@article{SchaeferJagerSchwarzetal.2021, author = {Sch{\"a}fer, Jesco and Jager, Christopher and Schwarz, Ulrich and Winkler, Christoph}, title = {Improving the usability of piezoresistive bond lines in wood by using impedance measurements}, series = {Wood Science and Technology}, volume = {55}, journal = {Wood Science and Technology}, number = {4}, publisher = {Springer Nature}, issn = {0043-7719}, doi = {10.1007/s00226-021-01311-8}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-1942}, pages = {937 -- 954}, year = {2021}, abstract = {Various studies on wood adhesives filled with conductive fillers for future application to structural monitoring showed a piezoresistive (resistance change with strain) response of the adhesive bond lines that is measurable under direct current. The results also showed a relatively high signal noise with low sensitivity. Using impedance spectroscopy as a measurement technique, the improvements in frequency-dependent piezoresistivity over DC (Direct Current) resistography of multifunctional bonded wood were studied. Beech specimens were bonded by one-component polyurethane prepolymer (1C-PUR) filled with carbon black and tested under shear load. The quality of the piezoresistive properties was described by calculating the signal-to-noise ratio (SNR) of the measured signal. A setup-specific frequency band with optimized SNR between 100 kHz and 1 MHz could be derived from the measurements. Several frequencies showed a signal with higher quality resulting in a higher SNR. Regardless of the variations in impedance spectra for all specimens, this frequency band provided several frequencies with improved signal quality. These frequencies give a more reliable signal with lower noise compared to the signal from DC resistography.}, language = {en} } @article{WinklerHaaseSchwarzetal.2021, author = {Winkler, Christoph and Haase, Stefan and Schwarz, Ulrich and Jahreis, Markus}, title = {Piezoresistive bond lines for timber construction monitoring—experimental scale-up}, series = {Wood Science and Technology}, volume = {55}, journal = {Wood Science and Technology}, number = {4}, publisher = {Springer Nature}, issn = {0043-7719}, doi = {10.1007/s00226-021-01305-6}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-1959}, pages = {1379 -- 1400}, year = {2021}, abstract = {Several laboratory studies and experiments have demonstrated the usability of polymer films filled with electrically conductive filler as piezoresistive material. Applied to adhesives, the glue lines of wood products can achieve multifunctional—thus bonding and piezoresistive/strain sensing—properties. Based on critical load areas in timber constructions, upscaled test setups for simplified load situations were designed, especially with regard to a stress-free electrical contact. In a second step, another upscaling was done to small glulam beams. Based on an experimental test sequence, the piezoresistive reactions as well as the behaviour until failure were analysed. The results show in all cases that a piezoresistive reaction of the multifunctionally bonded specimens was measurable, giving a difference in the extent of relative change. Additionally, measured phenomena like inverse piezoresistive reactions, electrical resistance drift and the absence of a piezoresistive reaction were discussed, based on additional strain analysis by digital image correlation. A model of macroscopic and microscopic strains influencing the piezoresistive reaction of the electrically conductive bond line in wood was used to explain all experimental results. Finally, a first scale-up of piezoresistive bond lines from laboratory samples to glulam beams was possible and successful.}, 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} } @article{LoebjinskiRugPasternak2020, author = {Loebjinski, Maria and Rug, Wolfgang and Pasternak, Hartmut}, title = {The Influence of Improved Strength Grading In Situ on Modelling Timber Strength Properties}, series = {Buildings}, volume = {10}, journal = {Buildings}, number = {2}, publisher = {MDPI}, issn = {2075-5309}, doi = {10.3390/buildings10020030}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2736}, pages = {15}, year = {2020}, abstract = {The management and preservation of structures in our built environment are central and challenging tasks for practicing engineers. Within the CEN member states (European Committee for Standardization), the so-called Eurocodes form the basis of the design and verification of the load-bearing capacity of structures. Current Eurocodes do not contain special recommendations for existing structures, meaning that the principles for new structures are applied. This can lead to an incorrect estimation of the load-bearing capacity within the semi-probabilistic safety concept. A central task within the investigation and evaluation of existing structures is the strength grading of the material in situ using non-/semi-destructive technical devices. Studies show the potential of the ultrasonic time-of-flight measurement in combination with visual evaluation for an improved grading. The information on the material from an improved grading technique can be used to update the material parameters as a target variable using a measured reference variable. In this contribution, test data from a partner project (spruce, pine, and oak) are analyzed, applying the stochastic grading model of P{\"o}hlmann and Rackwitz. It can be shown that different grading techniques influence the updated distribution function of the material strength within the grade. The results depend on the timber species. Perspectives to develop updated models dependent on the knowledge available are shown and discussed.}, 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} } @article{WinklerKruegerSarnaghietal.2022, author = {Winkler, Christoph and Kr{\"u}ger, Robert and Sarnaghi, Ani Khaloian and Kluge, Patrick and van de Kuilen, Jan-Willem and Schwarz, Ulrich}, title = {Mechanische Eigenschaften von Sch{\"a}lfunierlagen in Sperrh{\"o}lzern}, series = {Holztechnologie}, journal = {Holztechnologie}, number = {1}, issn = {0018-3881}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4597}, pages = {25 -- 36}, year = {2022}, abstract = {In dieser Publikation wird der Frage nachgegangen, ob mit Klebstoff beschichtete Furniere gegen{\"u}ber nativen Furnieren geeigneter sind, um Kennwerte zur Berechnung und Simulation von Sperrh{\"o}lzern zu erhalten. Der Frage wurde mittels experimentellen Versuchen, analytischer Berechnung und Simulation nachgegangen und die Ergebnisse anhand von Buchenfurnier, teils beschichtet mit Phenol-Resorzin-Formaldehyd-Klebstoffen, dikutiert. Die Ergebnisse zeigen, dass beschichtete Furniere eine bessere {\"U}bereinstimmung mit BErechnungsans{\"a}tzen und Simulationen von Sperrh{\"o}lzern als native Furniere bieten und auch einem vereinfachten Ansatz eines Laminats aus Furnieren mit separaten Klebstoffschichten {\"u}berlegen sind.}, language = {de} } @article{CreydtLautnerFrommetal.2022, author = {Creydt, Marina and Lautner, Silke and Fromm, J{\"o}rg and Fischer, Markus}, title = {Wood profiling by non-targeted liquid chromatography high-resolution mass spectrometry: Part 2, Detection of the geographical origin of spruce wood (Picea abies) by determination of metabolite pattern}, series = {Journal of Chromatography A}, journal = {Journal of Chromatography A}, number = {1663}, publisher = {Elsevier}, issn = {1873-3778}, doi = {10.1016/j.chroma.2021.462737}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4925}, year = {2022}, abstract = {A non-targeted metabolomics-based approach using liquid chromatography high-resolution mass spectrometry was used to authenticate spruce wood (Picea abies) from two geographic source areas. The two sample sites were located in Germany and only 250 km apart. In order to achieve the highest possible metabolite coverage, the spruces samples were measured with four different methods using liquid chromatography high-resolution mass spectrometry. In this way, a total of approximately 4,100 features were detected, which included non-polar, polar, and intermediate-polar metabolites. Using supervised multivariate methods, a distinction between the two sample groups could be achieved on the basis of non-polar data sets. The major metabolites contributing to differentiation were identified by MS/MS experiments and were from the following classes of compounds: ceramides, fatty acids, glycerolipids, and phytosterols. Based on the soil descriptions of the two sites, it was concluded that there is probably a close relationship between nutrient availability and the differences in concentration of the marker compounds. The results show that a metabolomics-based approach is also suitable for differentiation of origin, even if the sample sites are close to each other.}, language = {en} }