness.
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`Additionally, I understand that this obviousness analysis takes into account the
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`scope and content of the prior art, the differences between the claimed subject
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`matter and the prior art, and the level of ordinary skill in the art at the time of the
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`invention. I am further informed that there must be clear reasoning for why the
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`claimed subject matter would have been obvious to one of ordinary skill in the art
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`at the time of the invention.
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`13.
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`I understand that multiple prior art references or teachings can be
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`combined to show that a patent claim would have been obvious. When taking this
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`approach, I understand that the proponent of obviousness must show that a person
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`of ordinary skill in the art would have had reason or motivation to combine the
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`references in the way the elements are recited in the claim. This reason or
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`motivation can come from different sources—like the prior art—but it cannot come
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`from the challenged patent’s own disclosure. I understand that a single prior art
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`reference, in view of the knowledge of one ordinary skill in the art at the time of
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`UTC-2015.011
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`Patent No. 9,121,412
`invention, can render a patent claim obvious if the proponent meets its requisite
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`burden of proof.
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`B.
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`The Meaning of Claim Terms
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`14. Counsel for Patent Owner has informed me that a claim subject to
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`inter partes review is to be interpreted consistent with the broadest reasonable
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`interpretation in light of the patent and its prosecution history. The words of the
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`claim are to be given their plain meaning unless that meaning would be
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`inconsistent with the patent and the prosecution history. For the claim terms
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`highlighted below, I have determined definitions consistent with the broadest
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`reasonable interpretation in light of the ’412 patent and its prosecution history.
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`15.
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`If a term was not construed by Petitioner or Patent Owner, I have
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`interpreted the claim elements of claims 1, 2, 4, 5, 7, 8, and 11 as one of ordinary
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`skill in the art at the time would have done at the time the application for the ’412
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`patent was filed. I understand that, as a general matter, a claim should not be
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`limited to a preferred embodiment, but that in certain cases, the scope of a claim
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`term may be limited by a narrowing disclosure or by positions taken, such as by
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`statements made during patent prosecution.
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`UTC-2015.012
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`Patent No. 9,121,412
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`C. Level of Ordinary Skill in the Art
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`16.
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`I understand that the technical expert retained by Petitioner in this
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`matter, Dr. Reza Abhari, has offered an opinion about the level of ordinary skill in
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`the art. Dr. Abhari has said that a person of ordinary skill in the art would include
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`“someone who has a M.S. degree in in Mechanical Engineering or Aerospace
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`Engineering as well as at least 3-5 years of experience in the field of gas turbine
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`engine design and analysis.” (GE-1003.003-004.) While I generally agree with
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`Dr. Abhari’s opinion about the level of ordinary skill in the art, it is my opinion
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`that a person of ordinary skill in the art would include someone who has a M.S.
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`degree in Mechanical Engineering or Aerospace Engineering, as well as at least 3-
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`5 years of experience in the field of gas turbine engine design and analysis, or an
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`equivalent of the same.
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`V. THE ’412 PATENT
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`17.
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` The ’412 patent identifies and claims specific combinations of gas
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`turbofan engine features that lower losses in the bypass flow passage that impact
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`propulsor (fan) efficiency. Turbofan engines include components that contribute to
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`propulsive losses in the bypass flow passage. As the ’412 patent explains,
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`“[a]lthough some basic principles behind such losses are understood, identifying
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`and changing appropriate design factors to reduce such losses for a given engine
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`UTC-2015.013
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`Patent No. 9,121,412
`architecture has proven to be a complex and elusive task.” (’412 patent at 1:27-
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`31.) The ’412 patent modifies this task by setting specific design parameters and
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`values for the fan and the bypass flow passage.
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`A. The Fan
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`18. The ’412 patent describes a “propulsor,” or fan, in the forward portion
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`of a turbofan engine. The fan provides thrust to enable flight. The fan also pushes
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`air into a core that compresses the air to combust fuel and drive turbines, which in
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`turn drive the fan. (See id. at 1:35-45.) The fan has several blades arranged
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`radially around a rotor. (See id. at Fig. 2.) The annotated figure below shows the
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`fan’s blades. (Id. at 3:2-5.) Each blade includes a “root” and a “tip.” (Id.)
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`UTC-2015.014
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`Patent No. 9,121,412
`19. A known parameter used to design fans is “solidity,” referred to as
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`“R” in the ’412 patent. (Id. at 3:24-26.) This parameter is well-known in the art,
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`and there is only one commonly accepted way of calculating solidity. (See, e.g.,
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`UTC-2018.003-.004; UTC-2019.028, .073, .246; UTC-2020.003 (defining solidity
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`at “C/s, where s is the blade spacing, or pitch, and C is the chord”).) It is defined
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`as the ratio of a fan’s chord dimension (“CD” in annotated Fig. 2 above) and its
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`circumferential pitch (“CP” in annotated Fig. 2 above). (See ’412 patent at Fig. 2;
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`id. at 3:24-26.) The chord dimension extends from the leading edge to the trailing
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`edge of a blade. (Id. at 3:5-10.) The circumferential pitch is the arc distance
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`between the tips of adjacent fan blades. (Id. at 3:5-10.)
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`20. The ’412 patent claims solidity in terms of tip solidity specifically
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`stating: “wherein each of said propulsor blades extends radially between a root and
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`a tip and in a chord direction between a leading edge and a trailing edge at the tip
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`to define a chord dimension (CD), said row of propulsor blades defining a
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`circumferential pitch (CP) with regard to said tips, wherein said row of propulsor
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`blades has a solidity value (R) defined as CD/CP . . . .” (Id. at 4:54-62.) The ’412
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`patent’s specification also explains that “[a] chord dimension (CD) is a length that
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`extends between the leading edge 82 and the trailing edge 84 at the tip of each
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`propulsor blade 74. The row 72 of propulsor blades 74 also defines a
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`15
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`UTC-2015.015
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`circumferential pitch (CP) that is equivalent to the arc distance between the tips 80
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`of neighboring propulsor blades 74.” (Id. at 3:5-10 (emphases added).)
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`21. The ’412 patent relates the number of blades in the fan (“N”) with the
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`fan’s solidity (“R”) to define specific ratios of N/R. (See id. at 3:38-4:21.) This, in
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`combination with other claimed parameter values, can “enhance the propulsive
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`efficiency of the disclosed engine.” (Id. at 4:9-12; see also id. at 3:38-4:21.)
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`B.
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`The Bypass Flow Passage
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`22. When the fan generates pressure and drives air through the engine, the
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`air proceeds through two main paths. The first is a core flow path, where fuel is
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`combusted to ultimately drive the fan and to generate a relatively small portion of
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`the engine’s thrust. (See, e.g., id. at Fig. 1; id. at 3:32-36.) The second is a bypass
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`flow passage, where the fan generates most of the engine’s thrust by forcing air
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`through a bypass duct and out a nozzle at the rear of the bypass duct. (See, e.g., id.
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`at Fig. 1; id. at 3:32-36.) The annotated figure below shows the first path (“C” in
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`orange) and the second path (“B” in blue), after the air passes the fan. (See id. at
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`Fig. 1.)
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`16
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`UTC-2015.016
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`23. Structures in the bypass flow passage can impact the pressure and
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`drive pressure changes, as a result of the air’s interactions with such structures.
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`Structures in the bypass flow downstream of the fan can include: a fan hub holding
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`the blades of the fan; fan exit guide vanes; a core flowpath inlet; an exhaust duct
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`and nozzle; pylon mounting structures (intended to provide structural support); air
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`bleed or exhaust ports; heat exchangers; noise suppression structures; measurement
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`ports and sensors; and discontinuities between portions of the duct and its
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`components that cause air leakage in the passage, among other things.
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`24. For example, heat exchangers in the bypass flow passage can cause
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`pressure losses in the air passing through the duct, as it would partially obstruct the
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`airflow. Additionally, heat exchangers add heat to the air in the bypass flow
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`17
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`UTC-2015.017
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`Patent No. 9,121,412
`passage. One study suggests that the addition of heat exchangers in turbofan
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`engines can amount to 5.3% in losses. (See UTC-2023.003.)
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`25. As another example, the use of a constricting bypass flow path exit
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`nozzle, like the one used in Davies, causes a rapid reduction in the bypass flow
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`passage’s cross-sectional area. Persons of ordinary skill typically expect this to
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`result in substantial changes in pressure, between the beginning and the end of the
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`bypass flow passage. In this regard, I understand that during his deposition, Dr.
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`Abhari identified points just before and after Davies’s constricting exit nozzle as
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`the measurement locations for determining the amount that the exit nozzle reduces
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`flow area.
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`26.
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`It is my opinion that Dr. Abhari identifies incorrectly the change in
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`cross-sectional flow area caused by the bypass exit nozzle. Determining this
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`parameter requires determining the mean bypass area, which is calculated based on
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`several diameters or radii from the centerline (“Ri”) and duct heights (“Hi”), and
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`then comparing the mean bypass area to the exit nozzle area, which also is based
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`on exit radius and height (“Re” and “He”), as shown below in annotated Figure 1 of
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`18
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`UTC-2015.018
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`Case IPR2016-00962
`Patent No. 9,121,412
`Davies, GE-1005.019 (annotations by Dr. Abhari during his deposition1).
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`Dr. Abhari does not mention or attempt to apply this standard, commonly accepted
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`exercise.
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`27. Pressure changes across the bypass flow path can impact the overall
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`thrust of the engine. The consequences of these pressure changes on the engine’s
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`1 Dr. Abhari’s annotations are in orange, pink, purple, and blue. My notations are
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`in green. As I explain later in my declaration, I also disagree with Dr. Abhari’s
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`identification of the claimed bypass flow passage’s measurement location for the
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`inlet, which Dr. Abhari annotated in orange.
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`19
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`UTC-2015.019
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`thrust are not negligible. (See UTC-2007.006, Fig. 10.) Thus, aircraft engine
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`designers carefully scrutinize and account for all changes in pressure across a
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`turbofan engine’s bypass flow passage.
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`28.
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`In the ’412 patent, a bypass flow passage “B” is expressly described
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`as extending from inlet 60 to outlet 62. The ’412 patent also defines a bypass flow
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`passage pressure ratio (“BFPPR”) between these two points. It accounts for all
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`pressure changes (whether intended or not) within the bypass flow passage. The
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`pressure changes include those between the inlet and the fan, pressure increases
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`created by the fan, and pressure changes created by the remaining structures in the
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`bypass duct’s air flow passage. (See ’412 patent at 2:49-55.)
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`29. The claimed ranges of BFPPR in the ’412 patent are critical to the
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`engine’s design and operation. The BFPPR allows for the engine’s design and
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`optimization process to account for a more complete picture of pressure changes in
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`the bypass duct. It provides a “design pressure ratio” that enables optimization of
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`many components in the engine. (See id. at 2:55-65; id. at 3:28-32.)
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`30. The parameter can be used, for example, to optimize a variable-area
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`exhaust nozzle, if used, and thereby enhance engine thrust performance and fuel
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`efficiency. (See id. at 2:55-65.)
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`20
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`UTC-2015.020
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`31. As another example, the parameter can be used to design the fan.
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`This will “enhance propulsive efficiency by reducing performance debits of the
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`propulsor [i.e., the fan].” (Id. at 3:11-15.) It is known that the operating point of
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`low fan-pressure ratio fans, such as those used in high bypass turbofan engines, are
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`sensitive to duct pressure changes and losses. Their performance therefore
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`depends on the pressure changes caused by structures in the bypass duct. This
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`requires careful design of all structures in the duct. And the claimed BFPPR
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`provides a more complete picture of the required pressure rise for producing thrust,
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`that incorporates not only the pressure rise generated by the fan, but also all
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`pressure losses generated by elements in the bypass duct, enabling careful design
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`of the bypass duct.
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`32. By balancing these inter-dependencies, e.g., between fan performance
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`and structures in the bypass flow passage, engine components can be designed to
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`enhance performance and efficiency. In the ’412 patent, this is in large part
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`accomplished by defining a pressure ratio between the beginning and the end of the
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`bypass flow passage.
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`33.
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`It is known that selection of the BFPPR also is critical because, in
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`some cases, engine performance can vary significantly with selection of this
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`parameter. That is, little differences in BFPPR could mean significant differences
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`21
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`UTC-2015.021
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`in overall engine performance (including fuel consumption). As I stated above, the
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`BFPPR includes the fan pressure ratio (“FPR”) and other pressure changes within
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`the bypass flow passage. Even if one were to consider only the FPR, as Dr. Abhari
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`does, there are similar engine performance and sensitivity issues.
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`34. For example, the annotated figure below shows thrust-specific fuel
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`consumption2 (TSFC) curves, as a function of FPR, πf. (See UTC-2017.004.)
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`Each curve represents example engine designs with a given bypass ratio, α. The
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`solid curves represent example engine designs with losses throughout some of the
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`main engine components (e.g., compressors, turbines, and combustor) accounted
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`for.
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`35. As can be seen in the example below, for an engine design with a
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`bypass ratio of α = 3, a FPR difference of 0.4 (from πf = 4.0 to πf = 4.4) results in
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`only a small difference of TSFC. By contrast, for an engine design with a bypass
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`ratio of α = 5, the same FPR difference of 0.4 (from πf = 3.0 to πf = 3.4) results in a
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`much greater difference in TSFC.
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`
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`2 Thrust-specific fuel consumption is the rate of fuel use by the engine per unit of
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`thrust produced. It is an indicator of performance and efficiency.
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`22
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`UTC-2015.022
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`36. As this example shows, if one considers TSFC curves for even higher
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`bypass ratio engine designs, the design’s TSFC sensitivity (e.g., engine
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`performance) increases for the same amount of change in FPR. And as I stated
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`above, the FPR is one part of the BFPPR, which also includes other pressure
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`changes within the bypass flow passage. Accordingly, under either Dr. Abhari’s
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`consideration of only the FPR or the ’412 patent’s use of the broader BFPPR, the
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`same observation regarding higher bypass ratios and an engine design’s TSFC
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`23
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`UTC-2015.023
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`sensitivity to pressure ratio differences is true: with engine designs of higher
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`bypass ratio, as compared to those with a lower bypass ratio, the design’s TSFC
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`sensitivity to pressure ratio differences also increases.
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`C. The Claimed Bypass Flow Passage Pressure Ratios
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`37.
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`I have been asked to provide a construction of the claimed term,
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`“pressure ratio . . . with regard to an inlet pressure and an outlet pressure of said
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`bypass flow passage.” I understand that Petitioner has stated the term means that
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`“the bypass pressure ratio of a turbofan engine having a conventional bypass duct
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`is substantially equivalent to the fan pressure ratio.” (Petition at 16-17.) It is my
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`opinion that a person of ordinary skill would not agree that this is the meaning of
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`the claimed BFPPR. It is not consistent with the ’412 patent and known
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`characteristics of engine designs. It is my opinion that a person of ordinary skill
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`would understand the claimed BFPPR in the ’412 patent to mean “the ratio of the
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`pressure at the inlet of the bypass flow passage to the pressure at the outlet of the
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`bypass flow passage.”
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`38. Apart from explaining where the BFPPR is to be measured, at the
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`beginning and the end of the bypass flow passage, the ’412 patent also claims
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`BFPPRs that are to be measured in the same locations. It also claims specific
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`ranges of values for the claimed BFPPRs. Claim 1, for example, recites a
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`24
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`UTC-2015.024
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`“pressure ratio that is between 1.1 and 1.35 with regard to an inlet pressure and an
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`outlet pressure of said bypass flow passage.” (’412 patent at 4:50-53.) Claims 2
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`and 4 also claim pressure ratios that range from 1.2 to 1.3, and 1.1 to 1.2. (See id.
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`at 4:63-64; id. at 5:3-4.)
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`39. A person of ordinary skill in the art would understand the claims as
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`referring only to the pressure ratio of the entire bypass flow passage. One would
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`not understand the claims as referring to any other pressure change in the duct,
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`such as a FPR, which is intermediate to the broader bypass flow passage pressure.
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`Indeed, using a FPR as a proxy for the claimed BFPPR goes against the ’412
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`patent’s disclosures and purpose. The ’412 patent does not separately refer to or
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`describe a “fan pressure ratio.” And it does not include any disclosure in which the
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`described optimization process considers only a “fan pressure ratio” or an
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`approximation of the claimed pressure ratio. In this sense, the ’412 patent also
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`does not provide any teaching on the threshold for what would be a “substantially
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`equivalent” pressure ratio. And if the inventors had intended the FPR to be
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`synonymous with the BFPPR, one would have expected the ’412 patent to refer to
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`FPR alone. But the ’412 patent does not. Accordingly, a person of ordinary skill
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`would not believe the claimed BFPPR is “substantially equivalent” to a FPR.
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`25
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`UTC-2015.025
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`40. Like almost any other engine, the ’412 patent describes and shows
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`structures between the beginning (60) and the end (62) of the bypass flow passage.
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`For example, the ’412 patent describes a variable area fan outlet nozzle. (’412
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`patent at 2:56-65.) This structure would cause the BFPPR to differ from the FPR.
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`Other sources of changes to the BFPPR include the inlet and its associated
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`geometry, duct walls that create variable cross-sectional flow passages, and an
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`outlet, which can be seen below in annotated Fig. 1 of the ’412 patent. (Id.)
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`41.
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` A person of ordinary skill also would expect other engine designs,
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`besides those described in the ’412 patent, to have structures that cause the BFPPR
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`to differ from the FPR. Davies’s (GE-1005) bypass duct, for example, includes
`26
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`UTC-2015.026
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`Patent No. 9,121,412
`several structures that would cause pressure changes. Such structures in Davies
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`include:
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`• Elongated intake and outlet cowls, to limit engine noise.
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`• Unconventional aft ducting between the fan and the outlet, to supply
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`additional air during reverse thrust generated by the variable pitch fan.
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`• A bleed duct valve fitted to the intermediate compressor outlet, to cope with
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`variations in loading caused by the changing pitch of the fan.
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`• An intermediate casing between the fan and the intermediate compressor, to
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`reposition the core behind the outlet
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