The faculty here at Virginia Tech have been involved in research, development and promotion of CLT for more than a decade. Our work has helped to get southern pine included in the ANSI/APA PRG 320 Standard for CLT panels, started the investigation of hardwood use in CLT manufacture, and has assisted with potential development of CLT manufacturing capability in the southeast region of the United States.
This web page is created and maintained by the Department of Sustainable Biomaterials at Virginia Tech with the goal to promote our effort and inform stakeholders about the advancements of using hardwood and softwood lumber for the manufacturing of Cross-Laminated Timber (CLT) panels. Any comments please email Dr. Henry Quesada at email@example.com.
ANSI/APA PRG 320-2019 Standard for Performance-rated Cross-laminated timber
The last version of the ANSI/APA PRG-320 standard was released by APA in January 2020. This version can be download here.
Dr. Henry Quesada is a voting member of this committee and Dr. Daniel Hindman is also part of the committee as an observer. Having a vote in this Committee is critical for the advancement of CLT technology. The committee decides on the raw materials, panel configurations, process, and quality assurance of CLT panels.
Cross-laminated timber (CLT) is defined by the ANSI/APA PRG-320 standard as “a prefabricated engineered wood product made of at least three orthogonal layers of graded sawn lumber or structural composite lumber (SCL) that are laminated by gluing with structural adhesives.”
Current CLT manufacturers in the US (as 2021)
- DR Johnson
- Location: Riddle, OR
- Species use: Douglas-fir
- Annual production capacity: Approximately 5,000 cubic meters
- Main products: structural CLT panels and glue lams
- SmartLam, LLC
- Locations: Kalispell, MT and Dothan, AL
- Species use: Spruce-Pine-Fir (SPF) in MT and Southern-yellow-pine (SYP) in Alabama
- Annual production capacity: Approximately 170,000 cubic meters
- Main products: non-structural CLT panels (road matts) and structural CLT panels
- Freres Lumber Co., Inc.
- Locations: Lyons, OR
- Species use: Douglas-fir
- Annual production capacity: Unknown
- Main products: Mass plywood, structural CLT panels, and Structural Composite Lumber (SCL).
- Location: Phoenix, IL
- Species use: Southern-yellow-pine (SYP)
- Annual production capacity: Approximately 300,000 cubic meters
- Main products: non-structural CLT panels (access road mats)
- Spartan Mat, LLC
- Location: Portland, OR
- Species use: Southern Yellow Pine
- Capacity: Unknown
- Main products: non-structural CLT panels (access road mats)
- Location: Conway, AR
- Species use: Southern Yellow Pine and Spruce-Pine-Fir
- Annual production: Unknown
- Main Products: Non-structural CLT panels, structural CLT panels, and Gluelams
- Mercer Mass Timber
- Location: Spokane, WA
- Species use: SPF
- Annual production: 13 million ft2 of 5-ply panels or 140,000 m3 (5 days/week)
- Main products: structural CLT panels
- Vaagen Timbers, LLC
- Location: Colville, WA
- Species use: Unknown
- Annual production capacity: 117,000 cubic meters
- Main products: Structural CLT panels and glue lams
- Texas CLT
- Location: Magnolia, AR
- Species use: Southern Yellow Pine
- Annual production capacity: 5.4 million ft2 (8h/day, 5 days/week)
- Main products: structural and non-structural CLT panels (access road mats)
- Viking Mat Company
- Location: Eden Prairie, MN
- Species use: Unknown
- Production capacity: unknown
- Main products: Non-structural CLT panels (access road mats)
- Yak Mat
- Location: Columbia, MS
- Species use: Southern Yellow Pine
- Production capacity: unknown
- Main products: Non-structural CLT panels (access road mats)
CLT research projects at Virginia Tech
- Softwood Export Council. Lumber supply issues impacting cross-laminated timber (CLT) mills in the US. Henry Quesada (PI), Sailesh Adhikari (Co-PI),and Robert Smith (Co-PI). $10,000. Period Fall 2021
- Abstract: For US CLT manufactures procurement of lumber is critical to meet customer requirements. Some CLT manufacturers have reported problems with the supply of lumber due to several factors. This project aims to investigate how supply chain issues in the US are impacting the CLT mass timber industry.
- Softwood Export Council. Mass timber fact sheets for the Latin American market. Henry Quesada (PI), Sailesh Adhikari (Co-PI),and Robert Smith (Co-PI). $6,000. Period Fall 2021.
- Description: The purpose of these fact sheets will be to introduce key concepts related to mass timber so stakeholders in this region of the World might have a better understanding of the advantages and disadvantages of this construction system.
- USDA Forest Service. Expanding Markets for timber industrial mats manufactured from hardwood species and cross-laminated timber (CLT). Tammy Franca (PI) and Dan Seale (Co-PI) with Mississippi State University (PI), Henry Quesada (Co-PI). $206,125. Period 2021-2023.
- Abstract: The goals of this project are to (1) make CLT timber matts using hardwood species; and (2) test the natural durability performance of the new product. Most of the research on CLT is related to the mechanical property behavior of the panels. Softwoods are the raw material most used in the manufacturing process of CLT panels and the main application of these panels are for structural purposes. However, not much attention has given to biodegradation properties of this product and the potential of using different species other than softwood to produce CLT panels. In conjunction with Sterling Lumber and Superior Mat Company, this project aims to increase the consumption of low value hardwood and to create a new market for CLT panels. The market for CLT mats is growing faster than for architectural use. The consumption of CLT for buildings in North America is around 45,000 m³, while industrial mats consume 118,000m³. The project will determine the susceptibility of different industrial mats made with yellow poplar (YP) and oak (OK), bolted oak mat and compare with standard mats built with southern yellow pine (SYP). The knowledge obtained through this project will be provided to stakeholders in the wood industrial mats, hardwood lumber producers, wood products sales and marketing specialists. Outcomes anticipated from the results of this project is to improve and expand the use of hardwood species and create a new market for CLT, focusing on non-structural uses. In addition, this project will help to sustain and create new jobs in the hardwood industry.
- Architecture and Construction Alliance (AMM5VDZ6). Mass Timber Use in Building Construction Webinar Series. Daniel Hindman (PI), Brian Bond (Co-PI), Thomas Mill (CO-PI), and Henry Quesada (Co-PI). $4564. Period 2021-2022.
- Abstract: Since mass timber is a relatively new product, there is little curricular material available for use in the architecture and building construction areas. At Virginia Tech, members of the Sustainable Biomaterials department have been researching mass timber and cross-laminated timber materials since 2012 and have gained a wealth of knowledge related to mass timber products and construction methods and made numerous connections and partnerships with mass timber manufactures and builders. The webinar would provide an excellent way to and influence awareness and provide our experience and knowledge for current and future construction professionals.
- USDA Forest Service (20-DG-11083150-010). Increasing hardwood utilization in the cross-laminated timber market. Henry Quesada (PI) and Brian Bond (Co-PI). $268,567. Period: 2020-2022.
- Abstract: The goal of this project is to create a new market for hardwood use in the manufacturing of cross-laminated timber (CLT) panels. Currently, the CLT code PRG-320, only accepts selected softwood species for the manufacturing of CLT panels and all work conducted on increasing hardwood use in CLT’s has focused on producing and using them as structural components. In this project, we will focus on creating an opportunity to increase hardwood use in CLT by adding hardwood to the outer layers of CLT’s, primarily for its visual appearance. Many CLT panels are used as wall and flooring components and other materials are added for decorative walls and flooring. By using hardwood on the outer layers of softwood CLT’s, we can increase hardwood use. Hardwood veneer and lumber will be added to the outer layers of CLT panel cores made from southern yellow pine in compliance with PRG-320. This project will partner with Danzer Veneer America, Allegheny Wood Products (AWP), and Texas CLT to manufacture and evaluate the performance and potential market acceptance of CLT panels made with hardwood veneer and lumber on the outer layers. We will evaluate for delamination of the hardwood veneer and lumber from the softwood core and determine what influence the hardwood layers have on the strength properties of CLT. We will conduct a market perception test of the hardwood veneer laminated CLT panels among architects and structural designers in the U.S. We believe that the results of this work could increase the market for hardwood veneers and lumber by 10% of the current consumption.
- USDA Forest Service (19-DG-11083150-021) . Multi-State Effort to Overcome Barriers to Low-value Hardwood Lumber for CLT Manufacture. Henry Quesada (PI), Brian Bond, and Eva Haviarova (subcontract with Purdue University). $249,765. Period: 2019-2022.
- Abstract: This project is a multistate industry-university collaboration between SmartLam, the Northeastern Lumber Manufacturers Association (NELMA), the American Plywood Association (APA), IKD Architectures, Virginia Tech, and Purdue University to advance the utilization of hardwood lumber for the fabrication of Cross-Laminated Timber (CLT). This new proposal builds upon a previous Wood Innovation project. The collaboration among the organizations proposes to: 1) apply the shear analogy method to hardwood species listed in the National Design Standards (NDS) supplement to assure these species are feasible for the construction of structural CLT panels, 2) create a custom grade CLT layup made of yellow poplar (Liriodendron tulipifera) lumber and get its approval by the Engineered Wood Association (APA), 3) train the hardwood industry in the Midwest and in the Southeast on the application of hardwood structural lumber grading rules, and 4) perform mechanical testing on the hardwood CLT panels used in the Conversation Plinth project by IKD Architectures in Columbus, IN. In 2012 Virginia Tech conducted the first experimental tests on hardwood CLT panels. Results indicated that bonding, strength, and stiffness of yellow poplar CLT panels matched or were superior to some of the softwood CLT layups in the APA standard. Similar results were also obtained by independent testing conducted by the American Hardwood Export Council (AHEC) in 2018. However, further investigation by Virginia Tech found that the main limitations for the use of yellow poplar and other low value hardwood species in CTL panels are 1) lack of experimental data on other hardwood species used in CLT panels, 2) lack of supply of structurally graded hardwood lumber, and 3) acceptance and validation of hardwood CLT panels by the APA standard. Overcoming these limitations is critical for the hardwood lumber industry in order to gain access to the CLT market. Currently, the annual production of CLT panels in the US is about 35,000 m3 but it is expected that in 10 years production will be close to 2 million m3 per year. The outcomes of this project are to increase the utilization of low-value hardwood species from national and private forests and to increase economic development in rural areas in the hardwood regions of the US.
- USDA Forest Service (16-DG-11083150-053). Developing of CLT Markets for Hardwood Lumber Producers to Promote Economic and Environmental Health of Forest and Communities. Henry Quesada (PI) and Brian Bond. $208,977. Period: 2016-2020.
- Abstract: The potential for using low value hardwood timber in new construction materials such as cross-laminated timber (CLT) represents an incredible opportunity for hardwood market expansion and the utilization of low value timber from our nation’s forests. Research conducted at Virginia Tech has demonstrated the feasibility of using low value timber for CLT panels, creating a new market opportunity for the traditional hardwood lumber industry (Beagley et al. 2014). This new market would also allow for the use of the large percentage of timber in national forests that is considered of low value and currently is not being considered for harvesting because the lack of appropriate markets, leading to increased fire danger. One of the major barriers for successful hardwood CLT implementation is the efficient manufacturing of hardwood lumber specifically produced for CLT production. Currently, hardwood sawmills are designed for appearance grade lumber production and not for the specific strucutural grade purposes required for CLT’s. Little is known about the barriers that exist or the incentives needed for hardwood mills to enter this market. The goal of this project is to provide hardwood lumber producers with information to assist them in entering the CLT market with material produced from low value hardwoods. The goal will be accomplished by first determining manufacturing capabilities of current hardwood producers for the production of raw materials used in CLTs. Current capabilities and limitations of traditional hardwood lumber producers will be determined through a survey of industries in in the Appalachian region. Secondly, with the support of the local hardwood industry on specific procurement, manufacturing, costing and quality control procedures (such as visual strength grading), we will develop an analytical tool in MS Excel to assist manufactures with making decisions for the successful production of raw materials for CLTs. Lastly, we will work with industry and industry associations through Virginia Cooperative Extension, to provide interactive workshops where not only will the information gathered in the project be presented, but the participants will be walked through the process of using the analytical tool, so they can develop their own financial and manufacturing scenarios. The potential development of new hardwood markets for low value timber, such as the production of CLT raw materials or parts, could bring significant health and sustainability benefits for both public and private forests Virginia and in other states in the Eastern region of the U.S.
- Softwood Export Council (SEC). Travel Grants. $20,000. Bob Smith (PI), and Henry Quesada. Period: 2018-current.
- Use of Southern Yellow Pine for the Manufacture of Cross-Laminated Timber Panels for Commercial Construction. CIT, Commonwealth Research Commercialization Fund (CRCF), Commonwealth of Virginia. Daniel Hindman (PI), David Kenealy (co-PI). $250,000 2012-2014.
- Abstract: This project focused on testing a technologically-innovative construction material, Cross-Laminated Timber panels (CLTs) made of Southern Yellow Pine (SYP), in order to provide data required for commercialization in Virginia. CLT panels are an engineered structural wood product used for decades in Europe, and more recently in Canada, but have only very recently begun to be considered for commercial production in the U.S. One of the chief challenges for commercialization of SYP CLTs has been the lack of testing data needed to support inclusion of the product in U.S. building codes. In this project, a collaborative team of researchers prototyped and performance tested SYP CLT panels. The project was led by Mr. David Kenealy, Director of the Research & Development Center for Advanced Manufacturing (R&D CAMEE) at the Southern Virginia Higher Education Center (SVHED) and Dr. Daniel Hindman, Department of Sustainable Biomaterials, College of Natural Resources and Environment, Virginia Tech. The research and testing conducted in this project found that the strength, stiffness and acoustic properties of CLT panels made from SYP met or exceeded current code standards for CLT, and results suggest that using SYP will be advantageous for future production of CLTs in the US. This project has yielded the data necessary to have CLTs made from SYP included in U.S. commercial building codes and this move the product toward commercialization.
- Advancing Commercialization of Cross-Laminated Timbers Made From Southern Yellow Pine Through Materials and Process Testing. CIT, Commonwealth Research Commercialization Fund (CRCF), Commonwealth of Virginia. David Kenealy – PI, Daniel Hindman co-PI $157,448 2014-2015
- Abstract: CLT panels are an engineered structural wood product used for decades in Europe for residential and commercial construction; builders in Canada have recently begun to use CLT panels as well. CLT panels are gaining interest in the United States because they represent a cost-effective, energy-efficient alternative to traditional building materials. In 2012, the American National Standards Institute (ANSI) approved a standard for performance rating of CLT panels in the United States. A previous CRCF-funded study by Southern Virginia Higher Education Center/Virginia Tech research team found the material properties of CLTs fabricated from Southern Yellow Pine, a major commercial timber species in Virginia, were acceptable within the ANSI/APA PRG 320 standard. While ANSI/APA PRG-320 provides performance standard for CLTs, many of the manufacturing process variables related to CLTs have not been explored. This project investigated the impact of manufacturing process variables on CLT performance. The team tested panels fabricated under a range of values for each of the three variables being studied: addition of moisture adhesive joints, lamination pressure (measured in pounds per square inch or psi), and press time. Understanding these variables is essential for efficient and reliable future production of SYP CLT materials in Virginia. Partners for this project included: R&D CAMEE, a division of the Southern Virginia Higher Education, serving as prime applicant and Virginia Tech’s Department of Sustainable Biomaterials.
- USDA NIFA (2012-34638-20333). Development of Hardwood Cross-Laminated Timbers. Dan Hindman (PI), Joe Loferski, Earl Kline, Brian Bond and Henry Quesada. Subcontracts: DeVallance, D. (West Virginia University), and Young, T (University of Tennessee). $300,616. Period: 2012-2015.
- Abstract: Sustainable solutions to building construction can help improve material utilization efficiency while providing economic development. The purpose of this research project is to develop new markets for low-grade hardwoods by demonstrating the use of hardwood CLT manufacture. The project addresses two of the four specified areas of the Integrated Forest Products Research Grant (Value Improvement of Low Quality Hardwoods, and Developing Structural Composites, Specifically CLTs). Specific aims address the production of hardwood CLTs including: adhesive bonding needs, laboratory-scale panel manufacture, mechanical property evaluation, mechanical property modeling, and statistical process control needs for full-scale hardwood CLT manufacturing facilities. The results of these specific aims will be integrated into educational programs targeted at undergraduate and graduate students, forest products industry professionals, designers and engineers, and the general public. The Wood Products Community of Practice (CoP) will be used to disseminate information related to hardwood CLTs. A unique aspect of this proposal is the combination of three land-grant research institutions with the Southern Virginia Higher Education Center. The Higher Education Center will be the site of workshops with hands-on training in manufacturing hardwood CLT panels. Undergraduate and graduate programs will also help train future forest products industry professionals about CLTs throughout the project, as well as curriculum development by all participating institutions. Results from this project will help expand the knowledge of wood species for CLT production giving future CLT manufacturers in the United States more flexibility in material choices to reduce costs or to produce CLT panels from regional materials.
- Adhikari, S., Quesada, H. Bond, B., and Hammett, T. 2021. Current Status of Hardwood Sawmills to Produce Structural Grade Hardwood Lumber. Mass Timber Construction Journal. 4(1):10-18.
- Gonzalez, J., Quesada, H., Adhikari, S., Bond, S. and Grushecky, S. 2020. Design of a Total Revenue Forecasting Tool to Estimate the Economic Output of Hardwood Logs. Forest Products Journal. Accepted in August.
- Adhikari, S., Quesada, H. Bond, B. and Hammett, T. 2020. Potential of Hardwood Lumber in Cross Laminated Timber in North America: A CLT Manufacturer’s Perspective. Mass Timber Construction Journal. 3(1):1-9.
- Quesada, H., Smith, R. Berger, G., and Loferski, J. 2020. Visual Inspection of Cross-laminated Timber Buildings in Austria. BioProducts Business 5(5):51-62. https://doi.org/10.22382/bpb-2020-005
- Hindman, D. P., M. V. Golden. 2020. Acoustical Properties of Southern Pine Cross Laminated Timber Panels. Journal of Architectural Engineering. Accepted for publication.
- Quesada H.J.; Bond B; Adhikari S., Grushecky S. 2019. Analysis of Hardwood Lumber Grade Yields Using Monte Carlo Simulation. BioResources 14(1):2029-2050.
- Bouldin, J. C., Hindman, D. 2018. Bending and Shear Stiffness of Cross-Laminated Timber Using a Variable Span Bending Test. Journal of Testing and Evaluation. 47(4):2464-2475.
- Quesada, H. J., Smith, R., and Berger, G. 2018. Drivers and Barriers of Cross-laminated Timber (CLT) Production and Commercialization: A Case Study in the Western Europe’s CLT industry. BioProducts Business. 3(3): 29-38.
- Sharifnia, H., Hindman, D. P. 2017. Effect of Manufacturing Parameters on Mechanical Properties of Southern Yellow Pine Cross Laminated Timbers. Construction and Building Materials. 156:314-320.
- Richardson*,B.L., Hindman, D. 2016. Lateral resistance of cross-laminated timber panel-to-panel connections. World Conference on Timber Engineering. August 22-25, 2016. Vienna, Austria.
- Hindman, D. P, J. C. Bouldin. 2015. Mechanical properties of southern pine cross-laminated timber. Journal of Materials in Civil Engineering. 27(9), 04014251 .
- Hindman, D. and Bouldin, J. 2014. Development of Southern Pine Cross-Laminated Timber for Building Code Acceptance. World Conference on Timber Engineering. Quebec City, Canada. August 10-14.
Organized workshops and seminars
- Structural grading for hardwood lumber. 2021. Quesada, H., Adhikari, S., Inman, T. Sibert, L. October 13. Roanoke, WV.
- Opportunities for Hardwood Lumber in Mass Timber. 2021. Quesada, H. IUFRO World Day. Online seminar. September 29.
- Use of Low value Hardwoods for CLT and other Value-added Products in Central Hardwood Region: Part I. 2018. Speakers: Quesada, H. (co-organizer), Haviarova, E. (co-organizer). April 4. West Lafayette, IN.
- Cross Laminated Timber (CLT): What Is It & Why It Should Be On Your Radar. Virginia Forest Products Association (VFPA) Annual Convention. Speakers: Quesada, H. (co-organizer), Becker, C., Chung, T., and Judd, C. September 9. Norfolk, VA.
- Using Cross Laminated Timber for Building Construction. 2017. Workshop. Speakers: Quesada, H. (organizer), Camacho, D. (co-organizer), Hindman, D., Chung, T. and Judd, C. Funded by the VP of Research of Costa Rica Tech and the Department of Sustainable Biomaterials at VT. April 20. San Jose, Costa Rica.
- Mitchell O. Carr Symposium on Innovative Use of Wood. 2016. Organizing committee: Bond, B. (Chair), Quesada, H., Hindman, D. Loferski, J. Parrott, K. Ishida, A., and Goldsmith, D. Sponsor by Mitch Carr with a $45,000 donation. March 18-21. Blacksburg, VA.
Conference and Industry meeting presentations
- Quesada, H. 2021. New Markets for Hardwoods. National Hardwood Lumber Association Convention. September 21-24. West Palm Beach, FL. To see the presentation follow this link.
- Hindman, D. 2020. Hardwood Lumber Used for Cross-Laminated Timber. Presented at the 55th Kentucky Forest Industries Association Annual Meeting, August 27.
- Quesada, H. 2020. Opportunity for the Hardwood Industry into the CLT market. NextGen Leader Council. Hardwood Manufacturers Association (HMA). Online presentation.
- Quesada, H.J., Adhikari, S, Bond, B. 2019. Hardwood Cross-Laminated Timber: Readiness of US Hardwood Lumber Manufacturers. Paper presentation in session Timber Engineering and Mass Timber. SWST International Convention. October 21-25, 2019. Fish Camp, California.
- Quesada, H. 2018. Is the CLT Market an Opportunity for the US Hardwood Industry? National Hardwood Lumber Association (NHLA) Convention. Toronto, Canada.
- Quesada, H.J., and Adhikari, S. 2018. Application of Montecarlo Simulation to Hardwood Lumber Yields. Paper presentation in session Business and Marketing. SWST joint International Convention. November 5-9, 2018. Nagoya, Japan.
- Adhikari, S. Quesada, H.J., and Bond, B. 2018. Value Analysis of Appearance-Grading vs Combined Appearance and Stress-Grading for Hardwood Logs. Poster presented in Poster Session 1. SWST joint International Convention. November 5-9, 2018. Nagoya, Japan.
- Smith, R. Quesada, H. Berger, G. 2018. Drivers and Barriers of Cross-laminated timber production and commercialization. Mass Timber Conference. Poster.
- Hindman, D., Boulding, J., Loferski, J., Bond, B, and Quesada-Pineda, H. 2016. Mechanical, Acoustic, and Fire Properties of Southern Pine Cross-Laminated Timber. International Woodworking Fair. August. Atlanta, GA.
Technical notes and working papers
- Mohamadzadeh, M., and Hindman, D. 2015. Mechanical Performance of Yellow-Poplar Cross Laminated Timber. The Charles E. Via, Jr. Department of Civil and Environmental Engineering . Report No. CE/VPI-ST-15-13
- Barriers to using hardwood lumber in structural CLT panels. See article here.
- Hindman, D. P. 2015. Incorporating Cross-Laminated Timber into Post-Frame Buildings. Frame Building News. November 2015. Available here: http://www.constructionmagnet.com/wp-content/uploads/1115-RT.pdf
Press releases and newsletters
- Fleming, D. 2021. From green wood to a green world: How Extension specialists are impacting America’s hardwood industry. October 27. Virginia Tech Daily News. Available at https://vtx.vt.edu/articles/2021/10/cnre-wood-extension-impact.html
- NHLA News. 2019. New Grant to Continue to Pursue Hardwood Lumber for CLT.
- School of Architecture + Design. 2018. AIA Blue Ridge Awards Kay Edge and Edward Becker’s Design-Build.
- Virginia Loggers Association Newsletter. 2018. Is the Cross-laminated timber (CLT) market an option for the hardwood industry? August.
- The Roanoke Times. 2019. Train observation tower opens at Radford’s Glencoe Museum
- Appalachian Hardwood Manufacturers, Inc.
- National Hardwood Lumber Association
- Hardwood Manufacturers Association
- American Hardwood Export Council
- US Forest Service Wood Innovations Grant
- Softwood Export Council
- Henry Quesada, Professor and Extension Specialist. Department of Sustainable Biomaterials
- Brian Bond, Professor and Extension Specialist. Department of Sustainable Biomaterials
- Dan Hindman, Associate Professor. Department of Sustainable Biomaterials
- Sailesh Adhikari, Research Associate. Department of Sustainable Biomaterials.
- Edward Becker, Associate Professor. School of Architecture.
- Kay Edge, Associate Professor. School of Architecture.
- Bob Smith, Professor. Department of Sustainable Biomaterials
- Joe Loferski, Professor. Department of Sustainable Biomaterials