70 research outputs found
A Simple Approach to Distinguish Classic and Formaldehyde-Free Tannin Based Rigid Foams by ATR FT-IR
Tannin based rigid foams (TBRFs) have been produced with formaldehyde since 1994. Only recently several methods have been developed in order to produce these foams without using formaldehyde. TBRFs with and without formaldehyde are visually indistinguishable; therefore a method for determining the differences between these foams had to be found. The attenuated total reflectance infrared spectroscopy (ATR FT-IR) investigation of the TBRFs presented in this paper allowed discrimination between the formaldehyde-containing (classic) and formaldehyde-free TBRFs. The spectra of the formaldehyde-free TBRFs, indeed, present decreased band intensity related to the C–O stretching vibration of (i) the methylol groups and (ii) the furanic rings. This evidence served to prove the chemical difference between the two TBRFs and explained the slightly higher mechanical properties measured for the classic TBRFs
Analysis of plant materials pre-treated by steam explosion technology for their usability as insulating materials
ArticleRaw materials of annual plants fibres are not easily usable for industrial production
applications. Pre-treatment of the annual plant fibres is necessary to increase the homogeneity of
the material and to improve the material properties. This study deals with the influence of steam
explosion treatment on the quality of annual plant fibres used as insulating material.
Maize and wheat straw were selected for production of insulating panels. To clarify the changes
within the structure of the plants due to the pre-treatment process material analysis was carried
out using FT-IR spectroscopy and raster electron microscope. Furthermore, the bulk density and
the thermal conductivity were analysed as important values for insulating materials.
The results showed that the pre-treatment process homogenizes the materials and the processes
could be used for the production of bulk insulation
Sustainable Phenolic Fractions as Basis for Furfuryl Alcohol-Based Co-Polymers and Their Use as Wood Adhesives
Pollutant absorption as a possible end-of-life solution for polyphenolic polymers
Tannin- and lignin-furanic foams are natural porous materials that have attracted high
interest in the scientific and industrial communities for their high thermal and fire-resistant properties.
However, no interesting solutions have been proposed for the management of their end-life as yet.
In this study, the phenolic-furanic powders derived from the foams were analyzed for their capacity
to remove dierent pollutants like neutral, cationic, and anionic organic molecules from wastewater.
It was observed that the macromolecules produced from initially bigger fractions were more suitable
to remove methylene blue and sodium dodecyl sulfate (SDS) while contained absorptions were
observed for riboflavin. Acidified tannin powders were also prepared to understand the role of
the flavonoid in the absorption mechanism. The latter showed outstanding absorption capacity
against all of the tested pollutants, highlighting the key-role of the flavonoid fraction and suggesting
the limited contribution of the furanic part. All adsorbents were investigated through FT-IR and
solid state 13C-NMR. Finally, the powders were successfully regenerated by simple ethanol washing,
showing almost complete absorption recovery
Computers and Electronics in Agriculture / Towards the applicability of biometric wood log traceability using digital log end images
Log traceability in the timber based industries is a basic requirement to fulfil economical, social and legal requirements. This work introduces biometric log recognition using digital log end images and explores the robustness to a set of log end cross-section (CS) variations. In order to investigate longitudinal and surface CS variations three tree logs were sliced and captured in different sessions. A texture feature-based technique well known from fingerprint recognition is adopted to compute and match biometric templates of CS images captured from log ends. In the experimental evaluation insights and constraints on the general applicability and robustness of log end biometrics to identify logs in an industrial application are presented. Results for different identification performance scenarios indicate that the matching procedure which is based on annual ring pattern and shape information is very robust to log length cutting using different cutting tools. The findings of this study are a further step towards the development of a biometric log recognition system.(VLID)223160
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Microstructure of viscoelastic thermal compressed (VTC) wood using computed microtomography
The paper describes for the first time the analysis of the structure of compressed wood using computed tomography. The anatomical structures of Douglas-fir and hybrid poplar before and after densification with the Viscoelastic Thermal Compression (VTC) process were described by pore size distributions and mean pore sizes and compared. The compression of Douglas-fir mainly affected earlywood, while the compression of hybrid poplar mainly occurred in the vessels. In both wood species the densification resulted in a significant decrease in the pore volumes. The porosity decreased to less than the half of the original value for Douglas-fir earlywood
and to approximately one quarter for the vessels in hybrid poplar. The relevant mean pore sizes also decreased dramatically down to about one quarter compared to the original values. In contrast, latewood in Douglas-fir and libriform fibers in hybrid poplar are quite stable under compression. Douglas-fir latewood retained its original structure after compression and did not show any reduction in pore size.
The results confirmed that the anatomical structure of VTC densified wood can be described by pore size distributions and mean pore sizes. However, in the case of broad or bimodal distributions the mean pore sizes are of less significance.Keywords: Pore size distribution, Computed microtomography, Image analysis, VTC wood, Granulometry, PorosityKeywords: Pore size distribution, Computed microtomography, Image analysis, VTC wood, Granulometry, Porosit
Improving CT image analysis of augmented bone with raman spectroscopy
In recent years, bone graft substitutes have been increasingly used in the medical field, for example, in order to promote new bone formation. Microcomputed tomography (-CT) is an image-guided technique used in medicine as well as in materials science, enabling the characterization of biomaterials with high spatial resolution. X-ray-based methods provide density information; however, the question how far conclusions on chemical structures can be inferred from any kind of CT information has not been intensively investigated yet. In the present study, a bone sample consisting of autogenous bone derived cells (ABCs) and bovine bone mineral (BBM) was investigated by -CT and Raman spectroscopic imaging, that is, by two nondestructive imaging methods. Thereby, the image data were compared by means of regression analysis and digital image processing methods. It could be found that 51.8% of the variance of gray level intensities, as a result of -CT, can be described by different Raman spectra of particular interest for bone composition studies by means of a multiple linear regression. With the better description of -CT images by the linear model, a better distinction of different bone components is possible. Therefore, the method shown can be applied to improve CT-image-based bone modeling in the future
Phenotyping patients with ischaemic heart disease at risk of developing heart failure: an analysis of the HOMAGE trial
Aims: We aim to characterize the clinical and proteomic profiles of patients at risk of developing heart failure (HF), with and without coronary artery disease (CAD) or prior myocardial infarction (MI). Methods and results: HOMAGE evaluated the effect of spironolactone on plasma and serum markers of fibrosis over 9Â months of follow-up in participants with (or at risk of having) CAD, and raised natriuretic peptides. In this post hoc analysis, patients were classified as (i) neither CAD nor MI; (ii) CAD; or (iii) MI. Proteomic between-group differences were evaluated through logistic regression and narrowed using backward stepwise selection and bootstrapping. Among the 527 participants, 28% had neither CAD or MI, 31% had CAD, and 41% had prior MI. Compared with people with neither CAD nor MI, those with CAD had higher baseline plasma concentrations of matrix metalloproteinase-7 (MMP-7), galectin-4 (GAL4), plasminogen activator inhibitor 1 (PAI-1), and lower plasma peptidoglycan recognition protein 1 (PGLYRP1), whilst those with a history of MI had higher plasma MMP-7, neurotrophin-3 (NT3), pulmonary surfactant-associated protein D (PSPD), and lower plasma tumour necrosis factor-related activation-induced cytokine (TRANCE). Proteomic signatures were similar for patients with CAD or prior MI. Treatment with spironolactone was associated with an increase of MMP7, NT3, and PGLYRP1 at 9Â months. Conclusions: In patients at risk of developing HF, those with CAD or MI had a different proteomic profile regarding inflammatory, immunological, and collagen catabolic processes
Tannin- caprolactam and Tannin- PEG formulations as outdoor wood preservatives: Weathering properties
International audienceAbstractKey messageThis article presents the leaching, fire and weathering resistance improvements of samples treated with tannin-based wood preservatives added of caprolactam. PEG-added formulations show limited applicability. The FT-IR and13C-NMR analyses of the caprolactam-added formulations show some evidences of copolymerization.ContextTannin-boron wood preservatives are known for their high resistance against leaching, biological attacks, fire as well as for the good mechanical properties that they impart to wood. These properties promoted these formulations for being a candidate for the protection of green buildings. However, the low elasticity of these polymers and their dark colour implied limited weathering resistances.AimsThe aim of the study is to find suitable additives for tannin-based formulations to overcome their limited weathering resistances, without compromising the other properties.MethodsTreatment, leaching and fire tests, dimensional stability as well as artificial and natural weathering of the timber treated with caprolactam-added and PEG-added formulations were performed. FT-IR and 13C-NMR of the formulations were presented.ResultsThe presence of caprolactam improved the properties of the formulation with particularly significant results in terms of resistance against leaching and dimensional stability. These enhancements were imparted also to the weathering resistance of the tannin-caprolactam formulations. Indeed, the colour changes during the artificial and natural exposures were stable for longer periods. FT-IR and 13C-NMR investigations of the advanced formulations were led, and covalent copolymerization of the caprolactam with the tannin-hexamine polymer was observed.ConclusionThe tannin formulations with caprolactam improved the durability of the wood specimens, while the PEG-tannin presented strong application drawbacks
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