[article-cris] Kemian tekniikan korkeakoulu / CHEM

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  • Acoustic performance optimization of natural-fiber micro-perforated panels backed by an optimized polyurethane–fibrogranule composite
    (2026-02-09) Nakhaeipour, Mojtaba; Forouharmajd, Farhad; Habibi, Ehsanollah; Soltani, Parham; Tehrani, Ali
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Noise pollution poses a major threat to public health and urban sustainability, necessitating effective and environmentally compatible acoustic solutions. Here we report a high-performance hybrid absorber that integrates a natural-fiber micro-perforated panel (MPP) fabricated from alkali-treated flax and rice husks with an optimized polyurethane–fibrogranule (PU-FG) composite backing reinforced by the same renewable fillers. Using response surface methodology based on central composite design, we systematically optimized composite formulation, panel porosity, and air-gap geometry to achieve superior broadband absorption. The resulting system, a 1.61% porosity MPP, 28.5 mm front air gap, 40 mm PU-FG backing, and a 30 mm rear air gap, achieves a sound absorption average (SAA) of 0.82 and a noise reduction coefficient (NRC) of 0.85 across the frequency range 100–2500 Hz. This configuration provides effective broadband absorption through the combined action of Helmholtz resonance from the MPP and visco-thermal losses in the porous backing. Morphological analysis via field-emission scanning electron microscopy confirms hierarchical pore structures enhancing tortuosity and interfacial adhesion. By substantially increasing the renewable content of both the MPP and the porous backing, this lightweight, high-efficiency hybrid offers a practical and scalable pathway toward more sustainable noise-control materials for architectural, transportation, and urban applications.
  • Engineered phytic acid-lignin networks: one-pot strategy toward stable, multifunctional bio-based materials
    (2026-03) Bagheri, Marzieh; Farooq, Muhammad; Nousiainen, Paula; Hyväkkö, Uula; Österberg, Monika
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    This study introduces a one-pot approach that covalently links phytic acid into the lignin network while preserving lignin's ability to self-assemble into nanoparticles. Using diepoxy reagent and ethyl levulinate as crosslinkers, covalent bonding was achieved and confirmed via lignin model compounds experiments. The resulting phytic acid-modified lignin exhibited promising self-extinguishing behavior, retained lignin's antioxidant activity (IC50 of 0.1 g/l), and could be converted into stable nanoparticles via solvent shifting, thus broadening the application portfolio. These self-assembled spherical phytic acid-modified lignin nanoparticles (P-LNPs) with an average size of 140 ± 5 nm demonstrated high surface charge of -64.5 mV at pH 7, efficient cationic pollutant adsorption (62.9 mg/g adsorption capacity achieved instantly), and antifogging properties. This work presents a stable lignin-phytic acid system that can be used directly or as aqueous dispersion of nanoparticles, enabling a variety of applications and establishing a scalable framework to transform lignin into a high-value platform material.
  • Demonstrating the Performance of Aspartic-Acid Functionalized Naphthalene Diimide in a Near-Neutral Flow Battery
    (2026-02-08) Shahsavan, Mahsa; Wiberg, Cedrik; Hamza, Andrea; Poskela, Aapo; Hjelm, Johan; Peljo, Pekka
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The performance of the negatively charged aspartic acid-functionalized naphthalene diimide (ASP-NDI) in a flow battery is investigated in this article. The high concentration ASP-NDI/ferrocyanide flow battery presented cycled for 79.8 days with an average coulombic efficiency of 99.9% and an energy efficiency of 87.5% at 20 mA cm−2 while accessing an over 90% of the theoretical capacity of ASP-NDI with a capacity fade rate of 0.0275% per day that is the lowest reported for the NDI-based flow batteries to date.
  • Improved capabilities of the TurboGAP code for radiation induced cascade simulations : An illustration with silicon
    (2026-03-10) Saha, Uttiyoarnab; Hamedani, Ali; Caro, Miguel A.; Sand, Andrea E.
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    TurboGAP is a software package designed for efficient molecular dynamics simulations using Gaussian approximation potential (GAP) machine-learning interatomic potentials (MLIP). In this work, we enhance the capabilities of TurboGAP for radiation damage simulations by implementing a two-temperature molecular dynamics model, based on electron density-dependent coupling of electronic and atomic subsystems. Additionally, we implement adaptive calculation of the timestep and grouping of atoms for cell-border cooling. Our implementation incorporates electronic stopping power either through a traditional friction-based model or a more realistic first-principles-derived model. By combining the computational efficiency of TurboGAP with the accuracy of GAP MLIP, we perform cascade simulations in silicon with primary knock-on atom (PKA) energies up to 10 keV. Our simulations scale to systems containing up to 1 million atoms. We study the generation and clustering of radiation-induced defects. We also calculate ion-beam mixing and compare our results with the experimental data, discussing how the GAP-MLIP along with the inclusion of a realistic electronic stopping model affects the prediction of experimental mixing values.
  • Lithium-ion batteries recycling: Review of reactor and process design, scalability, cost, and environmental performance
    (2026-04-01) Benaabidate, Safae; El Mounafia, Nabil; Rahimpour, Saeed; Fogarasi, Szabolcs; Lasri, Karima; Wilson, Benjamin P.; Cormos, Ana-Maria; Taha, Yassine; Hakkou, Rachid; Saadoune, Ismael; Zaabout, Abdelghafour
    A2 Katsausartikkeli tieteellisessä aikakauslehdessä
    Various methods are being explored to recover valuable metals from spent lithium-ion batteries (SLIBs), particularly those with LiNixCoyMnzO2 (x + y + z = 1) (NMC) cathode materials composed of critical metals Ni, Co, and Li. Methods being investigated are primarily based on hydrometallurgy, pyrometallurgy, hybrid, and direct cathode regeneration. Key studies focus primarily on increased recovery rates and maximized selectivity towards targeted products. However, such methods involve complex reactive multiphase flow phenomena requiring perfect understanding and adaptation of existing knowledge to the battery recycling context beyond lab scale experiments and associated performance. This work reviews and analyzes various recycling methods, focusing on the chemical engineering aspects, targeting accelerated upscaling of promising ones towards an industry with maximized cost-effectiveness and minimized environmental impacts. The analyses revealed very scattered technical, economic, and environmental data, with a lack of standardized assessment frameworks, making it difficult to make any clear judgment on the performance of the different proposed methods. Guidelines for streamlined technological maturation are presented and discussed. The proposal includes holistic, integrated assessment approaches in standardized frameworks that align the interplaying aspects of chemical engineering, such as thermodynamics, kinetics, and multiphase flow dynamics, with targeted techno-economic and life cycle performance. Such an approach can be used as an effective tool for screening promising technology at an early stage of development to identify the one to prioritize for faster scale-up. This can guarantee reducing research and development costs and ultimately de-risking investments to drive the scale-up and industrial deployment.
  • Mining metal from waste
    (2026-02-16) Pirrie, Duncan; Donnelly, Laurance J.; Power, Matthew R.; Butcher, Alan R.; Menzies, Andrew; Jolis, Ester M.; Wilson, Ben P.
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    With the transition to a low carbon future and increasing technological applications, the global demand for metals will continue to rise into the foreseeable future. However, primary ore deposits are finite, and to continue production, lower grade and more complex ore deposits need to be discovered, evaluated and exploited, with increasing exploration and production costs. Additionally, there are significant geopolitical constraints on global resources for some critical raw materials and metals, along with ethical constraints of ‘off-shoring’ minerals supply to areas of the world with poor records in terms of legal mineral production, human rights violations, health and safety, and the long-term environmental impact of mining. Whilst it is unlikely at present to be able to fully meet supply needs, one source of metals for the future is through recycling of both domestic and industrial waste. Modern waste streams such as end-of-life lithium-ion batteries and electrical waste commonly contain significantly more metals than primary ore deposits before processing. However, these waste materials are complex, and through two case studies in this article, we focus on how methods commonly used in modern mining and mineral processing can be used to assist the processing and recovery of metals from waste. Perhaps it is time to reclassify waste as valuable resources for the future.
  • Resolving DNA origami structural integrity and pharmacokinetics in vivo
    (2026-02) Wang, Yang; Rocamonde-Lago, Iris; Waldvogel, Janine; Shen, Boxuan; Wu, Yi-Chia; Zhu, Junke; Zang, Shuya; Jia, Yingbo; Baars, Igor; Kloosterman, Alexander; Hoffecker, Ian T.; Wu, Ming-Ru; He, Qin; Högberg, Björn
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    DNA origami holds great potential for advancing therapeutics, but the lack of methods for the precise assessment of structural integrity in vivo prevents its translation. Here we introduce proximity ligation assay for structural tracking and integrity quantification (PLASTIQ) for resolving origami structural integrity with only 1 µl of blood sample and with a detection limit of 0.01 fM. Through PLASTIQ, we could observe and quantify the dynamics of DNA origami degradation during blood circulation and evaluate the effectiveness of PEGylation for slowing this process in a murine model. Additionally, by using a double-layered barrel-like origami structure, we found distinct degradation kinetics of DNA helices depending on their specific location, revealing the slower degradation of internal helices compared with the outer ones. Our results suggest that PLASTIQ offers a quantitative approach for assessing DNA origami integrity in vivo by longitudinal sampling, providing dynamic pharmaceutical-level insights for accelerating the development of DNA-nanostructure-based therapeutic molecules and drugs.
  • Atomic layer deposition of zinc oxide films on lateral high-aspect-ratio test structures using diethylzinc and water as precursors
    (2026-03-04) Haimi, Eero; Philip, Anish; Velasco, Jorge A.; Gao, Feng; Karppinen, Maarit; Puurunen, Riikka L.
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Zinc oxide is a wide bandgap semiconductor with a variety of applications as a thin film material. In this work, a set of zinc oxide thin films were grown on lateral high-aspect-ratio test structures using atomic layer deposition. Diethylzinc and water were used as precursors, and several processing conditions were examined. The grown films were characterized for conformality using energy-dispersive electron probe x-ray microanalysis supported by x-ray reflectometry studies of additional reference samples. To analyze growth kinetics and film thickness profiles, diffusion-reaction simulations were made. Most importantly, it was found that at the 200 °C growth temperature, the film thickness profile followed nearly perfectly the ideal saturation profile expected for self-terminating reactions. The obtained result, thus, establishes an excellent reference case for process optimization.
  • Liquid–Liquid Extraction of Acetic Acid with 2-Methyltetrahydrofuran: Experiments, Process Modeling, and Economics
    (2026-02-04) Laitinen, Antero T.; Parsana, Vyomesh M.; Khirsariya, Priyank; Jauhiainen, Olli; Huotari, Marco; Pokki, Juha-Pekka; Vlugt, Thijs J.H.; Ramdin, Mahinder
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Acetic acid production from renewable processes such as biomass hydrolysis and electrochemical reduction of CO2 exhibits low concentrations, which make downstream separation challenging. We measured the vapor–liquid equilibria of the binary systems acetic acid + 2-methyltetrahydrofuran (2-MTHF), methyl-t-butyl ether (MTBE) + acetic acid, and the ternary liquid–liquid equilibria of the system 2-MTHF + AA + water, fitted the data to the UNIQUAC-HOC and NRTL models, designed a hybrid extraction-distillation process for acetic acid separation with 2-MTHF, and evaluated its economics and compared with that of three other commonly used solvents (i.e., ethyl acetate, MTBE, and methyl propyl ketone). The lowest and highest costs of separation were observed for MTBE and MPK, while 2-MTHF and EA showed similar performance. The cost of separation increased exponentially as the feed concentration decreased, and renewable processes should aim for at least 5 wt % acetic acid in the feed to allow economically feasible separation.
  • A Machine Learning-Guided Study of Structure-Reactivity Relationships in Diels-Alder Cycloadditions
    (2026-01-23) Mahdian, Amir; Farshadfar, Kaveh; Laasonen, Kari
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The Diels-Alder cycloaddition is a cornerstone transformation in organic synthesis and has been extensively studied in both experimental and theoretical contexts. In this work, we present a complementary computational approach that combines density functional theory (DFT) and machine learning to further elucidate the role of steric and electronic effects in determining the reactivity and activation barriers. A diverse dataset of 1000 uncatalyzed hydrocarbon Diels-Alder reactions was used to train predictive models that relate activation energies to chemically meaningful molecular descriptors. SHAP analysis of the machine learning models highlights the dominant influence of steric effects, particularly those associated with substituent volume at the internal diene carbons, which can impose conformational strain and lead to significantly elevated barriers. In contrast, substituents at the terminal positions have a more limited impact. We introduced the minimum energy gap between LUMOdiene-HOMOdienophile and LUMOdienophile-HOMOdiene as a key predictive descriptor. This feature shows a strong correlation with the activation energy across the dataset, although steric interactions can lead to notable deviations from the overall trend. The resulting models provide insights for rationalizing selectivity and designing more efficient cycloadditions based on steric and electronic complementarity.
  • Synthesis and characterisation of bio-derived furan-based polyamides copolymers from dimethyl furan-2,5-dicarboxylate
    (2026) Paganelli, Zoe; Välinen, Lauri; Hanafi, Onsi; Hirvonen, Sami-Pekka; Baniasadi, Hossein; Niskanen, Jukka
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Polymers and plastics play integral roles in everyday life due to their versatility and durability. Among them, polyamides are particularly valued for their excellent properties and broad range of applications. The study explores the synthesis and characterisation of bio-derived polymers copolymers. Specifically, polyamides and copolyamides have been successfully synthesised from dimethyl furan-2,5-dicarboxylate and two diamines, hexamethylene diamine and 1,10-decanediamine, by employing a new three-step method. Key findings include the successful polymerisation of polyamides and copolyamides with a molecular weight up to 26 900 g mol−1 while demonstrating robust thermal stability, withstanding up to 403.7 °C. In addition, the mechanical properties, such as elastic modulus, of these amorphous polyamides and copolyamides were found to be comparable to commercial polyamides. Notably, the variation of molar ratios of diamines greatly influences the final properties of the polyamides and copolyamides, offering insight into customising mechanical, thermal, and physical qualities of the polymer. This research contributes significantly to the advancement of sustainable polymer solutions, positioning bio-derived polyamides as viable substitutes to mitigate reliance on fossil fuels while enhancing environmental sustainability.
  • Decoupling H-Release and OH– Management at Pd@TiO2 Interfaces for Efficient Alkaline Hydrogen Oxidation Reaction
    (2026-02-20) Jin, Benjin; Kallio, Antti Jussi; Rieger, Nils; Marchuk, Vasyl; Schiwek, Cedric; Shi, Junjie; Sainio, Jani; Jiang, Hua; Hammouali, Amine; Koivuniemi, Jefina A.S.; Han, Nana; Wickman, Björn; Huotari, Simo; Kallio, Tanja
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Operando-level insight into catalyst degradation and reaction mechanisms is essential for progress in the alkaline hydrogen oxidation reaction (HOR). Herein, these aspects are investigated using a core–shell Pd@TiO2/C catalyst synthesized by thermal reduction followed by atomic layer deposition. The obtained catalyst exhibits high stability and delivers a mass exchange current density (j0,m) of 97.5 mA mgPd–1, more than three times that of uncoated Pd/C (27.5 mA mgPd–1). Identical location transmission electron microscopy reveals a growth–detachment degradation pathway for Pd/C during accelerated durability testing, whereas the TiO2 shell in Pd@TiO2/C effectively suppresses this degradation, resulting in enhanced structural stability. Operando X-ray absorption spectroscopy under device-relevant conditions demonstrates the complementary functions of the two components: hydrogen dissociates and forms PdHx on the Pd core, lowering its Fermi level and driving electron transfer from TiO2 to Pd, while the TiO2 shell facilitates hydrogen desorption and provides OH– adsorption sites, thereby accelerating the reaction kinetics. These findings elucidate the dual stabilizing and catalytic roles of TiO2 and suggest a promising strategy for the design of durable and efficient alkaline HOR catalysts.
  • Crystal Properties and Hydrate Formation of Phytostanols and Phytosterols
    (2026-02-04) Översti, Paula; Han, Bing; Rautama, Eeva-Leena; Kavakka, Jari; Torssell, Staffan; Oinas, Pekka; Louhi-Kultanen, Marjatta
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Phytosterols, and their saturated analogs phytostanols, exist in different hydrated forms known as monohydrate (ca. 4 wt % water), hemihydrate (ca. 2 wt % water), and anhydrate (0 wt % water), all having different properties. In the current research, the solid-state characteristics of phytosterols and phytostanols were studied, with a focus on the hydrate formation and stability. The solid-state analysis was conducted using powder XRD, TGA, DSC, elemental analysis, and SEM. To the best of our knowledge, this is the first time that crystal lattice and unit cell parameters of β-sitostanol have been investigated. Surprisingly, we observed that different hydrate forms can be modified solely by adjusting the drying and storage conditions of the crystals. This implies that the crystallization conditions themselves, especially the solvent system, can be chosen based purely on crystal purity, preferred particle specifications and yield obtained. Anhydrous phytosterols are more stable against atmospheric moisture when stored at ambient conditions compared to anhydrous phytostanols, which absorb moisture remarkably quickly, within as little as an hour. The findings regarding the differences in stability and hygroscopicity tendencies are important aspects for storage and usage of the material in further applications.
  • High-sensitivity, protein-independent detection of dsDNA sequences
    (2026-02-04) Yan, Jiaqi; Bhadane, Rajendra; Xu, Wentao; Ran, Meixin; Ma, Xiaochao; Li, Yuanqiang; Jahnke, Kevin; Ma, Xiaodong; Salo-Ahen, Outi M.H.; Kostiainen, Mauri A.; Weitz, David A.; Zhang, Hongbo
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Current methodologies for detecting the sequence of double-stranded DNA (dsDNA) require amplifying and denaturing the target into single-stranded DNA (ssDNA) to enable sequence detection through Watson–Crick base pairing. However, these approaches are limited by the risks of nonspecific amplification, reliance on complex, temperature-sensitive protein enzymes, and harsh reaction conditions, such as in strong base or acidic environments. Here, we introduce a dsDNA detection platform that integrates a peptide nucleic acid (PNA) as the dsDNA denaturation agent, with multicomponent deoxyribozyme as the ssDNA detection tool, in a droplet-based system. This protein- and amplification-free method offers single-nucleotide resolution, detects down to a single dsDNA molecule, and delivers results within 1 h at room temperature. This work introduces a conceptually unique approach, that may be useful for both diagnostics and therapeutics.
  • An integrated cell and medium engineering approach for production of a nanobody fusion in Saccharomyces cerevisiae
    (2026-01-30) Niemelä, Laura R.K.; Kirjavainen, Lotta-Mari; Kozlowski, Hendrikje C.J.; Salminen, Heidi; Frey, Alexander D.
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Saccharomyces cerevisiae is an established production host for therapeutic proteins; many of those are small proteins such as insulin or glucagon-like peptide-1 (GLP-1) analogs. Contrastingly, proteins of higher molecular weight, foremost antibodies, did not reach the market due, among other factors, to limiting productivity. Here we addressed the loss of product to protein degradation through a combination of genetic engineering of the host and medium optimization. We screened target genes that either directly or indirectly can lead to proteolytic degradation. We identified four deletions that are beneficial for expression: PEP1 and VPS30, which both can channel proteins to the vacuole for degradation; MON2, which can lead to the re-uptake of secreted proteins; and ALG3, which can affect the permeability of the cell wall. In parallel, we developed a small-scale fed-batch cultivation system for 24-well deep well plate cultivations and using an amino acid-rich medium. To stabilize secreted proteins, we screened chemical chaperones and osmolytes. We fortified the medium with arginine, 4-phenylbutyrate (4-PBA), and Tween-20. Using the engineered yeast strain, which features VPS30, PEP1, and ALG3 deletions, and the small-scale fed-batch system, we obtained 2.5 µg/mL of a secreted chimeric fusion of a nanobody to the crystallizable fragment (Fc) of a human immunoglobulin. Instrumental to the increase in the final titer were the reduced losses. This was achieved by a combination of complementary measures: improving diffusion through the cell wall, achieved through genetic engineering, and reducing losses to proteolytic degradation through medium optimization and genetic engineering. Moreover, we showed that the engineered strain and cultivation set-up are suitable for the production of different antibodies. 
  • PRecTimber 2.0: Forecasting quantitative and qualitative potentials for wood circularity in Germany, Finland, and Sweden
    (2026-03-15) Mahenthren, Vijhay Krisshna; Weber-Blaschke, Gabriele; Hughes, Mark; Risse, Michael
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    National bioeconomy strategies in Germany, Finland, and Sweden are expected to increase wood demand, putting pressure on already strained forest resources. Circularity of wood products can reduce this demand by improving resource efficiency, but barriers like uncertain availability and quality of post-consumer wood hinder implementation. This study optimizes and extends the PRecTimber model to forecast post-consumer wood quantities and qualities in Germany (revised with quality information), Finland, and Sweden. By 2050, predicted post-consumer wood volumes are 14.11 Mt in Germany, 1.64 Mt in Finland, and 2.74 Mt in Sweden, mainly from the construction sector. Our quality assessment methodology with scenario analysis (status quo S0 and improved scenarios S1–S2 with +10 and +20 percentage-point gains in key quality factors) reveals that the shares of post-consumer construction sawnwood suitable for lifespan extension and material recycling, respectively, are 25 % and 59 % under S0, 36 % and 50 % under S1, and 49 % and 38 % under S2. Leveraging these quantity and quality insights, policy reforms can support industries and technological innovation to optimize the use of post-consumer wood.
  • Design and in vitro validation of Brome mosaic –virus-like particles for gene delivery and immunomodulation of melanoma
    (2026-02) Elbadri, Khalil; Fusciello, Manlio; Hamdan, Firas; Cheng, Ruoyu; Feola, Sara; Bokharaie, Honey; D'Amico, Carmine; Molinaro, Giuseppina; Correia, Alexandra; Wang, Shiqi; Jeltsch, Michael; Cerullo, Vincenzo; Santos, Hélder A.
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    RNA interference (RNAi) is a powerful tool for post-transcriptional gene silencing, yet its clinical translation remains limited by the lack of safe and efficient delivery systems. In this study, we evaluated the potential of plant virus-like particles (VLPs), derived from Brome Mosaic Virus (BMV), as a biodegradable and biocompatible nanocarrier for small interfering RNA (siRNA) delivery aimed at modulating immune checkpoints in melanoma. Recombinant BMV capsid proteins were expressed in E. coli and self-assembled in vitro into uniform VLPs encapsulating siRNA directed against the programmed death-ligand 1 (PD-L1). The VLPs displayed high structural stability, efficient siRNA encapsulation, and excellent biocompatibility. In vitro, A high cellular uptake was confirmed by confocal microscopy and flow cytometry. Besides, no cytotoxicity was observed and functional siRNA delivery was demonstrated in vitro by knockdown of eGFP in macrophages and PD-L1 in B16F10 melanoma and JAWS II dendritic cells, with significant knockdown efficiencies comparable to controls. Beyond molecular knockdown, PD-L1 silencing mediated by BMV-VLPs induced functional immunomodulation, increasing CD8⁺ T-cell–mediated cytotoxicity in melanoma and CMT64 tumor models and enhancing allogeneic T-cell proliferation in dendritic cell–based mixed leukocyte reactions. Overall, these findings indicate that plant-derived BMV-VLPs can safely mediate RNA-based checkpoint modulation and could complement antibody-based PD-1/PD-L1 blockade strategies. Owing to their intrinsic biocompatibility, scalability, and modular design, BMV-VLPs represent a sustainable and versatile alternative to synthetic lipid systems for RNA immunotherapy.
  • Thermal conductivity of used copper converter bricks
    (2026-03) Pankka, Iida; Tammela, Joonas; Taskinen, Pekka; Lindberg, Daniel
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Peirce-Smith converters are commonly used in copper smelting and have a refractory lining of MgO-based bricks. There are multiple possible sources of refractory degradation, one of which is the thermal stress generated during operation. This is thought to be aggravated by the infiltration of metal into the brick structure, which is believed to increase the thermal conductivity of the refractory. In this work, 10 postmortem magnesia-chrome refractory bricks taken from a Peirce-Smith converter in Boliden Harjavalta were studied using laser flash analysis, thermodynamic modeling utilizing FactSage software, and mineralogical observations. Slag interaction was found to have occurred at the hot face of several bricks. Infiltration of metal and matte was found to increase the thermal conductivity of the brick, but the difference between samples with and without metal/matte infiltration was not as significant as expected. The thermal conductivity of the postmortem bricks without metal/matte infiltration was found to be 3–4 W/(m·K) at 800 °C, whereas the thermal conductivity of samples with metal/matte infiltration was found to be between 3 W and 6 W/(m·K) at 800 °C.
  • Phase equilibria in the system Fe-Cu-Sn-FeO at iron saturation
    (2026-05) Anto, Bayu; Klemettinen, Lassi; Taskinen, Pekka; Kurhila, Matti; Tiljander, Mia; Lindberg, Daniel
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The equilibria between tin and ferrous oxide were approached at 1100–1300 °C by experiments using copper‑tin alloys as sources of tin. The experiments were carried out in closed iron ampoules sealed with laser welding to avoid tin and tin oxide volatilization during equilibration. The phase composition analyses were conducted by electron probe X-ray microanalysis for the major and minor components and laser ablation-inductively coupled plasma-mass spectrometry for the trace concentrations directly from polished sections. The copper‑iron‑tin phase diagram was measured at FeO saturation up to 20 wt% Sn in the liquid copper alloy. The thermodynamic properties of tin and copper in solid iron were evaluated. Additionally, the dissolution of tin and copper in ferrous oxide was measured at iron saturation.
  • Amido-Amine Co(II) Precursor-Based Atomic/Molecular Layer Deposition Processes for Cobalt-Organic Thin Films and Their Thermal Conversion to CoO Thin Films
    (2026-01-31) Jussila, Topias; Obenlüneschloß, Jorit; Liu, Ji; Partanen, Olga; Vasala, Sami; Rogalla, Detlef; Glatzel, Pieter; Nolan, Michael; Devi, Anjana; Karppinen, Maarit
    A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Atomic/molecular layer deposition (ALD/MLD) offers a comprehensive process and application portfolio for metal–organic thin films; however, ALD/MLD process development for transition-metal-based materials remains very limited, despite the versatile functional properties of their compounds. In this work, to enrich the chemistry of transition metal precursors in ALD/MLD, an all-nitrogen-coordinated cobalt complex, Co(tmsaedma)2 (tmsaedma = Bis(N,N-dimethyl(N’-trimethylsilyl)ethane-1-amino-2-amido), was employed as the metal precursor for the first time. The Co-N coordination provides an optimal reactive site for a variety of organic linker groups, as demonstrated here by three organic precursors that share the same rigid benzene backbone but differ in reactive groups: 1,4-benzenediol (hydroquinone; HQ), 1,4-benzenedithiol (BDT), and 1,4-benzenedicarboxylic acid (terephthalic acid; BDC). A comprehensive set of characterization techniques, combined with first principles density functional theory (DFT) calculations, is used to systematically investigate the three new ALD/MLD processes and the stability of the resulting Co(II)-organic thin films: Co-HQ, Co-BDT, and Co-BDC. The reactivity and stability trends of the organics are found as BDC>HQ>BDT and BDC>>BDT>>HQ, respectively. Decomposition mechanisms are provided for Co-HQ and Co-BDT. Furthermore, the preparation of low-density, porous CoO thin films with tunable structural and optical properties, difficult to achieve otherwise, is demonstrated via calcination in N2 of the Co-BDC thin films.