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Author: Michael Altgen Publisher: Cuvillier Verlag ISBN: 3736984219 Category : Science Languages : en Pages : 166
Book Description
Various thermal wood modification technologies have been developed in Europe during the past decades that differ notably in the process conditions applied. However, the changes in wood properties by thermal modification, the underlying modes of action and their link to the process conditions are still not fully understood. This thesis investigates the influence of different process conditions in open and closed reactor systems on the resulting properties of thermally modified wood. In closed reactor systems, elevated water vapor pressure accelerates the thermal degradation of wood polymers and results in high mass loss levels even at mild treatment temperatures. However, in addition to the loss in wood mass, a strong influence of drying and softening of wood at elevated temperatures as well as an increased cell wall matrix stiffness by modification of the lignin carbohydrate complex under dry heat conditions influences the wood properties, i.e. water sorption. For wood thermally modified in open reactor systems at different peak temperatures and durations, the surface performance is investigated with regard to the susceptibility to surface cracking, photodegradation and coatability. The results provide explanations why the performance of thermally modified wood in exterior applications does not always meet the expectations derived from its enhanced resistance against decay fungi.
Author: Michael Altgen Publisher: Cuvillier Verlag ISBN: 3736984219 Category : Science Languages : en Pages : 166
Book Description
Various thermal wood modification technologies have been developed in Europe during the past decades that differ notably in the process conditions applied. However, the changes in wood properties by thermal modification, the underlying modes of action and their link to the process conditions are still not fully understood. This thesis investigates the influence of different process conditions in open and closed reactor systems on the resulting properties of thermally modified wood. In closed reactor systems, elevated water vapor pressure accelerates the thermal degradation of wood polymers and results in high mass loss levels even at mild treatment temperatures. However, in addition to the loss in wood mass, a strong influence of drying and softening of wood at elevated temperatures as well as an increased cell wall matrix stiffness by modification of the lignin carbohydrate complex under dry heat conditions influences the wood properties, i.e. water sorption. For wood thermally modified in open reactor systems at different peak temperatures and durations, the surface performance is investigated with regard to the susceptibility to surface cracking, photodegradation and coatability. The results provide explanations why the performance of thermally modified wood in exterior applications does not always meet the expectations derived from its enhanced resistance against decay fungi.
Author: Bahman Ghiassi Publisher: Woodhead Publishing ISBN: 0081021119 Category : Technology & Engineering Languages : en Pages : 422
Book Description
Long-Term Performance and Durability of Masonry Structures: Degradation Mechanisms, Health Monitoring and Service Life Design focuses on the long-term performance of masonry and historical structures. The book covers a wide range of related topics, including degradation mechanisms in different masonry types, structural health monitoring techniques, and long-term performance and service life design approaches. Each chapter reflects recent findings and the state-of-the-art, providing practical guidelines. Key topics covered include the theoretical background, transport properties, testing and modeling, protective measures and standards and codes. The book's focus is on individual construction materials, the composite system and structural performance. Covers all issues related to durability, including degradation mechanisms, testing and design, monitoring and service life design Focuses on different masonry construction types Presents a ‘one-stop’ reference for advanced postgraduate courses that focuses on the durability of masonry and historical constructions
Author: Callum A. S. Hill Publisher: John Wiley & Sons ISBN: 047002173X Category : Science Languages : en Pages : 260
Book Description
This book is exclusively concerned with wood modification, although many of these processes are generic and can be applied to other lignocellulosic materials. There have been many rapid developments in wood modification over the past decade and, in particular, there has been considerable progress made in the commercialisation of technologies. Topics covered include: The use of timber in the 21st century Modifying the properties of wood Chemical modification of wood: Acetic Anhydride Modification and reaction with other chemicals Thermal modification of wood Surface modification Impregnation modification Commercialisation of wood modification Environmental consideration and future developments This is the first time that a book has covered all wood modification technologies in one text. Although the book covers the main research developments in wood modification, it also puts wood modification into context and additionally deals with aspects of commercialisation and environmental impact. This book is very timely, because wood modification is undergoing huge developments at the present time, driven in part by environmental concerns regarding the use of wood treated with certain preservatives. There has been considerable commercial interest shown in wood modification over the past decade, with products based upon thermal modification, and furfurylation now being actively being marketed. The next few years will see the commercialisation of acetylation and impregnation modification. This is a new industry, but one that has enormous potential. This book will prove useful to all those with an interest in wood modification including researchers, technologists and professionals working in wood science and timber engineering, wood preservation, and well as professionals in the paper and pulp industries, and those with an interest in the development of renewable materials.
Author: Dick Sandberg Publisher: CRC Press ISBN: 1351028200 Category : Nature Languages : en Pages : 765
Book Description
The market for durable products using modified wood has increased substantially during the last few years. This is partly because of the restriction on the use of toxic preservatives due to environmental concerns, and to lower maintenance cost and time. Furthermore, as sustainability becomes a greater concern, the environmental impact of construction and interior materials is factored in planning by considering the whole life cycle and embodied energy of the materials used. Wood is modified to improve its intrinsic properties, enhance the range of applications of timber, and to acquire the form and functionality desired by engineers without calling the environmental friendliness into question. Wood modification processes are at various stages of development, and the challenges faced in scaling up to industrial applications differ. The aim of this book is to put together the key elements of the changes of wood constituents and the related changes in wood properties of modified wood. Further, a selection of the principal technologies implemented in wood modification are presented. This work is intended for researchers, professionals of timber construction, as well as students studying the science of materials, civil engineering and architecture. This work is not exhaustive, but intends to deliver an outline of the scientific disciplines necessary to apprehend the technologies of wood modification and its behavior during treatment, as well as during its use.
Author: Publisher: ISBN: Category : Languages : en Pages : 64
Book Description
The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Author: Publisher: ISBN: Category : Languages : en Pages : 56
Book Description
The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Author: Publisher: ISBN: Category : Languages : en Pages : 64
Book Description
The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Author: Michael Altgen
Author: Michael Altgen
Author: Bahman Ghiassi
Author: Callum A. S. Hill
Author: Dick Sandberg
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Author: Alfred J. Stamm
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