VGTU Journals (Vilnius Gediminas Technical University - Vilnius Tech)
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Reduction of food waste odors with probiotics and baking soda
No full textFood waste management is an important challenge for environmental protection, especially due to the unpleasant odors emitted. This study analyzes the effects of probiotics and baking soda on food waste odor reduction. The research was conducted using the dynamic olfactometry method, assessing odor concentration in different types of food waste: fish waste, dairy product waste, meat waste, and plant-based waste, i.e., fruit and vegetable waste. The experiment is carried out by placing 1 kilogram of food waste in 5-liter containers. The duration of the study is 7 days. The results showed that probiotics are more effective in reducing odors than baking soda, especially in fish and fruit and vegetable waste.
Article in Lithuanian.
Maisto atliekų išskiriamų kvapų mažinimas probiotikais ir valgomąja soda
Santrauka
Maisto atliekų tvarkymas yra svarbus aplinkos apsaugos iššūkis, o kartu ir iš atliekų skleidžiami nemalonūs kvapai. Šiame tyrime analizuojamas probiotikų ir valgomosios sodos poveikis maisto atliekų kvapų mažinimui. Tyrimas atliktas taikant dinaminės olfaktometrijos metodą, vertinant kvapo koncentraciją skirtingose maisto atliekų rūšyse: žuvies atliekose, pieno produktų atliekose, mėsos atliekose bei augalinės kilmės atliekose, t. y. vaisių ir daržovių atliekose. Eksperimentas atliktas maisto atliekas sudėjus po 1 kilogramą į 5 litrų talpyklas. Tyrimo trukmė 7 dienos. Gauti rezultatai parodė, kad probiotikai efektyviau sumažina kvapus nei valgomoji soda, ypač žuvies, vaisių ir daržovių atliekose.
Reikšminiai žodžiai: maisto atliekos, kvapų mažinimas, dinaminės olfaktometrijos metodas, probiotikai, valgomoji soda (NaHCO₃)
Dependence of cadmium, lead, and copper speciation on soil pH and temperature using VISUAL MINTEQ
No full textSoil contamination by heavy metals poses a significant threat to the environment and human health, primarily due to the toxicity of these metals and their ability to accumulate in organisms. To determine how soil pH and temperature affect the chemical speciation, mobility, and immobilization potential of cadmium (Cd²⁺), lead (Pb²⁺), and copper (Cu²⁺). The main hypothesis posits that as pH increases, the concentration of free heavy metals decreases due to the formation of complexes and precipitation, whereas an increase in temperature accelerates the kinetics of chemical reactions, thereby altering metal activity. Using the Visual MINTEQ modeling tool, simulations were carried out under various pH (4–8) and temperature (15–40 °C) conditions. The results showed that at lower pH, metal activity significantly increases; however, the influence of temperature is more complex–both positive and negative trends were observed depending on the metal. These findings provide a foundation for further research, particularly for optimizing strategies to immobilize contaminated soils. Nonetheless, certain observed trends diverged from initial assumptions and called for additional investigation.
Article in Lithuanian.
Kadmio, švino ir vario specifikacijos priklausomybė nuo dirvožemio pH ir temperatūros naudojant VISUAL MINTEQ
Santrauka
Dirvožemio užterštumas sunkiaisiais metalais kelia reikšmingą grėsmę aplinkai ir žmonių sveikatai, ypač dėl metalų toksiškumo bei jų gebėjimo kauptis organizmuose. Šio tyrimo tikslas – nustatyti, kaip dirvožemio pH ir temperatūra veikia kadmio (Cd²⁺), švino (Pb²⁺) ir vario (Cu²⁺) cheminę specifikaciją, mobilumą bei imobilizacijos potencialą. Didėjant pH laisvųjų sunkiųjų metalų koncentracija mažėja dėl kompleksų susidarymo ir nusėdimo, o temperatūros padidėjimas paspartina cheminių reakcijų kinetiką, keisdamas metalų aktyvumą. Naudojant VISUAL MINTEQ modeliavimą, atlikta simuliacija esant skirtingoms pH (4–8) ir temperatūros (15–40 °C) sąlygoms. Rezultatai parodė, kad esant žemesniam pH metalų aktyvumas reikšmingai padidėja, tačiau temperatūros poveikis yra sudėtingas – priklausomai nuo metalo, pastebimos tiek teigiamos, tiek neigiamos tendencijos. Gauti duomenys suteikia pagrindą tolesniems tyrimams, ypač siekiant optimizuoti užterštų dirvožemių imobilizacijos strategijas, nors kai kurios stebimos tendencijos neatitinka prielaidų ir reikalauja papildomos analizės.
Reikšminiai žodžiai: cheminė specifikacija, metalų mobilumas, sunkieji metalai, užterštas dirvožemis, VISUAL MINTEQ
Optimization of biogas production from Phragmites australis using first-order kinetic models
No full textThis study investigates the viability of Phragmites australis, commonly known as the common reed, as a sustainable feedstock for biogas production, emphasizing the effectiveness of pretreatment techniques to enhance biogas production. Given the invasive nature of Phragmites australis, the utilization of its biomass not only addresses environmental management challenges but also contributes to renewable energy solutions. The key objective is to evaluate mechanical and thermal pretreatment techniques on the anaerobic digestion performance of Phragmites australis using the first-order kinetic model biogas’ cumulative production and volatile solids (VS) degradation were estimated. Sensitivity analysis was used to assess how different degradation rate constants and final biogas yield affected the efficiency of biogas generation. The degradation of VS was significantly accelerated by higher temperatures and finer particle sizes. Results indicate that both mechanical and thermal pretreatment significantly enhance biogas yield and degradation rates, milling (<1 cm) and moderate thermal treatment (100 °C, 2 h) providing optimal results. These studies highlight that the selection of appropriate pretreatment methods should be based on their sustainability and effectiveness in terms of reducing energy consumption and environmental impact.
Article in English.
Biodujų gamybos iš phragmites australis optimizavimas, taikant pirmojo laipsnio kinetinius modelius
Santrauka
Šiame darbe tiriamas paprastosios nendrės Phragmites australis panaudojimas biodujų gamybai. Darbe vertinami optimalūs derliaus nuėmimo laikotarpiai bei veiksmingi pirminio apdorojimo metodai, siekiant maksimaliai padidinti metano išeigą. Atsižvelgiant į invazinį Phragmites australis pobūdį, jos biomasės naudojimas ne tik sprendžia su aplinkos taršos mažinimu susijusius iššūkius, bet ir prisideda prie atsinaujinančios energijos gamybos. Šiame tyrime taikomas pirmo laipsnio kinetinis metodas, siekiant ištirti mechaninio ir terminio apdorojimo poveikį Phragmites australis anaerobiniam apdorojimui. Taikant pirmo laipsnio kinetinį modelį buvo įvertinta kumuliatyvinė biodujų išeiga ir lakiųjų kietųjų dalelių (VS) skaidymas. Jautrumo analize buvo įvertinta, kaip skirtingos skilimo greičio konstantos ir galutinis biodujų kiekis paveikė biodujų gamybos efektyvumą. Rezultatai rodo, kad tiek mechaninis, tiek terminis pirminis apdorojimas žymiai padidina biodujų išeigą ir VS skilimo greitį, o malimas ir vidutinis terminis apdorojimas (100 °C, 2 val.) užtikrina optimalius biodujų išeigos rezultatus.
Reikšminiai žodžiai: anaerobinis skaidymas, biodujos, pirminis apdorojimas, Phragmites australis, kinetika
The study of factors affecting on COSO ERM success and its consequences: an empirical research of Thai-listed companies
No full textThe goal of this study was to look at the causes and effects of the COSO ERM success of the companies listed on the Thai Stock Exchange. The internal resources and capabilities including effective AIS design, top management support, and internal auditor competency are assumed to become the antecedents of COSO ERM success. Moreover, the consequences of COSO ERM success are sustainable value creation, achieve strategy and goal, promote efficiency and effectiveness, financial reporting quality, and compliance with law. Thai-listed firms were used as research subjects, and data from the chief internal control was collected via a mail survey process and a questionnaire. The overall findings show that successful COSO ERM is influenced positively and significantly by effective AIS design, top management support, and internal auditor competency. Additionally, the achievement of strategy and goals, promotion of efficiency and effectiveness, quality of financial reporting, and legal compliance are all positively impacted by COSO ERM success. Moreover, achieve strategy and goal, promote efficiency and effectiveness, financial reporting quality, compliance with law all have a positive, significant impact on the creation of sustainable value. Overall, the results demonstrate that excellent AIS design, top management backing, and internal auditor expertise are required for a company to develop both COSO ERM success and long-term sustainable value generation
One-signed rotationally symmetric solutions of singular Dirichlet problems with the prescribed higher mean curvature operator in Minkowski spacetime
No full textWe investigate the existence, uniqueness and multiplicity of one-signed rotationally symmetric solutions of singular Dirichlet problems with the prescribed higher mean curvature operator in Minkowski spacetime. The main tools are the Schauder fixed point theorem along with cut-off technique and the Leggett-Williams fixed point theorem. In addition, we give some practical models to illustrate the effectiveness of our results
Railway multi UAV collaborative encirclement strategy based on Grey Wolf optimization dynamic encirclement points
No full textTo address the threat of invading drones along railway lines, this paper proposes a multi-UAV cooperative capture strategy based on the Grey Wolf Optimizer (GWO) algorithm and dynamic capture points. Firstly, a motion model in three-dimensional space is established according to the movement characteristics of invading drones along railway lines. Secondly, three-dimensional capture points are dynamically generated based on the movement direction of invading drones, and a negotiation allocation mechanism is designed to achieve optimal matching between capture points and UAVs. Then, an objective function combining path consumption and encirclement effect is constructed, and the GWO algorithm is used to optimize the UAV heading angle increment in real-time. Finally, the effectiveness of the algorithm is verified through three-dimensional simulations. The simulations show that this strategy can achieve efficient capture in three-dimensional environments. Compared with strategies without GWO optimization, the average capture time is reduced by 55.5%, and the capture success rate is improved by 4.8%. Furthermore, in comparison with other mainstream optimization algorithms such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA), and Differential Evolution (DE), our approach yields superior performance in both the average number of capture steps (55.7 steps) and success rate (100%), providing an efficient and reliable technical solution for railway airspace security protection
Environmental, social, and governance practices and reporting readiness in small and medium-sized enterprises
No full textFollowing the European Sustainability Reporting Standards (ESRS), in 2026, the non-financial reporting obligation will be extended to small and medium-sized enterprises listed on the regulated market and meet employment and financial criteria. The obligation will also affect their contractors, suppliers, customers, and all stakeholders that influence a company’s overall Environmental, Social, and Governance (ESG) performance. The study aims to identify the Small and Medium-sized Enterprises’ (SME) practices in the field of ESG and recognise whether they are ready to report on their ESG activities. A quantitative method was used to obtain a general picture of the approach to ESG practices. The study was conducted among 300 Polish companies. The study results show that about half of the surveyed small and medium-sized enterprises conduct ESG activities and monitor ESG indicators. More than half demonstrate basic or good readiness for ESG reporting following the adopted criterion. This study’s contribution is twofold. First, it enriches the current state of knowledge by adding original insights into the ESG practices of SMEs, while most existing studies focus on the ESG activities of large enterprises. Second, the study’s novelty is its attempt to assess the readiness for ESG reporting at the corporate and country levels
Relevance of the real estate agent in the Spanish residential market in the age of digitalisation
No full textDigitalization has reshaped the real estate industry, significantly transforming the role of the agent. In an era of disruptive technologies, real estate agents face both new challenges and opportunities, where adaptability and the integration of digital tools are essential for success. This article examines how digitalization has influenced the agent’s role and assesses its importance in the brokerage process from the customer’s perspective. Self-administered online surveys have been used for data gathering, obtaining 412 valid responses from people who have participated in the process of buying or selling a property in Spain. Results reveal the need for the agent who still plays a decisive role in the buying and selling process and is considered well prepared, providing confidence for many clients. Digitalization has redefined the agent’s profile, requiring a combination of technical and human skills and the importance of empathy and personal contact has become crucial. Those professionals who incorporate technology while focusing on delivering an exceptional customer experience will be the ones who thrive in this new era of digitalized real estate. The manuscript enriches academic literature on the importance of the real estate agent in a country such as Spain where it has been hardly studied
Collaborative analysis model of construction schedule and quality for RCC dam based on DES and deep learning
No full textConstruction schedule simulation is an effective method to analyze the progress of concrete rolling construction and its simulation accuracy is an important indicator that project managers care about. However, existing roller compacter concrete construction simulation research pays less attention to the impact of construction process changes caused by compaction quality on simulation accuracy. Based on the real-time monitoring system of concrete rolling construction, this paper establishes a simulation model of concrete rolling construction considering compaction quality. The model firstly reconstructs the property parameters of roller compacted concrete using the improved generated adversarial network, secondly, considering the nonlinear correlation characteristics of parameters affecting compaction quality, a concrete compaction quality analysis model based on improving grey wolf optimized convolutional neural networks (IGWO-CNN) was built. Finally, the intelligent analysis model of compaction quality was embedded into the simulation model of concrete rolling construction. Based on real-time monitoring data, the simulation model was driven and the simulation process was adjusted adaptively. Taking the construction of a roller compacted concrete dam in China as an example, the validity and superiority of this model are proved
A systematic review on safety practices in high-rise building construction: benefits, barriers, and strategic improvements
No full textHigh-rise building construction has long been considered one of the most dangerous jobs globally. However, there is currently a lack of comprehensive systematic reviews that approach the implementation of safety practices in high-rise construction. This study aims to fill the following research gaps: first, to understand the significance and identify the barriers faced to implementing safety practices in high-rise construction; second, to propose a framework to improve safety performance. A total of 109 articles from databases were thoroughly reviewed in this study.
The research identified six categories of benefits, five types of safety barriers, and 15 strategies proposed to overcome these barriers. In terms of the number of sources, “reduced accident rates” and “improved organizational reputation” were identified as the top benefits in terms of the significance of safety practices. “Lack of health and safety training” was deemed the largest barrier. To address these challenges, this paper explores the strategies and risk mitigation measures from the perspectives of six stakeholders: regulatory agencies, government, owners, contractors, consultants, and workers. The findings suggest that establishing strict market entry mechanisms are fundamental while strengthening worker safety training and conducting regular safety inspections and real-time site monitoring are the most effective methods