@article{SanneAhnErcanPfriem2020, author = {Sanne, Moritz and Ahn-Ercan, Gudrun and Pfriem, Alexander}, title = {A Mathematical Solution for Calculating the Springback of Laminated Beech Stacks Molded within the Elastic Range}, series = {Forests}, journal = {Forests}, number = {11 (7)}, publisher = {MDPI}, issn = {1999-4907}, doi = {10.3390/f11070725}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2335}, pages = {12}, year = {2020}, abstract = {The springback effect in molded wood laminations within the elastic range has, to date, not yet been mathematically described. Once cured, residual internal stresses within the laminations cause the final form to deviate from that of the die. Test pieces of beech laminations of 1 mm, 2 mm and 4 mm thicknesses and stack sizes of between 2 and 16 laminations were used. The elasticity value of each stack was obtained using non-glued laminations in a three-point bending test within the elastic region. The laminations were glued with polyurethane resin and mounted in a radius form die. The stress induced by the die onto the stack is within the elastic region of the material without any prior chemical or physical plasticisation of the wood. After curing was complete and the laminations removed from the die, the actual radius was calculated using a circular equation within the CAD program, using three measurement points taken from the stack. The radius of the die within the limits of this study has a negligible effect when predicting the springback of the stack. The exponential correlation between springback and the number of laminations, was used to calculate the springback effect on molded laminated stacks.}, language = {en} } @article{MunierFrankeHeroldetal.2020, author = {Munier, Leo Felix and Franke, Tom and Herold, Nadine and Pfriem, Alexander}, title = {Humidity's Effect on the Dynamic-mechanical Behavior of Phenol-formaldehyde Impregnated Beech Wood Veneer}, series = {BioResources}, journal = {BioResources}, number = {15(1)}, doi = {10.15376/biores.15.1.1563-1574}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-3841}, pages = {1563 -- 1574}, year = {2020}, abstract = {The dynamic-mechanical behavior of phenol-formaldehyde-impregnated beech wood (Fagus sylvatica L.) veneers was evaluated at various relative humidities. The aim was to identify the plasticizing effects of moisture on phenol-formaldehyde-impregnated veneers. Thin beech veneer samples were impregnated with a low and a medium molecular weight phenol- formaldehyde resin. The measurements were performed with a dynamic- mechanical thermal analysis equipped with a humidity generator. The storage modulus and the loss factor of the uncured phenol-formaldehyde- impregnated and the untreated control veneers were determined at a relative humidity of 15\%, 60\%, and 85\% and a constant temperature of 25 °C. The untreated control veneers exhibited the smallest reduction of the normalized storage modulus. In contrast, the phenol-formaldehyde- impregnated samples exhibited a more intense relative reduction of the storage modulus with increasing relative humidity. This effect was more distinct for samples impregnated with low molecular weight phenol- formaldehyde than for those impregnated with medium molecular weight phenol-formaldehyde. In addition, higher solids contents in the resins led to even smaller normalized storage modulus. Consistently, the loss factor indicated a greater softening of the samples with an increasing humidity and higher solids content of the phenol-formaldehyde.}, language = {en} } @inproceedings{ClauderMunkPfriem2022, author = {Clauder, Lothar and Munk, Christoph and Pfriem, Alexander}, title = {The influence of thermal modification on the initial material-brightness (L*), documented by in-situ measurements}, series = {European Conference on Wood Modification 2022}, booktitle = {European Conference on Wood Modification 2022}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2801}, pages = {4}, year = {2022}, abstract = {In this study, the influence of the thermal modification on the characteristic brightness of the raw material Alder (Alnus rubra) and Maple (Acer pseudoplatanus) was investigated by spectral photometric in-situ analysis.}, language = {en} } @inproceedings{WozniakWulfPfriem2022, author = {Wozniak, Martin and Wulf, Fabian and Pfriem, Alexander}, title = {Investigation of a change in the hardness properties of thermally modified beech wood (Fagus sylvatica L) as a result of a 6-week long-term temperature at 120°C and 140°C}, series = {European Conference on Wood Modification 2022}, booktitle = {European Conference on Wood Modification 2022}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2816}, pages = {7}, year = {2022}, abstract = {The aim of this study is to investigate the mechanical properties and structural changes of wood during long-term tempering in mild temperatures. As a result of a long-term heat treatment on beech wood (Fagus sylvatica L), the degradation or decomposition reaction of wood-bound cellulose, hemicellulose and lignins in the low temperature range up to 150°C investigated. For this purpose, test series in the dry state are thermally treated over a period of 6 weeks at a temperature of 120°C and 140°C. Weekly, the mass and dimensions of the test specimens are recorded in order to effectively track the density curve. The mechanical resistance of the wood substrate was realized by a hardness measurement in a weekly period.}, language = {en} } @inproceedings{MunkClauderPfriem2018, author = {Munk, Christoph and Clauder, Lothar and Pfriem, Alexander}, title = {Acoustical comparison of two different guitars, made of untreated tropical wood and thermally modified wood, using a frequency response analysis}, series = {Northern European Network for Wood Science \& Engineering (WSE)}, booktitle = {Northern European Network for Wood Science \& Engineering (WSE)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2850}, year = {2018}, abstract = {To this day, many guitar makers around the world use primarily tropical woods such as rosewood (Dalbergia spp.) for their production. Due to the current CITES regulation of January 2017 regarding the trade of tropical woods, it becomes inevitable to generate alternative materials with similar material properties to be generated and established. Part of this study is an acoustic comparison of two guitars. One made of untreated tropical wood [Dalbergia nigra Benth.)] and one made of European thermally modified wood (TMT) species. [Pyrus (L.) and Alnus (Mill.)]. The method used allows a significant statement about the acoustic radiation performance of stringed and plucked instruments. The experimental setup consists of an impulse hammer for excitation of a force in the center of the bridge and a microphone for recording the signal radiated by the guitar body at a distance of one meter from the sound hole. A front-end was used to record the data, and further processing was done using analysis software to determine frequency response functions (FRFs) of the two instruments. The FRFs determined can be subdivided into several ranges which contain the different acoustic information about bass range, loudness, clarity, brightness and sharpness of the instruments. Examination of the frequency ranges reveals an acoustic similarity between the two guitars. Slight differences can be seen in the bass and loudness areas, where the guitar from TMT has a higher average level. Clearer differences are offered by the areas of clarity, where the guitar made of tropical wood shows a higher average level. In summary, the method gives an efficient acoustic impression as a function of the natural frequencies of the two guitars. The measured data show similarities and thus comparable acoustic properties of the instruments. However, additional effects such as psychoacoustic sensations or musical taste for the complete acoustic impression of an instrument are also of importance. Therefore, further empirical and fundamental research is needed to obtain a more detailed acoustic impression of the instruments.}, language = {en} } @inproceedings{MunkClauderPfriem2019, author = {Munk, Christoph and Clauder, Lothar and Pfriem, Alexander}, title = {Sound absorption coefficient of thermally modified and unmodified wood species measured in an impedance tube}, series = {Northern European Network for Wood Science and Engineering (WSE) - 15th Annual Meeting 2019}, booktitle = {Northern European Network for Wood Science and Engineering (WSE) - 15th Annual Meeting 2019}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2890}, year = {2019}, abstract = {Different parts of the guitar body are made of certain wood species, selected by their specific properties. The sound board, which is mainly made of spruce or cedar, transfers the vibration of the strings to the resonance body by means of the bridge. The sides and the back of the guitar rather reflect the sound of the acoustic vibrations and are predominantly made of tropical hardwoods like palisander, mahogany or ebony species. These species have limited availability and are listed on the CITES Annex I and II. To substitute tropical wood species, thermally modified European wood species with improved acoustic properties and dimensional stability may be used. Although the acoustic reflection of the sides and the back parts of a guitar body is an important property, there is not much knowledge about this reflection behaviour of wood. A few studies like the work of Hong (1989), Kang (2010) or Smardzewski et al. (2013) investigated the sound absorption properties of unmodified wood. Subsequently this study considers the sound absorption coefficients of unmodified and thermally modified European wood species in comparison to an unmodified tropical wood species.}, language = {en} } @inproceedings{MunkWohlertPfriem2021, author = {Munk, Christoph and Wohlert, Hauke and Pfriem, Alexander}, title = {Investigation of the influence of two different thermal treatment processes on the change of various material properties of spruce resonance wood (Picea abies (L.) Karst.)}, series = {Northern European Network for Wood Science and Engineering - 17th Annual Meeting 2021}, booktitle = {Northern European Network for Wood Science and Engineering - 17th Annual Meeting 2021}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2909}, pages = {3}, year = {2021}, abstract = {In recent years, a large number of different studies have shown that a variety of positive property changes can be achieved by thermally treating spruce resonance wood. Various methods have been established, which differ mainly in the choice of treatment atmosphere, but also in the associated treatment duration and temperature. Part of the present investigation was to compare a thermal-vacuum process with a process which takes place in an oxygen-reduced atmosphere, with regard to various property changes. The results show that both processes achieved similar results in terms of dynamic acoustic property changes. Larger differences were found with regard to moisture behavior and color change.}, language = {en} } @inproceedings{MunkPfriem2022, author = {Munk, Christoph and Pfriem, Alexander}, title = {Influence of thermal modification and subsequent linseed oil impregnation on the sound propagation velocity and related acoustic properties of various wood species}, series = {Tenth European Conference on Wood Modification}, booktitle = {Tenth European Conference on Wood Modification}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2916}, year = {2022}, abstract = {In the field of instrument making, the use of indigenous wood species is becoming more and more important due to the increasing environmental awareness of instrument makers and their customers. As the properties of some of these wood species cannot meet the high demands of this field of application, processes are being sought that can achieve improvements. In recent years, many studies have shown that different modification methods, such as furfurylation, thermal treatment, densification or impregnation methods, can partly improve wood properties such as elasticity, strength values, damping behaviour, but also moisture behaviour and wood moisture content significantly. The extent to which different modification processes and their positive changes in properties can be combined with each other and thus achieve further improvements will become increasingly important in the future, not only in instrument making but also in other areas of application. Therefore, this study investigated the influence of thermal treatment followed by linseed oil impregnation of wood on its sound propagation velocity and the associated acoustic properties of characteristic impedance and acoustic radiation.}, language = {en} } @inproceedings{MunkPfriem2022, author = {Munk, Christoph and Pfriem, Alexander}, title = {Influence of residual oxygen content during thermal modification process on mass loss, brightness colour and dynamic Young´s modulus of Fagus sylvatica (L.)}, series = {18th Annual Meeting of the Northern European Network for Wood Science and Engineering, 21-22 September 2022, G{\"o}ttingen, Germany}, booktitle = {18th Annual Meeting of the Northern European Network for Wood Science and Engineering, 21-22 September 2022, G{\"o}ttingen, Germany}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-3582}, pages = {1 -- 3}, year = {2022}, abstract = {The thermal modification of wood is considered to be an environmentally friendly and cost-effective treatment process, which has been able to establish itself in many areas of application due to its positive effect on a whole range of different material properties through a wide variety of process designs. In addition to heat transfer and pressure, closed and open systems differ primarily in the choice of treatment atmosphere mainly used to prevent combustion (Sandberg et al. 2021). Although many studies in recent years have investigated influencing process parameters such as temperature, pressure or treatment duration, there exists a knowledge gap regarding the influence of the treatment atmosphere or its behaviour during the treatment process (Candelier et al. 2016). Therefore, this study aims to analyse different oxygen-nitrogen concentrations in the treatment atmosphere at different residual oxygen levels during the process duration and their influence on different property parameters of Fagus sylvatica (L.).}, language = {en} } @inproceedings{BenderMunkDamayetal.2022, author = {Bender, Tobias and Munk, Christoph and Damay, J{\´e}r{\´e}mie and Jousserand, Michael and G{\´e}rardin, Philippe and Pfriem, Alexander}, title = {The Effect of Thermal Treatment of Sycamore Maple (Acer Pseudoplatanus L.) prior to Impregnation with Furfuryl Alcohol, regarding Homogeneity and Swelling Behaviour}, series = {18th Annual Meeting of the Northern European Network for Wood Science and Engineering, 21-22 September 2022, G{\"o}ttingen, Germany}, booktitle = {18th Annual Meeting of the Northern European Network for Wood Science and Engineering, 21-22 September 2022, G{\"o}ttingen, Germany}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-3597}, pages = {1 -- 1}, year = {2022}, abstract = {Impregnation of wood with certain chemical compounds is a well established method to improve its physical and mechanical properties. However, the result is often not quite homogeneous. This study examines the effect of two varying thermal treatments on the impregnability of sycamore maple (Acer Pseudoplatanus L.) with furfuryl alcohol (FA), and on the resulting Anti-Swelling-Efficiency (ASE).}, language = {en} } @inproceedings{WozniakWulfMunieretal.2022, author = {Wozniak, Martin and Wulf, Fabian and Munier, Leo Felix and Mund, Axel and Pfriem, Alexander}, title = {Reduce, Reuse, Recycle im M{\"o}belsektor}, series = {Tagungsband des 20. Holztechnologischen Kolloquiums Dresden 28.-29. April 2022}, booktitle = {Tagungsband des 20. Holztechnologischen Kolloquiums Dresden 28.-29. April 2022}, editor = {Wagenf{\"u}hr, Andr{\`e}}, publisher = {Selbstverlag TU Dresden}, address = {Dresden}, isbn = {978-3-86780-705-0}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2760}, pages = {79 -- 87}, year = {2022}, abstract = {Aufgrund von Rohstoffknappheit auch bei nachwachsenden Rohstoffen kann das Recyceln von Holz und Holzwerkstoffen auch im M{\"o}belsektor nur an vorletzter Stelle, vor der thermischen Verwertung, stehen. Davor gilt es, schon bei der Produktion den Materialeinsatz zu reduzieren bzw. M{\"o}bel so zu gestalten, dass eine verl{\"a}ngerte Nutzung m{\"o}glich ist. Insgesamt muss die Produktnutzung intensiviert werden. Daf{\"u}r sind unter anderem geeignete Businessmodelle erforderlich. Hiermit besch{\"a}ftigt sich das Projekt PERMA an der HNEE. Wird Holz dann zum Altholz, muss die Nachnutzungsquote deutlich erh{\"o}ht werden. Mit der Identifizierung und Indexierung von Altholz befasst sich daher das Kooperations-projekt WIn-Altholz. Sind allerdings Holzspan- und Holzfaserwerkstoffe besch{\"a}-digt oder werden nicht mehr ben{\"o}tigt, gibt es bisher keine sinnvollen Nachnut-zungsszenarien. Das Forschungsprojekt „Respan" will nun ein Recyclingverfahren entwickeln, dass die Nachnutzung m{\"o}glichst aller Bestandteile der Werkstoffe realisiert.}, language = {de} } @misc{SanneKampeLenzetal.2020, author = {Sanne, Moritz and Kampe, Anja and Lenz, Claudia and Gossel, Stefan and Wagner, Sabine and Haibel, Astrid and Melcher, Eckhard and Leu, Carsten and Pfriem, Alexander and Lautner, Silke}, title = {Introduction of shock wave technology to fir wood preservation}, series = {International Wood Products Journal}, volume = {12}, journal = {International Wood Products Journal}, number = {1}, publisher = {Taylor \& Francis}, issn = {2042-6445}, doi = {10.1080/20426445.2020.1838215}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4536}, pages = {3 -- 6}, year = {2020}, abstract = {Similar to a normal wave, a shock wave travels as energy through matter but it causes an abrupt rise of pressure, temperature and density. In this study, the influence of shock waves on wood structure were investigated in the light of possible future industrial utilization e.g. timber impregnating treatment. The constructed autoclave is capable of creating shock waves either by an electrical pulse breakdown of a spark gap arrangement or by electromagnetic actuators. The penetration depths of the fir wood test samples were measured using light microscopy, SEM and micro-computed tomography. Our results showed that by varying the intensity of the incident shock wave, the distance between the shock wave generating device and the test sample, and/or the orientation of test sample in relation to the shockwave, the wood tissue structure had been heavily disintegrated or hardly affected at all. An improvement on impregnation could not be found.}, language = {en} } @article{PopescuPfriem2020, author = {Popescu, Carmen-Mihaela and Pfriem, Alexander}, title = {Treatments and modification to improve the reaction to fire of wood and wood based products—An overview}, series = {Fire and Materials}, volume = {44}, journal = {Fire and Materials}, number = {1}, publisher = {Wiley}, issn = {0308-0501}, doi = {10.1002/fam.2779}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4541}, pages = {100 -- 111}, year = {2020}, abstract = {Wood and wood-based products are widely used for structural building elements, but due to their composition, they are susceptible of combusting if exposed to fire. Fire safety is an important issue of building safety, especially when the building's fire load contents enhance the risks of fire spread. Therefore, the involved materials are very important to address the fire safety requirements. When existing timber structures are involved, the most usual way to improve its reaction to fire is to treat wood with fire retardant materials. The idea of this paper is to give an overall overview, on the existing fire-retardant and intumescent coating materials, modification, and treatments that can be applied to wood and wood-based products in order to improve their reaction to fire.}, language = {en} } @article{SanneMunierFoersteretal.2020, author = {Sanne, Moritz and Munier, Leo Felix and F{\"o}rster, Theresa and Dreyer, Christian and Pfriem, Alexander}, title = {Einfluss der Schlichte von Celluloseregeneratsfasern auf die Zugscherfestigkeit bei Holzverklebungen}, series = {Holztechnologie}, volume = {61}, journal = {Holztechnologie}, number = {5}, issn = {0018-3881}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4560}, pages = {38 -- 42}, year = {2020}, abstract = {Es wurden L{\"a}ngszugscherversuch an mit Celluloseregenaratfaser (CRF) verst{\"a}rktem Epoxidharz durchgef{\"u}hrt. Dabei wurden die Festigkeiten von CRF mit und ohne Schlichtemittel verglichen. Die dauerhafte Ausbildung eines stabilen Verbundes zwischen CRF und Epoxidharz ist weiterhin problematisch. Der Einsatz eines Schlichtemittels wirkt sich nicht auf die Verklebbarkeit der Fasern in der Matrix aus. Sowohl die Werte des Zugscherversuchs als auch die makroskopischen Bruchbilder und die mikroskopischen Analysen von Rissen in der Matrix zeigen keine nennenswerten Unterschiede zwischen beiden untersuchten Varianten.}, language = {de} } @article{FriedrichLuetjeFournetGengnageletal.2021, author = {Friedrich, Jan and L{\"u}tje-Fournet, Lucas and Gengnagel, Christoph and Pfriem, Alexander}, title = {Brandschutztechnische Ert{\"u}chtigung von Holzoberfl{\"a}chen durch Pyrolyse: Verbesserung der brandhemmenden Wirkung von pyrolysierten Fassadenh{\"o}lzern}, series = {Holztechnologie}, volume = {62}, journal = {Holztechnologie}, number = {2}, issn = {0018-3881}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4579}, pages = {23 -- 35}, year = {2021}, abstract = {Im Rahmen des Forschungsprojektes PyroForCE wurde untersucht, inwieweit sich das Brandverhalten von Fassadenh{\"o}lzern alleine durch die Erzeugung einer oberfl{\"a}chlichen Pyrolyseschicht so ver{\"a}ndern l{\"a}sst, dass dadurch die Anforderungen f{\"u}r eine Klassifizierung als schwerentflammbarer Baustoff dauerhaft erf{\"u}llt werden. Hierzu wurde eine kontinuierlich arbeitende Holzpyrolyseanlage entwickelt, mit der reproduzierbare Pyrolysefl{\"a}chen auf Pr{\"u}fk{\"o}rpern der Holzarten Eiche, L{\"a}rche und Fichte erzeugt werden konnten. Durch eine zus{\"a}tzliche Stabilisierung mit Natriumwasserglas lassen sich sowohl die oberfl{\"a}chliche Abriebfestigkeit erh{\"o}hen als auch die Brandschutzwirkung verbessern. So modifizierte Fassadenh{\"o}lzer k{\"o}nnen im Single-Burn-Item-Test eine Klassifikatione als "schwerentflammbares" Bauprodukt erreichen. Damit ist das Ziel erreicht, nur durch Oberfl{\"a}chenpyrolyse in VErbindung mit einer Stabilisierung durch rein mineralische Wassergl{\"a}ser das Brandverhalten von Fassadenh{\"o}lzern so zu ver{\"a}ndern, dass eine Zuordnung zu den schwerentflammbaren Baustoffen erreicht werden kann und diese damit als Fassadenmaterial im st{\"a}dtischen Kontext und der Geb{\"a}udeklasse 4 und 5 einsetzt werden d{\"u}rfen.}, language = {de} } @article{MensahAhiekporHeroldetal.2022, author = {Mensah, Isaac and Ahiekpor, Julius Cudjoe and Herold, Nadine and Bensah, Edem Cudjoe and Pfriem, Alexander and Antwi, Edward and Amponsem, Bright}, title = {Biomass and plastic co-pyrolysis for syngas production: Characterisation of Celtis mildbraedii sawdust as a potential feedstock}, series = {Scientific African}, journal = {Scientific African}, number = {16}, publisher = {Elsevier}, issn = {2468-2276}, doi = {10.1016/j.sciaf.2022.e01208}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4588}, pages = {9}, year = {2022}, abstract = {Celtis mildbraedii sawdust (CMS) from Ghana was characterised to investigate its suitability with polyethylene terephthalate (PET) for syngas production via co-pyrolysis. The physical and chemical properties assessed include proximate and ultimate compositions, pH value, higher heating value (HHV), and lignocellulosic composition. Also, the thermal behaviour at different heating rates (5, 10, and 20 K/min) and qualitative prediction of organic compounds of CMS were examined using thermogravimetric analysis (TG/DTG) and NIR spectroscopy techniques, respectively. Results of proximate analysis (moisture = 17.15 ± 0.0 wt.\%, ash = 1.13 ± 0.4 wt.\%, volatile matter = 68.39 ± 0.4 wt.\%, fixed carbon = 13.33 ± 0.8 wt.\%); ultimate analysis (C = 48.51 wt.\%, H = 6.66 wt.\%, N = 0.51 wt.\%, S = 0.02 wt.\%, O = 44.30 wt.\%); pH values (cold phase = 7.60, hot phase = 6.30); HHV (15.37 - 18.03 MJ/kg); and lignocellulosic composition (extractives = 13.80 ± 0.57 wt.\%, hemicellulose = 21.95 ± 3.89 wt.\%, lignin = 17.35 ± 0.35 wt.\%, cellulose = 46.90 ± 2.97 wt.\%) were obtained. The maximum mass loss was 83.48\% at 289.8 °C at 5 K/min. It was concluded that CMS is a highly potential biomass resource for syngas production with an empirical formula of CH1.64O0.69N0.009S0.0001.}, language = {en} } @inproceedings{LenzGolleeKuehnetal.2023, author = {Lenz, Claudia and Gollee, Paul and K{\"u}hn, Michael and Leich, Christian and Pfriem, Alexander}, title = {Artificial irradiation (indoors) of European wood species at different irradiation intensities and at different temperatures}, series = {Proceedings of the 19th Meeting of the Northern European Network for Wood Science and Engineering (WSE) 10-12 October 2023}, booktitle = {Proceedings of the 19th Meeting of the Northern European Network for Wood Science and Engineering (WSE) 10-12 October 2023}, editor = {Larn{\o}y, Erik}, publisher = {Published with support from SNS - The Nordic Forest Research Cooperation Commitee}, address = {{\AA}s, Norway}, doi = {10.57741/opus4-765}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-7654}, pages = {125 -- 127}, year = {2023}, abstract = {The background of the topic is to compare the colour changes at different irradiances and temperatures at constant relative humidity. The issue is important because evaluation in terms of irradiance has not been studied in more detail. Irradiation intensities were reported in many studies but tended to have metadata status. The concrete influence of the irradiance on chemical and colour changes in the wood remains open. This paper presents an approach to inquiry-based teaching within a basic research project. Initial results from a large-scale data series are presented here. Irradiance is the term for the total power of incoming electromagnetic energy striking a surface, related to the size of the area, measured in watts per square metre [W/m²].}, language = {en} } @inproceedings{FrankeLenzHertrichetal.2016, author = {Franke, Tom and Lenz, Claudia and Hertrich, Sven and Kehr, Martin and Kuhnert, Niklas and Munier, Leo Felix and Schultz, Marcus and Stepputat, S{\"o}ren and Herold, Nadine and Pfriem, Alexander}, title = {K{\"u}nstliche Bewitterung von Buchenfurnier (Fagus sylvatica) impr{\"a}gniert mit drei Phenolharzen unterschiedlichen Molekulargewichts}, doi = {10.57741/opus4-760}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-7609}, pages = {1}, year = {2016}, language = {de} } @misc{LenzWolffBeyeretal.2023, author = {Lenz, Claudia and Wolff, Ian and Beyer, Mario and Koch, Gerald and Pfriem, Alexander}, title = {DMP: Predictability of color changes of wood used indoor - A new approach to evaluate the colour change as a function of the radiation dose. Research Data Management Questionnaire}, doi = {10.5281/zenodo.8084673}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-8237}, pages = {47}, year = {2023}, abstract = {This is a data management plan for the DFG research project "Predictability of color changes of wood used indoor - A new approach to evaluate the color change as a function of the radiation dose". DFG Funding code / Project number: 442135169 Project website: https://gepris.dfg.de/gepris/projekt/442135169?language=en This data management plan (DMP) applies to the Research Data Management Organizer (RDMO) questionnaire and was operated with the RDMO software: https://rdmorganiser.github.io/en/}, language = {en} } @inproceedings{WolffLenzPanitzetal.2023, author = {Wolff, Ian and Lenz, Claudia and Panitz, Michael and Pfriem, Alexander}, title = {Chart for the Core Objectives of Data Publishing within Technical Infrastructure for Research Data Management}, doi = {10.5281/zenodo.8388953}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-8240}, pages = {1}, year = {2023}, abstract = {Academic data stewardship at universities has to fulfil many different roles. One of the most important is to build up a connection to researchers and bridge the gap between research data infrastructure and researchers. Different scientific communities have different requirements for research data management and expectations regarding text and data publication. In many of the sub-disciplines of engineering sciences, research data management practices are not established so far. When it comes to contact between data stewards and researchers, a common knowledge base has to be established to become clear about why and what actions for research data management has to take, that engineering researchers can adapt them for their research data management practices. Many research data management standards have to take into consideration. However, to this point of time, the research data management community lacks for data literacy graphics to explain how the technical data management ecosystem works together with standards like the findability, accessibility, interoperability and reuse (FAIR) principles. Therefore, we developed a graphic for data literacy and consulting scenarios.}, language = {en} } @misc{NoeltingDembskiFritzetal.2021, author = {N{\"o}lting, Benjamin and Dembski, Nadine and Fritz, Hilke and Kr{\"a}usche, Kerstin and Lehmann, Kerstin and Molitor, Heike and Pape, Jens and Pfriem, Alexander and Seichter, Cosima Zita and Walk, Heike}, title = {Handreichung: Nachhaltigkeitstransfer in der Lehre}, editor = {Hochschule f{\"u}r nachhaltige Entwicklung Eberswalde,}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-6414}, pages = {20}, year = {2021}, abstract = {Diese Handreichung kn{\"u}pft an diese Fragen an: Sie zeigt auf, wie durch Nachhaltigkeitstransfer Lehr-Lern-Prozesse in lebensweltliche Kontexte eingebettet werden k{\"o}nnen. Transfer findet unserer Erfahrung nach bereits in vielf{\"a}ltiger Form Eingang in die Lehre. Aber h{\"a}ufig fehlen Zeit, Ressourcen und Ansatzpunkte, um Transfer systematisch zu planen, umzusetzen und ihn so zu gestalten, dass er zu nachhaltiger Entwicklung beitragen kann.}, language = {de} } @inproceedings{SanneKampeLenzetal.2017, author = {Sanne, Moritz and Kampe, Anja and Lenz, Claudia and Gossel, Stefan and Wagner, Sabine and Haibel, Astrid and Melcher, Eckhard and Leu, Carsten and Pfriem, Alexander and Lautner, Silke}, title = {Anatomical studies of wood treated with pressure pulse shock waves}, series = {Proceedings of the 13th annual meeting of the Northern European Network for Wood Science and Engineering (WSE2017)}, booktitle = {Proceedings of the 13th annual meeting of the Northern European Network for Wood Science and Engineering (WSE2017)}, editor = {Engelund Thybring, Emil}, doi = {10.57741/opus4-684}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-6841}, pages = {1}, year = {2017}, abstract = {Similar to a normal wave, a shock wave travels as energy through matter but it causes an abrupt raise of pressure, temperature and density. In this study the influence of shock waves on wood structure were investigated in the light of possible future industrial utilization e.g. timber impregnating treatment.}, language = {en} } @inproceedings{LenzKochPfriem2024, author = {Lenz, Claudia and Koch, Gerald and Pfriem, Alexander}, title = {Analyse von bestrahlten, unbehandelten Holzoberfl{\"a}chen mittels UV-Mikrospektralphotometrie (UMSP)}, series = {Tagungsband 6. Holzanatomisches Kolloquium}, booktitle = {Tagungsband 6. Holzanatomisches Kolloquium}, editor = {Dresden, IHD}, address = {Dresden}, organization = {TU Dresden}, doi = {10.57741/opus4-892}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-8921}, pages = {122 -- 130}, year = {2024}, abstract = {Das DFG-Forschungsprojekt „Vorhersagbarkeit der Farb{\"a}nderungen von Holz im Innenbereich - Die Auswertung in Abh{\"a}ngigkeit von der Strahlungsdosis als neuer Ansatz" besch{\"a}ftigt sich mit den Farbver{\"a}nderungen der Oberfl{\"a}chen von in Mitteleuropa wachsenden Holzarten. Die optischen Eigenschaften des Holzes sind sehr unterschiedlich und im Wesentlichen abh{\"a}ngig von den im Holz vorhandenen chromophoren funktionellen Gruppen (z.B. phenolische Hydroxylgruppen, Doppelbindungen, Carbonylgruppen) und chromophoren Systemen (Chinone, Chinomethide, Biphenyle) (Hon 2001; Rowell et al. 2012). Sowohl zwischen verschiedenen Arten als auch innerhalb einer Holzart gibt es zum Teil erhebliche Farbschwankungen. Eine ver{\"a}nderte Lichtbrechung durch Strukturmerkmale wie Dreh- und Wechseldrehwuchs hat auch Einfluss auf das optische Erscheinungsbild. Farb{\"a}nderungen treten bereits beim Trocknen oder D{\"a}mpfen der H{\"o}lzer auf (Aydin und Colakoglu 2005). Zudem ver{\"a}ndert sich die Farbe der Oberfl{\"a}che sowohl beim Auftragen von transparenten Oberfl{\"a}chenbeschichtungen („Anfeuerung des Holzes") und durch Kombination von beidem. Licht ist der sichtbare (englisch: visible (Vis)) Teil des elektromagnetischen Spektrums, neben weiteren Spektralbereichen wie ultravioletter (UV) und infraroter (IR) Strahlung. UV-, VIS- und IR-Strahlung haben als Teile des Sonnenstrahlungsspektrums eine energetische Wirkung auf Holzoberfl{\"a}chen. Die Farb{\"a}nderungen bei nat{\"u}rlicher Alterung werden durch Strahlung von UV-, VIS- und IR-Licht und der dadurch induzierten Photooxidation hervorgerufen (Hon und Chang 1982; Feist und Hon 1984; Hon und Minemura 2001). Zur optischen und chemischen Erfassung der Ver{\"a}nderungen der Holzoberfl{\"a}chen wurden in dem Projekt u.a. Farbmessungen im CIE L*a*b*-Farbraum (DIN EN ISO/CIE 11664-4:2020-03), abgeschw{\"a}chte Totalreflexions-Fourier-Transformations-Infrarot-Spektroskopie (ATR-FTIR) und Spektroskopie im ultraviolett-visuellen Bereich (UV-Vis)sowie regelm{\"a}ßige Farbscans der Probenoberfl{\"a}chen durchgef{\"u}hrt. Zudem wurden die Methoden der Gaschromatographie mit Massenspektrometrie-Kopplung (GC- MS) und die zellul{\"a}re UV-Mikrospektralphotometrie (UMSP) angewandt. Letzte wird im Folgenden n{\"a}her erl{\"a}utert. Koch 2004 f{\"u}hrte umfangreiche, topochemische Untersuchungen {\"u}ber Inhaltsstoffe im Holzgewebe und deren Bedeutung f{\"u}r die Holzverf{\"a}rbung durch. Die grundlegenden Untersuchungen zur fakultativen (an Fagus sylvatica L.) und obligatorischen (an Prunus serotina Borkh.)Farbkernbildung beinhaltete die UMSP-Methode. Damit k{\"o}nnen aromatische Verbindungen in einzelnen Zelltypen und Zellwandschichten hochaufl{\"o}send, topochemisch detektiert werden. Zudem ist eine qualitative Charakterisierung bzw. Reaktionen von Inhaltsstoffen {\"u}ber UV-Spektren vor und nach einer Sonnenlicht-Simulation m{\"o}glich. Mit Hilfe der zellul{\"a}ren UV-Mikrospektralphotometrie k{\"o}nnen aromatische Verbindungen (Lignin, phenolische Extraktstoffe) in einzelnen Zellwandschichten bei einer Aufl{\"o}sung von 0,25 μm x 0,25 μm lokalisiert werden. Die qualitative Charakterisierung von Inhaltsstoffen erfolgt {\"u}ber die Aufnahme von UV/Vis- Spektren im Wellenl{\"a}ngenbereich von 240 bis 700 nm (Messbereich f{\"u}r das UMSP 80, siehe Kapitel 2). Durch das spektroskopische Fl{\"a}chen-Scanning k{\"o}nnen die Verteilung und semi-quantitative Konzentration von Lignin und phenolischen Extraktstoffen graphisch dargestellt werden (Koch et al. 2003, Koch und Kleist 2001). Vor allem die genaue Visualisierung der farbgebenden Komponenten in den unterschiedlichen Zelltypen und Zellwandschichten sowie deren {\"A}nderung durch die Sonnenlicht-Exposition liefert weitere grundlegende Erkenntnisse {\"u}ber die photochemischen Reaktionen im Holzgewebe. F{\"u}r die chemische Charakterisierung der Stoffe k{\"o}nnen zudem Punktmessungen mit einer Aufl{\"o}sung von 1 μm² durchgef{\"u}hrt werden. Diese UV/Vis-Extinktionsspektren werden in einem Wellenl{\"a}ngenbereich von 240 bis 580 nm aufgenommen. Ein Absorptionsmaximum im Wellenl{\"a}ngenbereich von 276 bis 280 nm ist z.B. typisch f{\"u}r aromatische und konjugierte Verbindungen. Nach Koch 2004 entstehen mit zunehmender Trocknungstemperatur h{\"o}herkondensierte Verbindungen, die durch eine starke Verschiebung der Absorptionsmaxima in den l{\"a}ngerwelligen Spektralbereich und insgesamt h{\"o}heren Absorptionswerten charakterisiert werden. Diese Reaktionsmechanismen erkl{\"a}ren auch das Farbverhalten des Holzes bei l{\"a}ngerer Lichteinstrahlung, durch die ein intensives Nachdunkeln (Lichtalterung) einsetzt. Aufgrund der erheblichen Datens{\"a}tze von bis zu 60.000 Messpunkten f{\"u}r jedes Scanning-Feld (Gr{\"o}ße ca. 50 μm x 50 μm) wird die Auswertung der topochemischen Analysen im Gesamtvorhaben exemplarisch auf drei Holzarten und zwei Schnitttiefen mit vier Messzeitpunkten pro Setup und Behandlung (unbehandelt/extrahiert) reduziert. Die UMSP-Methode findet seither in vielen Bereichen der Holzanalytik Anwendung, z.B. in der Holzbiologie und in der Holzchemie (Andersons et al. 2016, Biziks et al. 2020, Ehmcke et al. 2020, Lewandrowski et al. 2022, R{\"u}ggeberg et al. 2008, Schmitt et al., 2015, etc.)}, language = {de} } @inproceedings{MunkBiewerDamayetal.2024, author = {Munk, Christoph and Biewer, Raphael and Damay, J{\´e}r{\´e}mie and Jousserand, Michael and G{\´e}rardin, Philippe and Pfriem, Alexander}, title = {Acoustic properties of thermally treated and furfurylated European hardwood species}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-9864}, pages = {1 -- 3}, year = {2024}, abstract = {Three hardwood species, including alder (Alnus glutinosa), sycamore maple (Acer pseudoplatanus) and hornbeam (Carpinus betulus), were analyzed for changes in their acoustic properties due to thermal treatment (TM), furfurylation (FU) and a combination of both types of treatment (TF). TM was carried out in a nitrogen atmosphere at 200 °C for 4 hours. For FU, a solution of 85\% furfuryl alcohol, 10\% water and 5\% tartaric acid was used, which was impregnated in a vacuum pressure process, followed by polymerization at 120 °C for 16 hours. For each wood species, one test group was left as an untreated reference, the other groups were treated according to the treatment types TM, FU and TF. Per group 10 samples were tested using experimental modal analysis. Due to the orthotropy of the wood, the acoustic parameters dynamic modulus of elasticity (E), damping and sound radiation coefficient were determined in both the longitudinal and radial directions. The results show that TM slightly decreases longitudinal E for all three species and slightly increases radial E for maple and hornbeam. FU and TF strongly increase the E in the radial direction, especially for maple and alder. For all three species the damping is reduced by TM, more in the radial direction than in the longitudinal direction. FU and TF increase the damping in the longitudinal direction, mainly for maple and alder, but also reduce it in the radial direction. The sound radiation coefficient is reduced by FU and TF for all three species, particularly in the longitudinal direction. However, in both the longitudinal and radial directions, TM slightly increases the sound radiation coefficient for all three species. The anisotropy ratio of the longitudinal/radial E of all three species is reduced by FU and TF, whereas TM has no significant effect on it.}, language = {en} }