Innovative approaches for estimating the efficiency of a single-tilt solar still: a comprehensive theoretical and numerical analysis

Shaping spherical porous carbon beads impregnated with K₂CO₃ for CO2 capture in humid flue gases and indoor air with low pressure drop

• A moving-bed thermochemical energy storage system is experimentally investigated. • Pumice-based salt-in-matrix composite sorbents are developed and implemented. • The system achieves an energy storage density of 189.7 kWh/m 3 . • Maximum effective energy and exergy efficiencies are 52.7% and 6.8%, respectively. • A correlation between air humidity difference and temperature lift is established. In the last decade, low-grade thermochemical energy storage systems have been gaining interest due to their long-term heat storage potential and high energy storage density. Despite the advantageous aspects of this heat storage method, previously investigated fixed-bed reactors suffer from low heat and mass transfer performance and offer limited process control. In order to overcome these challenges, a new multi-layer moving bed reactor was designed, manufactured, and tested in this study. The proposed reactor consists of reaction and storage sections where eight independent sorption beds have freedom of movement between the two sections. Such a design enables a modular concept, where each sorption bed could be charged or discharged individually, while the remaining sorption beds are stored inside their own hermetically insulated chambers. In the system, two different sizes of pumice stones, namely PM1 and PM2, were used as the host matrix, and three different thermochemical materials were synthesized by impregnation of the LiCl-CaCl 2 mixture and CaCl 2 as salts into pumice. During the experiments, comparative analyses of different materials, short-cycle full-system analyses, long-cycle energy density analyses, and multi-bed performance analyses have been performed. Additionally, the impact of air velocity was investigated. The evaluations were performed based on the First and Second Laws of Thermodynamics. Study results demonstrated that each sorption bed provides an average heat output between 0.58 and 1.07 kW depending on the inlet air conditions and the composition of thermochemical material. According to the study results, the energy storage density of the system was obtained as 189.7 kWh/m 3 with the use of PM2-CaCl 2 . On the other hand, 4.2 m/s was found as the most optimal air velocity, proving the highest average heat output during the discharging process and the highest moisture desorption rate per unit of heat consumed during the charging process. A linear correlation between the air absolute humidity difference and the air temperature lift for the discharging process was also obtained, which could provide useful insights for the performance prediction of thermochemical energy storage systems.

The increasing share of renewables forces combustion-driven power generation machines to operate with high adaptability. Small-scale heat and power units, like micro gas turbines (mGT), could show potential for Hybrid Renewable Energy Systems (HRES) due to their operational and fuel flexibility. However, their economic viability in a variable energy environment remains uncertain. The levelized cost of exergy (LCOX) in HRES with combined heat and power (CHP) units, should be calculated under uncertainties to support decision-making. This paper applies design optimization to a photovoltaic/battery/heat pump system with two prime movers to investigate the required economic relevance of small-scale CHP units in HRES. The considered prime movers are internal combustion engines (ICE) and mGTs, including advanced mGT configurations such as humidified cycles (mGT-wet, mHAT). Test cases include a hospital, office and hotel in Brussels with distinct demand profiles. Uncertainty quantification on optimized system capacities is performed using Polynomial Chaos Expansions (PCE), ensuring computational efficiency. The hospital shows that adding an mGT improves LCOX (227 €/MWh compared to 244 €/MWh of non-PM HRES), while in the hotel case, non-PM systems are more cost-effective due to low electricity demand. Dry mGTs and ICEs enhance flexibility in HRES for suitable applications, but their economic viability depends strongly on energy prices and demand. Humidified mGTs improve self-sufficiency but with higher fuel cost, making their cost-effectiveness questionable if excess electricity is not sold to the grid. • Techno-economic analysis of mGTs in hybrid renewable energy systems. • Optimization balances levelized cost of exergy and self-sufficiency. • Potential of applying CHP units in buildings with high energy demand. • Heat recovery steam generator use is key for cost-effective mGT systems in hospitals. • Micro humid air turbine suits users shifting cost sensitivity from electricity to gas.

Numerical simulation and parametric study of effective parameters in a thermoelectric dehumidifier with cooled plate using the Peltier effect

Climatic characteristics, particularly temperature and ambient humidity, significantly affect the qualitative and quantitative indicators of flax production and fibre formation. Conventional technologies for obtaining flax fibre are based on natural dew retting, the efficiency of which depends on atmospheric moisture. The decrease in air humidity during summer periods due to climate change complicates the biological processes involved in the transformation of flax stems into retted straw. A separate harvesting technology involving low cutting of stems and their placement into windrows has been proposed to utilize productive soil moisture during retting and to accelerate seed harvesting. During field laying, windrows change their geometric parameters, become denser, and increase adhesion both between stems and with the soil surface, which requires periodic lifting and loosening. This paper presents the results of field experimental studies conducted using a developed experimental picker to determine rational structural and technological parameters based on a four-factor experimental design. Changes in windrow geometry and their interaction with the working elements of the picker were analysed. Optimal parameters of the picker for flax retting preparation were established. The study is aimed at developing a new technical solution for flax harvesting.

Smallholder farmers across India, including those in and around Uttar Pradesh, still manage irrigation the way their grandparents did: they walk to the field, look at the soil, and make a call. Some days that means too much water; other days, not nearly enough. Neither outcome is good for crops or for a region where water is already under stress [11]. This paper describes an IoT-driven irrigation system that our three-member team designed, assembled, and tested as our final-year project. The hardware is built around a NodeMCU ESP8266 [5], a resistive soil moisture sensor, and a DHT11 module [?] for tracking air temperature and humidity. Together they push readings to the Blynk cloud platform [4] over Wi-Fi every two seconds, where the data shows up on a smartphone dashboard in near-real time. When soil moisture drops below a threshold set in the firmware, a relay module closes the pump circuit and irrigation begins—no one needs to be present. We ran the prototype through several hours of testing across different soil wetness levels and found that pump response was consistently fast, remote visibility worked as intended, and the total component cost came out at Rs. 4500, well inside our starting budget.

Diamond-like carbon (DLC) coatings are widely used as protective and self-lubricating surfaces in metal–metal contacts. Their frictional behavior is governed by the formation and evolution of carbon-rich transfer layers (TLs), which can be tailored through functionalization with carbon nanomaterials. Recent studies have shown that graphene sheets (GSs) and nanodiamonds (NDs) act synergistically to achieve ultra-low friction in microrough (~0.2 μm) metal–DLC contacts under dry N2 at a 1 N load. Here, we probe how this lubrication mechanism evolves with increasing load from 1 to 10 N—corresponding to local contact pressures up to ~11–16 GPa—respectively, in dry N2 and humid air conditions. Ball-on-disk experiments are performed on an industrial hydrogenated DLC coating sliding against stainless-steel. In dry N2, GS–ND functionalization yields a low and stable coefficient of friction across the entire load range, reaching a minimum of about 0.05. In humid air, higher friction levels are observed across all loads (CoF ~0.10–0.15), accompanied by oxidation-driven modifications of both wear debris and the counterface contact region, with oxygen content increasing by more than a factor of three compared to dry N2. Detailed microscopy and spectroscopy analyses indicate that enhanced lubricity in dry N2 arises from TLs incorporating GSs, NDs, and nanoscroll-like structures, whereas humid air promotes interfacial amorphization and oxidation, leading to load-insensitive friction and boundary lubrication effects through physisorbed water molecules.

The rapid global transition toward electric vehicles (EVs) represents a critical shift in the automobile industry, driven by the urgent need to reduce greenhouse gas emissions and achieve sustainable mobility. However, the adoption of EV technology in developing countries such as Bangladesh presents unique challenges, particularly due to climatic conditions, infrastructural limitations, and policy gaps. This thesis investigates the design and policy framework for climate-optimized electric vehicle battery systems in Bangladesh, with a focus on enhancing performance, safety, and long-term sustainability. A key challenge addressed in this study is the impact of Bangladesh’s tropical climate on lithium-ion battery performance. High ambient temperatures and humidity levels contribute to thermal stress, accelerated degradation, and reduced efficiency of battery systems. To address this issue, the research explores various battery thermal management systems (BTMS), including air cooling, liquid cooling, and phase-change materials, through simulation-based analysis. The objective is to identify the most effective and economically feasible solution suitable for local environmental conditions. In addition to engineering design, this study examines the current policy landscape governing electric mobility in Bangladesh. It identifies gaps in regulatory frameworks, infrastructure development, and technological adaptation that hinder the widespread adoption of EVs. By integrating engineering insights with policy analysis, the research proposes a comprehensive framework aimed at supporting the development of a resilient EV ecosystem. The findings of this study contribute to both academic and practical domains by offering a localized approach to EV technology adaptation while aligning with global sustainability goals. Ultimately, this research provides a foundation for future innovation, policy formulation, and international collaboration in advancing Bangladesh’s automobile sector toward a more sustainable and globally integrated future.

The agricultural sector, particularly horticulture, faces significant challenges due to global climate change, causing unstable crop yields and quality. Traditional greenhouses in tropical regions often suffer from a heat trap effect, which induces plant stress if not properly managed. Current environmental control systems rely heavily on manual labor or simple on/off thresholds, leading to energy inefficiency and delayed responses. This study aims to design and simulate an internet of things (iot)-based smart greenhouse control system utilizing a fuzzy logic controller (flc) with the mamdani method. Unlike previous partial control studies, this research integrates four vital parameters simultaneously: air temperature, air humidity, soil moisture, and light intensity. The hardware architecture incorporates an esp32 microcontroller, dht22 and dht11 sensors, a capacitive soil moisture sensor, an ldr module, and actuators including a dc fan, water pump, and led grow lights. Simulation results using proteus software demonstrate that the fuzzy logic algorithm successfully regulates actuator speeds via pulse width modulation (pwm) based on environmental transitions, effectively preventing component chattering. Furthermore, the system successfully transmits real-time microclimate data to the blynk platform for remote monitoring. This integrated approach offers a more precise, energy-efficient, and adaptive solution for optimizing horticultural microclimates.

The phenomenon of coal self-heating represents a critical risk during loading operations at Muara Jawa Port, as it can lead to temperature escalation, smoke generation, and potential fire hazards. This study examines the causes of coal self-heating, assesses its risk level, and evaluates the conformity of handling practices with the IMSBC Code and the IMDG Code. A descriptive qualitative approach was employed, involving direct observation aboard MV Golden Ace, temperature measurements using a thermal scanner, and risk analysis through Hazard Identification and Risk Assessment (HIRA). The findings indicate that coal temperatures reached 61°C, exceeding the safe threshold of 55°C as stipulated by the IMSBC Code, thereby necessitating the suspension of loading operations to allow for cooling. The HIRA results identify the highest risk phase occurring during the transfer of coal from barges to grab cranes, due to increased exposure to air and high humidity levels. While several operational procedures were found to be compliant with existing regulations, shortcomings remain in temperature documentation and gas monitoring practices. This study underscores the importance of early detection, continuous temperature surveillance, and effective mitigation strategies to enhance operational safety in coal loading activities.

Agriculture plays a crucial role in ensuring global food security and economic stability. However, traditional farming practices often face challenges such as inefficient water usage, delayed disease detection, and improper nutrient management. These issues reduce crop productivity and increase farming costs. To address these problems, this research proposes an Integrated Smart Agriculture System that combines Internet of Things (IoT) technology and machine learning techniques. The system collects real-time environmental and soil data using sensors deployed in agricultural fields. Parameters such as soil moisture, temperature, humidity, and nutrient levels are continuously monitored. The collected data is analyzed using the Random Forest machine learning algorithm to predict crop health conditions and provide appropriate farming recommendations. The proposed system helps farmers make data-driven decisions related to irrigation, fertilization, and harvesting. Experimental results demonstrate that the system improves crop yield, optimizes resource usage, and supports sustainable agriculture. The proposed system provides a scalable and cost-effective solution for modern precision agriculture.

As an efficient dry separation technology, electrostatic separation exhibits significant potential for application in the sorting and recovery of carbon-rich resources from coal gasification fine slag (CGFS). The small particle size and high moisture content of CGFS particles are the main factors affecting the efficiency of separation. This study proposes a method integrating particle moisture reduction and charging promotion based on molecular sieves, with the aim of investigating its feasibility in improving the electrostatic separation efficiency of CGFS particles. The results indicate that molecular sieves can effectively adsorb moisture from the ambient humid air and the surface of particles, allowing for rapid drying of wet particles. The reduction in moisture content on the particle surfaces significantly promotes their charging capability, creating favorable conditions for electrostatic separation. After molecular-sieve-assisted charging enhancement, the carbon content in the ash-enriched positive plate product decreased by 4.96%, while the carbon content in the carbon-enriched negative plate product increased by 12.15%, indicating a significant improvement in carbon–ash separation efficiency. Correspondingly, the decarbonization efficiency of the positive plate and carbon recovery efficiency of the negative plate were increased by 21.30% and 52.17%, respectively. Furthermore, when the moisture content exceeds 10%, the phenomenon of inter-particle agglomeration can adversely affect the separation of carbon and ash particles. The most suitable operating conditions are a moisture content no higher than 10%, an electric field density of 30 kV/m, a filling molecular sieve of 400 g, and a gas velocity of 12 m/s (volumetric flow rate 84.78 m3/h). In practical industrial applications, it is advisable to consider pre-treating the particles for drying or employing secondary separation to enhance sorting accuracy.

Introduction. Chronic stress and paracetamol exposure are among the most relevant factors affecting neurochemical and molecular processes in the brain in modern humans. Excessive activation of inflammatory and oxidative pathways during chronic psychosocial stress can lead to a decrease in the expression of neuroprotective and antioxidant genes, exacerbating the neurotoxic effects of drugs such as paracetamol.Objective. To assess the effect of chronic unpredictable stress and oral administration of paracetamol, as well as their combined effect on the morphological state of the brain and on the expression of genes of the antioxidant system and neurotrophic factor in the hippocampus in rats.Materials and methods. The experiment was conducted on forty eight rats (males and females in equal numbers), divided into four groups: control, chronic stress, paracetamol, combined exposure to stress and paracetamol. A complex of various stressors was used to model chronic stress. Paracetamol was administered orally at a dose of 1000 mg/kg. The morphological state of the hippocampus was assessed histologically, gene expression - by quantitative real-time PCR. Statistical analysis included bootstrapping and correction for multiple comparisons using the Holm-Bonferroni method.Results. Macroscopic and histological examination of the rat brain showed the preservation of the normal anatomical structure and integrity of the hippocampal tissues in all groups. Statistical analysis of gene expression showed animals treated with paracetamol (groups III and IV) to show a significant decrease in the mRNA levels in the Sod1 and Bdnf genes in the hippocampus compared to the control and the group exposed to stress only (group II). The expression level of Sod1 and Bdnf was significantly lower in both males and females in these groups (p = 0.001). For the Hmox1 gene, a significant decrease in expression was found only in males in the paracetamol-treated group, while no changes were noted in females.Limitations. Laboratory animals of the same biological species were used for the experiment, and the toxicant was used in only one concentration.Conclusion. Thus, paracetamol, both in isolated use and in combination with chronic stress, has a more pronounced inhibitory effect on the expression of key genes of antioxidant protection and neurotrophic support than stress alone.Compliance with ethical standards. Date of the meeting of the bioethics commission of theUfa Research Institute of Occupational Medicine and Human Ecology dated 02/08/2024 No. 01–02. Throughout the study, the animals were kept in standard conditions with 12-hour artificial lighting during the daytime, a relatively constant level of humidity (30–70%) and an air temperature of 20–25 °C. All animal manipulations were carried out in strict compliance with the rules prescribed in the basic regulatory documents, including the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (Strasbourg, 1986) and the Helsinki Declaration on the Humane Treatment of Animals.Contributions: Gizatullina A.A. – concept and study design, material collection and processing, statistical analysis, manuscript writing; Valova Ya.V. – material collection and processing, statistical analysis; Mukhamadieva G.F. – editing; Karimov D.O. – concept and study design, statistical analysis; Karimov D.D. – material collection and processing; Ryabova Yu.V. – material collection and processing; Khusnutdinova N.Yu. – material collection and processing; Khmel A.O. – material collection and processing. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Conflict of interest. The authors declare no conflict of interest.Funding. Industry research program of Rospotrebnadzor for 2021–2025 “Scientific substantiation of the national system for ensuring sanitary and epidemiological welfare, managing health risks and improving the quality of life of the population of Russia”, on the topic: 6.9.1.2 “Study of the impact of chemical production factors under conditions of chronic stress” No. NIOKTR I124021200153-3.Received: April 30, 2025 / Revised: July 9, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

The formation of the microbiocenosis of newborns is one of the key factors of early postnatal adaptation and largely determines the child’s health status in subsequent stages of life. In the mountainous regions of the Kyrgyz Republic, this process occurs under specific environmental conditions, including chronic hypoxia, low ambient temperatures, reduced atmospheric pressure, and decreased air humidity, which may significantly influence microbial colonization in newborns. The aim of this study was to investigate the features of microbiocenosis formation in newborns living at different altitude levels, taking into account the maternal microbial profile. Materials and methods included a microbiological examination of the oropharyngeal and nasal mucosa, as well as the skin of parturient women and their newborns permanently residing in low-, mid-, and high-altitude regions of the Kyrgyz Republic. The assessment of microflora was performed based on both qualitative and quantitative characteristics of microorganisms. The results demonstrated that in low-altitude conditions, the microbiological profiles of mothers and newborns generally corresponded to physiological norms. In mid-altitude areas, an increased prevalence of opportunistic microorganisms was observed, including Staphylococcus aureus, Candida krusei, and representatives of Gram-negative microflora. In high-altitude regions, maternal-to-newborn transmission of microflora was less frequent; however, quantitative indicators of microorganisms in newborns often exceeded diagnostically significant thresholds. The obtained findings confirm the significant role of environmental altitude-related factors in the formation of the microbiocenosis of newborns and substantiate the need for differentiated preventive and sanitary-hygienic measures in maternity healthcare facilities located in mountainous regions.

This study investigates the performance of three commercially available structural adhesives (two epoxy-based formulations and one polyurethane adhesive) for bonding ceramic tiles to composite sandwich panels consisting of an aluminium honeycomb core with glass fibre–epoxy skins. The bonded assemblies were subjected to accelerated thermo-hygrometric ageing through repeated environmental cycles (14, 28, 56, and 112 cycles), with temperatures ranging from −10 °C to 50 °C and relative humidity levels up to 95%. Mechanical performance was evaluated using pull-off tests to determine the tensile strength and load-bearing capacity of the joints. Complementary material characterisation techniques, including differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), were employed to investigate the thermal stability, chemical integrity, and failure mechanisms of the adhesives. The results show that the tested adhesives retained good thermal and chemical stability after environmental cycling, with only minor reductions in glass transition temperature and no significant chemical changes detectable within FTIR sensitivity. Mechanical testing revealed different ageing responses among the adhesives: the polyurethane adhesive exhibited the highest initial tensile strength, whereas one epoxy formulation demonstrated the highest resistance to environmental ageing, showing only a 12.8% reduction in tensile strength after 112 cycles. Mixed adhesive–cohesive failure modes were predominantly observed, indicating partial interfacial degradation while preserving the bulk integrity of the adhesive layer. Overall, the results demonstrate that both epoxy- and polyurethane-based adhesives can provide suitable bonding performance for façade systems involving composite sandwich panels and ceramic tiles, although their durability depends on both initial mechanical performance and resistance to thermo-hygrometric ageing.

Aerogel materials often aim for high elasticity, which typically compromises strength. This challenge in balancing elasticity and strength constrains their applications in wearable circuits, intelligent robots, and flexible sensors. This study presents a topological isomerization strategy based on molecular chain rearrangement to enhance both the elasticity and strength of cellulosic triboelectric aerogels. During the molecular chain rearrangement, ethylenediamine forms competitive hydrogen bonds with hydroxyl groups, disrupting the inherent hydrogen bond network of cellulose and exposing additional active hydroxyl groups. Furthermore, through in situ interfacial polymerization and covalent crosslinking, a polymer topological network is established. This results in a flexible cellulosic triboelectric aerogel with improved elasticity and strength; even after 20,000 cycles of compression, the aerogel exhibited a recoverability exceeding 95% and could support loads over 2000 times its own weight. Concurrently, the transformation of the crystal structure due to the reconstruction of the hydrogen bond network leads to the rearrangement of surface functional groups, which modifies the surface potential and ensures stable triboelectric output across a broad range of temperatures and humidity levels. This strategy provides innovative methods for the design and fabrication of lightweight, ultra-elastic, and extreme-environment-resistant 3D porous materials, which are essential for advancing next-generation sensor devices.

A major challenge for aircraft fuel cell propulsion systems is to ensure that the air properties on the cathode side remain within a narrow, suitable envelope throughout the flight. The components must maintain almost constant temperature, pressure and humidity levels under widely varying ambient conditions. The choice of components must take into account the aviation-specific requirements for weight and waste heat. In this numerical study, we investigate a novel cathode air supply system for a hydrogen fuel cell propulsion system which replaces the state-of-the-art electrical components used to drive the compressor in the cathode air supply system with a hydrogen-fuelled micro gas turbine. Previous studies have shown the potential of waste heat and overall cathode gas path size reduction but the off-design performance of such system is yet to be investigated. Hence, based on realistic regional aircraft flight missions and realistic atmospheric conditions, we investigate the off-design performance of the propulsion system. Therefore, a constant mass flow algorithm along cathode and gas turbine gas paths is developed and presented. Next, earth observation data are used to determine realistic boundary conditions and air contamination. Based on these data, the possible contaminant ingestion of the fuel cell is evaluated to allow for future sizing of filters for robust operation. Furthermore, the effects of realistic ambient conditions on the thermodynamic cycle yield important information about necessary revisions of the cycle design point.

Agriculture plays a vital roleintheeconomy,andefficientmonitoringofagriculturalparametersisessentialtoimprovecropproductivity and resource utilization. Traditional farming methods rely heavily on manual monitoring, which is timeconsuming, labour-intensive, and often inaccurate. To overcome these limitations, this project proposes an IoT-basedWireless Sensor Network (WSN) for real-time monitoring and control of agricultural parameters. In the proposed system,various sensors such as soil moisture, temperature, humidity, and water level sensors are deployed in the agricultural fieldto continuously collect environmental data. The sensor data is transmitted wirelessly to a microcontroller, which processesthe information and sends it to an IoT cloud platform using a Wi-Fi module. Farmers can remotely monitor real-time fieldconditions through a web or mobile application from anywhere at any time. Based on predefined threshold values, thesystem can automatically control agricultural operations such as irrigation, ensuring optimal water usage and reducinghuman intervention. The proposed IoT-based system enhances decision-making, improves crop yield, minimizes waterwastage, and reduces operational costs. This smart agriculture solution provides a reliable, scalable, and cost-effectiveapproach for modern farming practices.Keywords — Control of Agricultural Parameters, Arduino, IoT, Wireless Sensor Network, Real-time Monitoring, SolarPowered Smart Farming, Precision Agriculture

Background Recurrent large wildfires have become a global problem threatening human lives and assets. Extreme fire weather conditions and cured biomass increase the chances of severe and high-intensity fires that can be hard to control. The Cerrado is a tropical humid savanna with frequent, late dry season (LDS) large wildfires prevailing in protected areas. Since 2014, prescribed early dry season (EDS) fires have been applied within the integrated fire management approach. Aims To assess effects of relative humidity and fuel load on fire intensity and fuel consumption. Methods We undertook experimental fires during early and late dry seasons, during day and evening and in areas with different fuel loads. Key results We found that: (1) EDS fires under lower air relative humidity daytime conditions yielded similar fire intensities to LDS fires; (2) under higher relative humidity evening conditions, EDS fires exhibited lower intensities, which also varied with available fuels in different years. Conclusions Fire management in Cerrado landscapes should consider taking advantage of different diurnal, seasonal and fuel load conditions to address specific management objectives. Implications Acknowledging different local conditions can enhance management cost benefits.