Characterization of hemp fiber fire reaction

Integrating bio-resources in materials allows to reduce the environmental impact of the building industry. This study deals with fire-retardant treatments, alternative to boric acid and ammonium salts solutions, applied to hemp fibers for thermal insulation application. The aim is to limit the energy, sanitary and environmental impacts of the treatment, while optimizing the technical performances. A laboratory protocol evaluates the flame-retardant effect of the developed treatments. Treated fibers, including commercial treatments, are subjected to characterization tests: direct ignition small flame, thermal analysis (thermogravimetric analysis [TGA], differential thermal analysis [DTA]), pyrolysis-combustion flow calorimeter and cone calorimeter. Some of the methods have been adapted to be applied to fibrous materials. The obtained results orientate the formulation of a treatment and highlight the complementarity of the analysis methods. Coupling the results, the ConeTools's predictive model leads to the estimation of the reaction to fire class according to the Euroclass. Euroclass C appears accessible with a tailored treatment.     

Image-Based Flow Regime Recognition in Aerated Stirred Tanks Using Deep Transfer Learning

Monitoring of flow regimes in aerated stirred tanks is important to ensure energy efficiency and product quality. The use of deep learning models for the recognition of flow regimes shows promising results. However, such models require a large amount of data for training. The aim of this paper is to apply the deep transfer learning approach to address this challenge. We compare various pre-trained models with the differential learning rate and 2-step transfer learning approaches to analyse the resultant model performance. We also investigate the effect of the dataset size on the classification accuracy.     

Automated Evaluation of Biochemical Plant KPIs based on DEXPI Information

Implementation of data-based key performance indicators (KPIs) within existing plants usually requires a thorough manual analysis of the plant topology to define which sensors could provide reliable information for calculating the KPIs. In this publication, we propose an assistance system that automates this process. First the automatic linkage between plant structure and operational data is presented for the evaluation of the process efficiency. Next, a concept and prototypical implementation of the evaluation of predefined KPIs is described. The plant structure is described according to the DEPXI specification, while a rule-based framework was developed to depict the process-engineering knowledge. The proposed methods have been validated in an experimental setup. It could be shown that with standardized inputs, a generic extendable evaluation of the plant performance can be achieved.     

An Advanced ‘clickECM’ That Can be Modified by the Inverse-Electron-Demand Diels-Alder Reaction

The extracellular matrix (ECM) represents the natural environment of cells in tissue and therefore is a promising biomaterial in a variety of applications. Depending on the purpose, it is necessary to equip the ECM with specific addressable functional groups for further modification with bioactive molecules, for controllable cross-linking and/or covalent binding to surfaces. Metabolic glycoengineering (MGE) enables the specific modification of the ECM with such functional groups without affecting the native structure of the ECM. In a previous approach (S. M. Ruff, S. Keller, D. E. Wieland, V. Wittmann, G. E. M. Tovar, M. Bach, P. J. Kluger, Acta Biomater. 2017 , 52, 159–170), we demonstrated the modification of an ECM with azido groups, which can be addressed by bioorthogonal copper-catalyzed azide-alkyne cycloaddition (CuAAC). Here, we demonstrate the modification of an ECM with dienophiles (terminal alkenes, cyclopropene), which can be addressed by an inverse-electron-demand Diels-Alder (IEDDA) reaction. This reaction is cell friendly as there are no cytotoxic catalysts needed. We show the equipment of the ECM with a bioactive molecule (enzyme) and prove that the functional groups do not influence cellular behavior. Thus, this new material has great potential for use as a biomaterial, which can be individually modified in a wide range of applications.     

Immobilization of Lipoxygenase,Catalase, and Lipase for a Reactor Design Targeting Linoleic Acid Hydroperoxidation

Hydroperoxy-9Z,11E-octadecadienoic acid (13-HPODE) can be obtained from safflower oil in an enzyme cascade utilizing lipase, lipoxygenase (LOX), and catalase for in situ oxygen generation. The application of immobilized enzymes may open a new path to a cost-efficient production of 13-HPODE, which is used for the synthesis of green note aroma hexanal. Ten immobilization supports are compared for immobilization of lipoxygenase-1 from Glycine max (LOX-1) and oxirane-based Immobead 150 P proves to be best with a maximum LOX-1 activity of 22 470 U g⁻¹. The immobilizate is successfully recycled in eight consecutive batches and maintains full activity over a period of 16 h using a 3D-printed column reactor. Catalase from Micrococcus lysodeikticus and LOX-1 are co-immobilized on Immobead 150 P allowing a constant production of 13-HPODE for up to six cycles with a maximum product conversion of 45% and a 13-regioselectivity of 83% . In this two-enzyme system with H₂O₂-dosage, foam generation is significantly reduced. Co-immobilization of LOX-1 and lipaseis possible; however, rapid lipase deactivation occurs. Therefore, a two-reactor approach with oil hydrolysis in the first reactor is proposed. Immobilized lipases from C. rugosa are suitable for safflower oil hydrolysis and maintain full activity over ten hydrolysis cycles. Practical applications: Linoleic acid hydroperoxide (13-HPODE) is the starting material for the synthesis of the green note aroma compound hexanal. The byproduct of the hydroperoxide splitting is ω-oxododecenoic acid, which is currently not employed industrially. The bifunctional oxodocecenoic acid is interesting as precursor for the synthesis of polymer building blocks. Simple one-step derivatization of the oxo-group can yield suitable C12 monomers such as dicarboxylic acids, ω-amino acids, or ω-hydroxy acids. Cost-efficiency is a key parameter to incorporate these new biobased building blocks for polymer applications. In this approach, immobilized enzymes are used for the synthesis of 13-HPODE starting from safflower oil with in situ oxygen generation to prevent excessive foam formation. A two-reactor concept is designed to circumvent hydroperoxide-induced lipase deactivation. Direct comparison of both batch and continuous process is performed and provides information for the implementation of the enzyme cascade and the design of an optimized reactor system.