16168 research outputs found
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Hydrothermally treated cement bypass dust as supplementary cementitious material /
No full textAbstract: In this study, the possibility of using cement bypass dust as a cement additive was investigated. Utilization of cement bypass dust remains a major problem in cement production, as huge amounts of it are stored in landfills. In the work presented, a hydrothermal treatment is proposed to modify the properties of these dusts and to expand their use. Hydrothermal treatment with pure bypass dust and quartz was carried out to achieve a CaO/SiO2 ratio of 1 to 2. The samples were synthesized at 200 ° C 2, 4, 8 and 24 h. To examine the influence on cement properties, the sample was selected with the CaO/ SiO2 ratio 1, hydrothermally treated 8 h. This study employed the following research approaches: XRD, XRF, DSC-TG and isothermal calorimetry. Most of the target synthesis products, tobermorite and calcium silicate hydrates, form after 8 hours of sample synthesis in which quartz was added to bypass dust and a CaO/SiO2 ratio of 1 was achieved. Examination of the composition of the liquid medium following hydrothermal processing shows that almost all chlorine passes into the liquid medium, while K2O remains partially in the solid synthesis product. The synthesised additive is an effective catalysator for the hydration reactions of Portland cement. After a 28-day curing period, specimens incorporating up to 10% replacement of Portland cement by weight with modified bypass dust demonstrate compressive strengths comparable to, or surpassing, those of specimens composed exclusively of Portland cement
Enhancing the nutritional value of foods through probiotics and dietary fiber from fruit and berry pomace /
No full textThe growing demand for health-promoting food products has led to increased efforts to develop formulations enriched with probiotics and dietary fiber (DF). While traditional fermented foods remain widely recognized sources of probiotics, there is a pressing need to innovate novel, nutritious, and high-quality alternatives that also incorporate additional functional ingredients. In the context of sustainable consumption and health-conscious dietary trends, fruit and berry pomace has emerged as a promising source of DF with prebiotic potential, supporting the growth and activity of beneficial gut microorganisms. A growing body of research emphasizes the potential of pomace valorization, showcasing its relevance in the development of value-added food products. This review explores the key features and selection principles for probiotic strains, particularly those from the former group of Lactobacillus species, alongside opportunities for combining probiotics with fruit and berry pomace in functional food matrices. Special attention is given to the physiological and technological attributes of DF derived from pomace, which are critical for their successful application in food systems and their potential synergistic effects with probiotics. Although numerous probiotic-enriched products are currently available, DF remains an underutilized component in many of these formulations. Research has predominantly focused on dairy-based applications; however, the increasing demand for plant-based diets calls for a shift towards non-dairy alternatives. Looking forward, future innovations should prioritize the integration of probiotics and pomace-derived DF as symbiotic systems into plant-based food products, with an emphasis on their dual roles as nutritional enhancers and potential prebiotics
The possibilities of using non-traditional raw materials for fertilizing products /
No full textIn recent years, the Green Deal has become a cornerstone of the European Union’s development strategy, aiming to establish a sustainable, innovative and environmentally friendly economy. One of its primary goals is to reduce the negative impact of intensive farming by promoting sustainable agricultural practices. These practices include replacing synthetic fertilizers with more natural alternatives and substituting chemical plant protection products with biological solutions. A noteworthy prospect in this context is the growing insect farming industry, which opens up new possibilities for the food industry via waste processing. In Lithuania, insect farming is also expanding rapidly, with companies producing several hundred tons of frass (insect excrement and residues from growing media) every year. As insect farming is projected to increase rapidly over the next decade, the amount of frass produced will also increase. Therefore, it is necessary to find sustainable ways to use this byproduct. Frass is emerging as an important area of research and practical innovation with great potential for fertilizer production. Initial studies show that frass can contain up to 6% nitrogen, 2% phosphorus and 3% potassium, making it a valuable alternative to synthetic fertilizers. The chitin content (nearly 14%) in frass not only improves the soil but also improves plant resistance to disease. In addition, its organic composition improves soil structure and microbiological activity, contributing in the long term to increasing soil fertility. This paper analyses different samples of frass, assesses their physical and chemical properties and discusses the possible applications of these products in the context of sustainable agriculture. The studies show that frass can be a valuable raw material for fertilizer production, potentially reducing the need for synthetic fertilizers and contributing to the reduction in agricultural waste. By combining economic benefits with ecological sustainability, this research contributes to wider sustainable agricultural innovation
Image analysis methods for assessing fibrous microplastic release /
No full textFibrous microplastics can be released into the environment through fiber breakage due to various factors. Analysis using light microscopes and digital cameras is among the most popular methods for studying fibrous microplastics due to its accessibility. However, manually processing images and assessing fibrous microplastics is highly time-consuming. This study compares different analytical image analysis methods to find the most suitable option for effective fibrous microplastics assessment. To analyze the fibrous microplastics, three types of image analysis methods were applied: manual analysis with ImageJ, semi-automatic analysis with ImageJ’s Analyze Particles plugin, and automatic analysis using AI-based Ilastik software. For the evaluation, a black knitted fabric was used with the following specifications: composition – 95% polyester / 5% elastane; mass per unit area – 224.0 g/m2; thickness – 0.52 mm; course density – 23.0±0.5 cm−1; wale density – 22.0 ± 0.5 cm−1. Three specimens were prepared. Individual washing tests were performed on each specimen. Wastewater was filtrated through filters after each wash. Each filter was photographed using light microscope (Lumenera Infinity) and digital camera (Nikon D5600) with lens (AF-P NIKKOR 18-55mm f/3.5- 5.6G). Results indicated that manual, semi-automatic and automatic methods were similarly effective in assessing non-overlapping microplastics. Images taken with the light microscope provided more accurate results. After training the AI-based software, the automatic method was the least time consuming and manual analysis took the longest. However, neither semi-automatic nor automatic methods were performing effectively on overlapping fibrous microplastics and manual corrections were required to attain more accurate results. These findings suggest that AI-based automatic software can be the most effective and the least time-consuming solution for analyzing fibrous microplastics when they are wellseparated on surfaces, but it needs further development to improve the analysis for overlapping fibrous microplastics
Sustainable alternative of palm wine analogue from different tiger nut milk-sugar syrup blends for local production /
No full textAim: The unfermented pale-yellow exudates (“palm sap”) emerge from tapped unopened spathe of mostly oil palm (Elaeis guineensis) and raphia palm (Raphia hookeri). Besides, tiger nut milk (Kunuaya) is among the non-alcoholic refreshing drinks with dairy appearance. A sustainable alternative could therefore emerge from blends of tiger nut milk and sugar syrup to serve a resembling role as palm wine. In this context, therefore, palm wine analogue from different tiger nut milk and sugar syrup blends using palm wine dreg as inoculum was evaluated by proximate, physicochemical, microbial, and sensorial analyses at different time intervals. Methods: The materials were processed, analyzed, and packed using standard referenced procedures. This required freshly tapped palm sap juxtaposed with blends of tiger nut milk-sugar syrup beverage, and thereafter subjected to aerobic fermentation. Importantly, the tiger nut milk-sugar syrup medium has been pitched with palm wine dreg (inoculum source) between fermentation time 26–30 h, and temperature 29.8°–32°C. Results: Considering all the analytical outcomes, from proximate, microbiological, physicochemical, to sensory data, the control appeared to somewhat resemble those of the experimental samples of this study. Conclusions: Potentially, the (palm wine) analogue produced from tiger nut milk and sugar syrup blends using (palm wine) dreg as inoculum could be embraced by the market as natural palm wine. Indeed, the emergent product should serve as an alternative sustainable promise for palm wine, which could help fill the market supply gap, especially in the seasons of reduced supply/yield
Predviđanje i usporedba mehaničkih svojstava modela drvnih konstrukcija.
No full textIn this study, different methods were used to compare the mechanical properties of spruce wood. The aim was to evaluate the potential of predicting the properties and behavior of wooden structural elements containing holes and voids. The modulus of elasticity (MOE) was determined using three methods: the static 4-point bending method according to the standard EN 408:2010+A1:2012, the original dynamic transverse resonance vibration method, and the ANSYS design program. The research was carried out in two phases. In the first phase, the dynamic modulus of elasticity (MOEd) of the samples was determined without causing them any damage. In the second phase, the bending resistance and static modulus of elasticity (MOE) of the same samples were determined. Using the ANSYS program and considering the dynamic modulus of elasticity, density, and other parameters, the bending resistance and static modulus of elasticity (MOEa) were predicted. During the first stage of the study, the modulus of elasticity (MOE) was measured for different groups of samples using different methods. The results showed that the average values of MOE differed by up to 4.6 % between the different groups. In the second stage, additional samples were divided into 5 groups, and holes or voids were formed in them according to 5 different schemes. The MOE, bending resistance, MOEa, and bending resistance were determined for each group, and it was found that the average MOE values differed by up to 17 % between the different groups. The presence of holes and voids in the wood increased the anisotropy of the material, which had the most significant impact on the results. Regardless of the number of holes and voids, the damping factor increased by up to 2.1 times
Energy management of smart buildings during crises and digital twins as an optimisation tool for sustainable urban environment /
No full textThe COVID-19 pandemic underscored the need for resilient energy management systems in smart buildings, especially during crises. This study investigates the role of Digital Twins in optimising energy systems, analysing energy use in a residential complex in Cyprus under lockdown conditions. Advanced predictive models, including Skforecast, XGBoost, LightGBM, CatBoost, LSTM, and RNN, were employed to forecast energy demand. While gradient boosting models performed well, LSTM showed superior accuracy in capturing long-term patterns. These models are crucial for anticipating energy demand fluctuations, especially during unforeseen events such as the COVID-19 pandemic. The use of Digital Twins enabled real-time monitoring, proactive maintenance, and decision-making, significantly improving energy efficiency and resilience. This research underscores the importance of interdisciplinary collaboration and the integration of advanced technologies in building management. The findings advocate for a holistic, human-centric approach to energy management that prioritises adaptability, resilience, and sustainability in the face of ongoing and future challenges
Naujų organinių medžiagų, skirtų jutikliams ir elektroluminescenciniams prietaisams, intramolekulinės ir tarpmolekulinės krūvio pernašos emisijos reguliavimas.
No full textIn this PhD dissertation, the tuning of intramolecular and intermolecular charge transfer emissions in novel organic materials is examined, with a focus on their potential applications in electroluminescent devices and sensing. The study investigates the optoelectronic, photophysical, and electrochemical characteristics of substances displaying thermally activated delayed fluorescence (TADF). A major field of interest is how organic semiconductors react to outside stimuli such as temperature and UV radiation, which affects their emissive behaviour, molecules conformation, and morphology. The study highlights the significance of novel phenomena for optoelectronic applications, such as thermally controlled mechanochromic luminescence and photostimulated fluorescence. A number of recently created organic compounds are examined for their structural and functional characteristics. The study offers significant insights into material design by exposing charge transfer pathways and their role in improving emission efficiency. The knowledge of organic semiconductors and their promise for high-performance, sustainable devices like OLEDs and UV sensors is greatly expanded by this work. It lays the groundwork for the creation of next-generation materials for optoelectronic devices by revealing how external stimuli can be used to control molecular characteristics
Characterization of the municipal plastic and multilayer packaging waste in three cities of the Baltic States /
No full textThe composition of plastic and multilayer packaging waste was assessed in the mixed municipal solid waste (MSW) streams of the Kaunas (Lithuania), Daugavpils (Latvia) and Tallinn (Estonia) municipalities. For the analysis of samples in the mixed MSW streams, the authors used manual sorting and a visual recognition method. Composition analysis of plastic and multilayer packaging waste from separately collected waste of multi-family and single-family households was performed in the Kaunas and Tallinn municipalities. For the analysis of samples in the separately collected waste streams, the research group combined manual sorting and near-infrared (NIR) spectroscopy methods. The findings reveal that the percentage distribution of plastic and multilayer packaging waste within the municipal solid waste (MSW) stream is relatively consistent across the municipalities of Kaunas, Daugavpils and Tallinn, comprising 40.16%, 36.83% and 35.09%, respectively. However, a notable variation emerges when examining separately collected plastic and multilayer packaging waste streams. In this category, the proportion of plastic and multilayer packaging within the total separately collected packaging waste stream ranges from 62.05% to 74.7% for multi-family residential buildings and from 44.66% to 56.89% for single-family residential buildings. The authors provided further insights for the enhanced recycling potential of different plastic materials through improved sorting
Thermal comfort and adaptive occupant behaviour in open plan offices in India and Lithuania /
No full textUnderstanding the relationship between thermal comfort and adaptive behaviour in office environments is important for designing sustainable and occupant-centric buildings. This study investigates the thermal sensation, comfort preferences, and adaptive behaviours of occupants in five Indian and two Lithuanian offices. Indoor environmental parameters were measured, and online thermal comfort surveys were carried out. In total, 274 responses were collected. Differences between the two countries were observed in perception of the indoor thermal environment, comfort preferences, and adaptive behaviours. In the Indian offices, despite experiencing higher temperatures and relative humidity, most occupants reported feeling thermally neutral or slightly cool. In the Lithuanian offices (measured in the heating season), a third of the occupants felt slightly cool and another third slightly warm. Occupants in the Indian offices (limited direct access to temperature control, greater prevalence of business attire) showed a higher preference for adjusting the temperature. The occupants in the Lithuanian offices (access to temperature control, more flexible attire) preferred more frequently to adjust their clothing. Consumption of warm or cold beverages for thermal adaptation was equally preferred in the two countries. About 86% of the occupants who did not choose any adaptations reported being comfortable, compared to 65% of those who did. These findings highlight the associations between adaptive behaviour and thermal comfort, emphasising the need to consider individual preferences, environmental factors, and cultural norms in designing comfortable indoor environments