16168 research outputs found
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Optimized TiO2 coatings on AISI 316 steel for advanced photocatalytic wastewater treatment: mechanism and performance /
No full textThe development of robust and efficient photocatalysts is essential for sustainable wastewater treatment. This study evaluates the photocatalytic degradation of ciprofloxacin (CIP) using three TiO2-coated systems: TiO2 nanotube arrays (TiO2 NTA), Bare-Coated TiO2, and Methanol-Enhanced TiO2, with a focus on coating uniformity, interfacial stability, and reaction pathways. Surface morphology analysis (SEM) revealed that TiO2 NTA exhibited a uniform surface, optimizing active site exposure and photocatalytic efficiency. Methanol-Enhanced TiO2 formed a refined crack pattern, enhancing coating stability and facilitating uniform distribution of TiO2 particles, while Bare-Coated TiO2 showed a highly fractured surface, limiting its catalytic efficiency. X-ray diffraction (XRD) confirmed that the anatase phase was the dominant crystalline structure across all coatings, ensuring photocatalytic activity. High-performance liquid chromatography–mass spectrometry (HPLC-MS) analysis revealed distinct degradation patterns, with TiO2 NTA facilitating rapid fragmentation of CIP into multiple low m/z intermediates, indicating aggressive oxidative breakdown. Methanol-Enhanced TiO2 exhibited a more controlled degradation pathway, with prominent peaks at 316 (+) m/z and 285 (+) m/z, suggesting selective oxidation and gradual mineralization rather than immediate fragmentation. The degradation mechanism of Methanol-Enhanced TiO2 likely favored sustained transformation steps, potentially reducing the accumulation of harmful byproducts. Under ultraviolet (UV)-driven photocatalysis, Methanol-Enhanced TiO2 outperformed Bare-Coated TiO2, achieving accelerated degradation kinetics, while TiO2 NTA maintained high stability but lagged in mineralization efficiency. The introduction of ozone further enhanced degradation, ensuring complete CIP removal across all systems. Methanol-Enhanced TiO2 maintained a degradation efficiency of 88.72% after five reuse cycles, closely matching the 88.75% TiO2 NTA, demonstrating strong reusability and potential for scalable wastewater treatment applications in photocatalytic treatment reactors. These findings underscore the importance of coating methodologies and interfacial properties in optimizing TiO2-based photocatalysts, positioning Methanol-Enhanced TiO2 as a viable and durable alternative to TiO2 NTA for sustainable micropollutant removal
Mechanical and microstructural properties of alkali-activated biomass fly ash and diatomite blends /
No full textBiomass is one of the most important sources of renewable energy, generating large amounts of ash. This increases the amount of waste, landfill, and air pollution. This work focuses on the sustainable disposal of this ash by producing an innovative binder. The mechanical and microstructural properties of alkali-activated biomass fly ash (BFA) and diatomite (DT) mixtures are currently insufficiently studied. New scientific knowledge of these properties is needed. This study presents the possibility of using BFA and diatomite as aluminosilicate precursors for the production of an alkaline-activated binder. It was found that the reactivity of BFA is relatively low. Based on XRD analysis, the mineral composition of BFA is dominated by quartz and calcite, both of which are non-reactive minerals. Therefore, mixtures with DT were created as precursors. According to Rietveld analysis data, an amorphous part was found in both precursor materials, BFA and DT. Comparing the chemical composition of BFA and DT using XRF and Rietveld analysis data, it was found that the amorphous part of BFA consists of CaO, while the amorphous part of DT consists of SiO2. Thus, the combination of these precursors should complement each other during the geopolymerisation process. After 28 days of curing, the strength of the binders was dependent on the amount of DT, and the highest strength values, such as 16.4 MPa and 15.3 MPa, were obtained when DT contents were 10% and 30%, respectively. After geopolymerisation, XRD analysis showed that calcium silicate hydrate, hydrotalcite, and calcium aluminium silicate hydrate (zeolite A type) were formed. SEM analysis confirmed the XRD results and showed that DT additives (10% and 30% by weight) improved the microstructure of alkali-activated BFA, which is closely related to compressive strength values. The proposed binder will be useful in the preparation of concrete, which could be used for artificial aggregates or small architectural elements
Bendradarbiavimu grindžiamas požiūris į veiklos valdymą: atsakas į sudėtingus iššūkius.
No full textComplexity is a significant challenge for public organizations’ management systems. Based on an extensive literature review, an on-line survey of Lithuanian public servants in strategic management positions, and statistical modelling, this exploratory survey aims to assess whether a performance management system that embraces mechanisms for collaboration affects an organization’s capacity to deal with complex policy problems. We suggest that mechanisms for collaboration – namely, collaborative policy dialogues, reflexive performance measurement, and joint learning forums – enable organizations to better understand complex policy problems, detect emergencies, and develop innovative solutions to address them. The study found that based on the views of experts an organization’s capacity to deal with complex policy problems increased when mechanisms for collaboration are governed by its performance management system
Pokyčių skatinimas: Europos Sąjungos civilinių misijų analizė pokyčių teorijos požiūriu.
No full textThis paper examines the implementation process of European Union (EU) civilian Common Security and Defence Policy (CSDP) Missions using the Theory of Change framework, focusing on resources, outputs, and impact. The research employs a qualitative methodology, drawing on empirical data from indepth interviews, conducted in December 2024, with purposively selected European External Action Service (EEAS), Member state representatives, CSDP Missions management representatives, directly involved in the planning and execution of CSDP missions. Despite the limitations of this study, such as only partial coverage of EU missions due to the sensitivity of the topic and limited access to information, it provides valuable insights into the process of mission implementation and the challenges that influence their outputs and impact. Based on interviews with selected experts, the study identifies strategic incoherence, limited expertise and fragmented coordination efforts as key obstacles, especially in advancing digital transformation. Although short-term outputs are visible, long-term technological progress is hampered by systemic inertia and institutional limitations
3D printed parts exhibit superior elastic properties to milled ones /
No full textWhile many studies on fused filament fabrication (FFF)-printed polymers focus on ultimate tensile strength or failure analysis, the elastic region of the stress–strain curve is frequently overlooked. However, in most engineering applications, components operate well within the elastic range. In mechanical joints, support frames, and other load-bearing structures, stiffness and elastic response are more critical than post-failure behavior, as these properties determine system performance during standard operating conditions before any damage occurs. This study examines the elastic properties of acrylonitrile butadiene styrene (ABS) components fabricated via FFF, with a focus on the impact of printing orientation and nozzle temperature. Tensile tests were performed according to ISO 527-2:1993, and the results were compared to those of milled ABS parts (referred to as FT). Two print orientations were studied: XT, where the layers are oriented perpendicular to the loading direction, and ZT, where the layers are aligned parallel to the loading direction (load-aligned). The study reveals that printing orientation has a significant impact on mechanical behavior. The specimens printed in the ZT orientation exhibited superior elastic modulus and tensile strength compared to the XT specimens and also outperformed the milled FT parts. At 245 °C, the ZT specimens achieved an average tensile strength of 41.0 MPa, substantially higher than the FT’s 31.1 MPa. Moreover, the ZT had approximately 12.6% higher elastic moduli than the FT (1.97 GPa ZT compared to 1.74 GPa FT). Although the FT parts showed higher strain at break, the ZT-printed parts demonstrated a stiffness and strength that suggest their viability as replacements for machined components in load-bearing applications
Health benefits of ethnic fermented foods /
No full textUNLABELLED: Food science and technology have evolved to enhance food availability, nutrition, safety, and marketability, addressing global challenges such as hunger and malnutrition. However, projections indicate that by 2030, over 670 million people may face hunger, emphasizing the need for innovative and sustainable solutions. Ethnic fermented foods (EFF) originate from the heritage and culture of various ethnic groups who utilize their ethnomicrobiological knowledge of fermentation with local plant- or animal-based ingredients. EFF provide a promising approach to promote a healthier, sustainable, and more inclusive global food system. They are also traditionally produced by combining local ingredients with artisanal practices. However, urbanization and changes in eating habits threaten the preservation of EFF and the associated native microorganisms that are essential for their production. This research systematically examines health-related endpoints reported in human clinical studies of EFF. While some EFF such as natto, kimchi, and tempeh, originating from Asia have gained global recognition and consumption, multiple others remain unknown and understudied. This comprehensive narrative review aims to identify the potential health benefits associated with these foods. A systematic search in PubMed, Scopus, and the Cochrane Library Central initially resulted in 3,488 entries, which were narrowed down to 125 reports fulfilling the selection criteria defined to identify human studies investigating the functionality of EFF. CADIMA software was used to manage and select references. Data synthesis focused on clinical indications, offering valuable insights into health benefits of EFF, such as gut health, immune modulation, metabolic benefit, cognitive function, cardiovascular, bone, oral, eye, skin health and antimicrobial effect. This systematic narrative review highlights the importance of EFF in improving health, emphasizing their role in sustainable food systems, and underscoring the importance of preserving traditional practices.
SYSTEMATIC REVIEW REGISTRATION: https://osf.io/hnksr/
Challenges and limitations in recycling of post-consumer cotton denim waste into new textiles /
No full textThis study investigates the feasibility of recycling post-consumer cotton denim waste into new yarns by examining the effects of recycled fibers percentage, twist level, and spinning methods (ring vs. rotor) on the yarn and fabric quality. Recycled cotton fibers, blended with chemically recycled polyester in 3 different ratios, and 12 samples were developed, which then knitted into single jersey fabrics. Fiber yield and waste generation during the yarn production were critically monitored to check the effectiveness of recycling process. Results indicate that increasing recycled content by more than 10% significantly degrades the yarn strength, elongation, and fabric durability due to the fiber shortening from prior use. Mechanical recycling yielded only 45–50% usable fiber, with higher waste percentages in yarn production leading to greater processing losses. The resulting developed knitted fabrics exhibited poor pilling resistance (Grade 1) compared to virgin cotton blends (Grade 4). Statistical analysis confirmed that the percentage of recycled fibers critically impacts yarn tenacity and breaking force. Post-consumer textile recycling holds promise for circular fashion, but current mechanical methods face limitations in producing high-quality yarns. This research raises important questions about the feasibility of large-scale post-consumer textile recycling in achieving sustainability goals while maintaining quality of final product
Opoka as a natural material for phosphorus removal: properties and applications /
No full textThis study investigates the adsorption efficiency of thermally activated natural opoka, a siliceous–calcareous sedimentary rock, as a low-cost adsorbent for removing phosphorus from aqueous solutions. Comprehensive characterization using XRF, XRD, and STA revealed that raw opoka is primarily composed of quartz, tridymite, and calcite, with a CaO/SiO2 molar ratio of approximately 0.45. After calcination at 850 °C, calcite decomposes and reacts with silica to form wollastonite, enhancing surface reactivity. Adsorption experiments conducted at phosphorus concentrations of 0.2, 2.6, and 5.0 g of P/L demonstrated that the material’s removal efficiency for phosphorus was highest at low concentrations (25.7% at 0.2 g/L) and decreased with an increase in concentration (20.8% at 2.6 g/L and 18.6% at 5.0 g/L). The adsorption process followed pseudo-second-order kinetics (R2 > 0.999), indicating that chemisorption is the dominant mechanism. It is assumed that amorphous calcium phosphate forms at low phosphorus concentrations and an alkaline pH, whereas brushite is more prevalent at higher concentrations under acidic conditions. Potassium adsorption was negligible and reversible in all cases. The findings demonstrate that calcined opoka has promising applications as a reactive calcium silicate material for sustainable phosphorus management in decentralized water treatment systems
Optimisation of pressurised liquid extraction and subsequent hydrolysate fermentation by lactiplantibacillus plantarum for integrated bioprocessing of Ulva sp /
No full textUlva sp. is a fast-growing, widely distributed marine alga with significant potential across various sectors, yet it remains underutilised. This study optimised pressurised liquid extraction (PLE) to obtain high-value fractions from Ulva biomass. Using a Box-Behnken design and response surface methodology, the effects of sulfuric acid concentration, temperature, and extraction time on yield, reducing sugars, total carbohydrates, and phenolic content were evaluated. Optimal conditions were identified as 110 °C, three 15 min cycles, and 3.6% sulfuric acid. Under these parameters, the extract yielded 46.9 g/100 g dry weight (DW), with 244.0 mg of reducing sugars/g DW, and 15.4 mg GAE/g DW, aligning with model predictions. The hydrolysate supported fermentation by Lactiplantibacillus plantarum, resulting in a growth of ~9 log CFU and the production of 3.3 g/L of lactic acid within 48 h. The antioxidant capacity remained stable post-fermentation, with CUPRAC, DPPH, and ABTS values of ~52, 38, and 18 mg TE/g DW, respectively. This work demonstrates the effectiveness of PLE in extracting valuable compounds and the feasibility of microbial fermentation of the extracts. This integrated approach highlights the potential of Ulva biomass and offers a platform for further applications in food, cosmetics, and nutraceuticals
Unpacking competitive performance in 5* hotels: the joint effect of dynamic managerial capabilities and digital transformation /
No full textDigital transformation in the hospitality sector was accelerated by the COVID-19 pandemic. Strategy scholars discussed dynamic managerial capabilities as capabilities needed to adapt to rapid change and navigate digital transformation to gain a competitive advantage in the hospitality sector. It suggests that by leveraging digital technologies, fostering a culture of innovation, and building agile business ecosystems, hospitality organizations can enhance their competitive position and ensure long-term sustainability in an increasingly digitalized marketplace. The research question of our study is how dynamic managerial capabilities and the adoption of digital technologies affect the competitive advantage of the hospitality sector. We address the research question by deploying a multiple case study research design and collecting data from 5* Hotels in Lithuania. The study finds that the synergy between dynamic managerial capabilities such as data-driven decision-making, connectivity to internal and external networks, also digitally driven operational efficiency, and sustainability-oriented attitudes significantly enhances the competitive performance of 5-star hotels by fostering innovation, strategic alignment, and superior guest value. We also provide insights for 5* hotel owners and managers