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Enhancing Utilization of Municipal Solid Waste Bottom Ash by the Stabilization of Heavy Metals
No full textWaste-to-energy (WtE) is a key part of modern waste management. In the European Union, approximately 500 WtE plants process more than 100 million tons of waste yearly, while globally, more than 2700 plants handle over 500 million tons. Roughly 20% of the waste processed is bottom ash (BA). However, this ash can contain heavy metals in concentrations that may render it hazardous. This paper presents a study focusing on stabilizing municipal solid waste incineration BA using simple and industrially viable treatments. The Slovenian WtE plant operator wishes to install the stabilization process; thus, the samples obtained from the plant were treated (1) with a CO2 gas flow, (2) with water spraying, and (3) with a combination of water spraying and a CO2 gas flow under laboratory conditions. Thermodynamic calculations were applied to define potential reactions during the treatment processes in the temperature range from 0 to 100 °C and to define the equilibrium composition of the treated ash with additions of CO2 and water. The standard leaching test EN 12457-4 of treated ash shows a reduction of over 40% in barium concentration and over 30% in lead concentration in leachates
Comparative experimental and DFT study of the electrochemical oxidation of azo pyridone dyes
No full textThis study examines electrooxidation behavior of three aryl azo pyridone using cyclic (CV) and square-wave voltammetry (SWV) on a glassy carbon electrode (GC) in Britton–Robinson (BR) aqueous buffer solutions and quantum-chemical calculations. Results indicate that the electrochemical activity is closely related to the presence of the hydrazone (–NH–N=) bridge of the dyes. The most stable protonated and deprotonated forms of dyes are identified by comparing experimental UV–Vis spectra with calculated spectra. Additionally, calculated ionization energies for both forms aligned with observed electrochemical activity, emphasizing the deprotonatedanionic form as the most active. The proposed electrooxidation mechanism suggests that initial step involves dye deprotonation to achieve the most stable anionic form, followed by electron removal to generate a radical, and subsequent geometric adjustments to optimize electron density distribution and stability. The differences of the electrochemical behavior of dyes are discussed with consideration of underlying mechanism
Biodegradable Electrospun PLGA Nanofibers-Encapsulated Trichinella Spiralis Antigens Protect from Relapsing Experimental Autoimmune Encephalomyelitis and Related Gut Microbiota Dysbiosis
No full textPurpose: Trichinella spiralis has evolved complex immunomodulatory mechanisms mediated by excretory-secretory products (ESL1) that enable its survival in the host. Consequently, ESL1 antigens display excellent potential for treating autoimmune diseases such as multiple sclerosis (MS). However, whether timely controlled delivery of ESL1 antigens in vivo, as in natural infections, could enhance its therapeutic potential for MS is still unknown. Methods: To test this, we encapsulated ESL1 antigens into biodegradable poly (lactide-co-glycolic) acid (PLGA) nanofibers by emulsion electrospinning as a delivery system and assessed their release dynamics in vitro, and in an animal MS model, experimental autoimmune encephalomyelitis (EAE), induced 7 days after PLGA/ESL1 subcutaneous implantation. PLGA/ESL1 effects on EAE symptoms were monitored along with multiple immune cell subsets in target organs at the peak and recovery of EAE. Gut barrier function and microbiota composition were analyzed using qPCR, 16S rRNA sequencing, and metabolomic analyses. Results: ESL1 antigens, released from PLGA and drained via myeloid antigen-presenting cells through lymph nodes, protected the animals from developing EAE symptoms. These effects correlated with reduced activation of myeloid cells, increased IL-10 expression, and reduced accumulation of proinflammatory natural killer (NK) cells, T helper (Th)1 and Th17 cells in the spleen and central nervous system (CNS). Additionally, CD4+CD25hiFoxP3+ regulatory T cells and IL-10-producing B cells were expanded in PLGA/ESL1-treated animals, compared to control animals. The migration of ESL1 to the guts correlated with locally reduced inflammation and gut barrier damage. Additionally, PLGA/ESL1-treated animals displayed an unaltered microbiota characterized only by a more pronounced protective mevalonate pathway and expanded short-chain fatty acid-producing bacteria, which are known to suppress inflammation. Conclusion: The delivery of T. spiralis ESL1 antigens via biodegradable electrospun PLGA nanofiber implants efficiently protected the animals from developing EAE by inducing a beneficial immune response in the spleen, gut, and CNS. This platform provides excellent grounds for further development of novel MS therapies
An Analysis of Transition Temperature for Real and Simulated Heat Affected Zone of HSLA Steel
No full textThe aim of this paper is to present the analysis of the influence of different test temperatures on the impact toughness of the real heat affected zone (RHAZ) and the simulated heat affected zone of the welded joint (SHAZ) of high strength low-alloy steel. Through thermal cycle simulation, which includes heating to a certain temperature and programmed cooling, the microstructure of different areas of the heat-affected zone was obtained on the samples, which allows us to directly draw appropriate conclusions regarding the real heat-affected zone of the welded joint. Based on the previous text, a comparison of the brittleness transition temperature values for RHAZ and SHAZ as a very important factor for structural steels was made. It has been observed that with a decrease in temperature many metals exhibit a sudden decrease in toughness, so the temperature at which the material transits from ductile to brittle fracture is called brittle transition temperature (ductile-brittle transition temperature). This indicator is very important regarding further design and exploitation of welded steel structures
The importance of training and education in developing competent welding coordinators
No full textThe ever growing requirement for skilled welding coordinators has risen alongside advancements in
welding technologies and quality standards across various industries. International welding society has
implemented the IIW Guideline IAB-252r5-19/SV-02 that provides a structured approach for the training and
qualification of welding coordination personnel, emphasizing the importance of education in shaping competent
professionals. This paper emphasizes the importance, role and structure of education and training in ensuring
compliance with technical standards, fostering safety and quality, and addressing the challenges of modern
industrial practices
High-Performance Cathodes for Alkaline Water Electrolysis in a Zero-Gap Setting: Ni-Sn/Ni Foam Prepared by Galvanostatic Electrodeposition
No full textIn an attempt to obtain fully functional cathode materials for zero-gap alkaline water electrolysis, Ni foam substrates with various pore diameters were modified through galvanostatic electrodeposition of Ni-Sn alloys as an easily scalable procedure. To optimize the production process for each substrate, Ni-Sn alloys were electrodeposited at five different constant current densities. The obtained cathodes were primarily subjected to hydrogen evolution in 1 M KOH to evaluate their activity, while the best-performing samples were further investigated in 30 wt % KOH at 70 °C in a three- and two-electrode arrangement. Detailed electrochemical impedance spectroscopy analysis of hydrogen evolution reaction (HER) conducted with a three electrode arrangement indicated two semicircles on the Nyquist plots that confirmed that the adsorption of intermediate (Hads) is potential dependent. Relevant HER parameters such as exchange current density and relaxation time showed exceptional performance of optimized electrodes. During zero-gap single cell tests with bare Ni foam used as the anode, onset voltages for Ni-Sn cathodes were around 1.64 V (for bare foams, 1.99 V), with cell voltage at 1 A cm-2 being as low as 2.03 V (for bare foams, 2.57 V). The cathodes were also subjected to a long-term stability test, showing excellent activity preservation. Great stability, low cell voltage, and low production cost confirm their suitability for industrial applications. Top-view as well as cross-section electron microscopy analysis have shown that the entire foam surface was evenly covered with Ni-Sn coating. The composition of the investigated coatings was within the range of Ni(1+x)Sn (0 < x < 0.5) metastable phase and practically independent of deposition current density. Aberration-corrected scanning transmission electron microscopy revealed that the so-called metastable phase is in fact the Ni3Sn2 phase, which is shown for the first time for electrodeposited Ni-Sn alloys
New methods in the process industry
No full textWe are happy to introduce a new special topic with the aim of introducing new methods and procedures for optimizing industrial processes. These works highlight the industry's ongoing commitment to sustainability, efficiency, and environmental responsibility.
These contributions underscore the transformative potential of innovative methodologies in the process industry. By leveraging waste materials, advancing green chemistry, and optimizing water treatment processes, the research presented on this special topic sets a benchmark for sustainable industrial practices. We look forward to practically implementing these findings, driving progress in environmental stewardship and industrial efficiency
Rubisco protein from agricultural waste with enhanced solubility for complexation with gum arabic
No full textAgricultural waste holds significant potential as a source of nutritionally valuable components
but remains largely underutilized. Oilseed crop leaves, in particular, are rich in proteins, with
the enzyme RuBisCO comprising a major portion of the protein fraction. However, RuBisCO
extracted using standard methods often exhibits limited solubility, which can hinder its
interaction with other polymers in various applications. This study aimed to extract RuBisCO
from pumpkin leaves using a combination of isolation techniques—salting out with ammonium
sulfate followed by three cycles of acidic precipitation. The extracted protein was further
characterized using the Kjeldahl method, FTIR spectroscopy, and isoelectric point determination.
Results showed a protein purity of over 90%, with the FTIR spectrum confirming the presence of
characteristic peptide bands and a small amount of residual ammonium sulfate. The extracted
protein demonstrated improved solubility compared to fractions obtained using individual
methods, with a relatively high isoelectric point of approximately 5.39. The obtained protein was
then used to form complexes with gum arabic, an acidic polysaccharide. Various protein-topolysaccharide
ratios were tested (1:2, 1:1, 2:1, 3:1, 5:1, and 10:1) as the ratio is one of the most
important parameters affecting complex formation by modifying the charge balance in the
complexes. Complex formation was monitored by changes in ζ-potential across different pH
levels (8.5 to 2.0), with the highest yield occurring at the isoelectric point of the proteinpolysaccharide
mixture. The isoelectric points for all tested ratios were determined, showing a
neutral ζ-potential between 2.95 and 4.39. Higher gum arabic content resulted in a lower
isoelectric point; however, the values remained within an acceptable range, ensuring the
complexes' suitability as carriers for vitamins or other sensitive compounds.In conclusion, the
successful extraction and enhanced solubility of RuBisCO from pumpkin leaves, combined with
the formation of protein-polysaccharide complexes, demonstrates the potential of agricultural
waste as a valuable source of functional biomaterials for various applications
Biosynthesis of Silver Nanoparticles on Polypropylene Nonwovens: towards Antimicrobial Protection
No full textThe utilization of disposable face masks is an essential approach to mitigate the transmission of microorganisms. Composed mainly of polypropylene (PP) nonwoven material, these masks do not exhibit any antimicrobial properties. This study examines the feasibility of employing Ag-based nanoparticles (NPs) as an antimicrobial agent. To activate the chemically inert PP samples, corona discharge was applied at atmospheric pressure. Subsequently, a sol-gel coating with (3-aminopropyl) triethoxysilane was performed, which introduced amino groups necessary for the absorption of silver ions. The in situ biosynthesis of Ag-based NPs was conducted using extracts from Cannabis sativa L., Cannabaceae, and Paliurus spina-christi Mill., Rhamnaceae. Morphological and chemical changes were evaluated using FESEM, FTIR, and XPS analyses. The antimicrobial activity of the fabricated substrates was tested against the Gram-negative bacterium Escherichia coli, the Gram-positive bacterium Staphylococcus aureus, and the yeast Candida albicans. Cytotoxicity assessments were conducted utilizing HaCaT and MRC5 cell lines. Findings from FESEM and AAS revealed that the size and quantity of the synthesized NPs were influenced by the plant extract used. XPS analysis confirmed the presence of NPs as a mixture of Ag2O and AgO, which achieved a remarkable bacterial reduction of 99.9% without exhibiting cytotoxic effects
