Search Results (313)

LPG fuel supply systems are increasingly important for improving energy efficiency and reducing carbon emissions in the shipping industry. The primary objective of this research is to investigate the heat transfer phenomena to enhance the thermal performance of double-pipe heat exchangers (DPHEs) in LPG fuel supply systems. This study investigates the heat transfer performance of a glycol–steam double-pipe heat exchanger (DPHE) within an LPG fuel supply system under varying operating conditions. A computational model and methodology were developed and validated by comparing the numerical results with experimental data obtained from commissioning tests. Additionally, the effects of turbulence models and parametric variations were evaluated by analyzing the glycol–water mixing ratio and flow direction—both of which are critical operational parameters for DPHE systems. Numerical validation against the commissioning data showed a deviation of ±2% under parallel-flow conditions, confirming the reliability of the proposed model. With respect to the glycol–water mixing ratio and flow configuration, thermal conductance (UA) decreased by approximately 11% in parallel flow and 13% in counter flow for every 20% increase in glycol concentration. Furthermore, parallel flow exhibited approximately 0.6% higher outlet temperatures than counter flow, indicating superior heat transfer efficiency under parallel-flow conditions. Finally, the heat transfer behavior of the DPHE was further examined by considering the effects of geometric characteristics, pipe material, and fluid properties. This study offers significant contributions to the engineering design of double-pipe heat exchanger systems for LPG fuel supply applications. Full article

Azospirillum is a well-studied genus of plant growth-promoting rhizobacteria (PGPR) and one of the most extensively researched diazotrophs. This genus can colonize rhizosphere soil and enhance plant growth and productivity by supplying essential nutrients to the host. Azospirillum–plant interactions involve multiple mechanisms, including nitrogen fixation, the production of phytohormones (auxins, cytokinins, indole acetic acid (IAA), and gibberellins), plant growth regulators, siderophore production, phosphate solubilization, and the synthesis of various bioactive molecules, such as flavonoids, hydrogen cyanide (HCN), and catalase. Thus, Azospirillum is involved in plant growth and development. The genus Azospirillum also enhances membrane activity by modifying the composition of membrane phospholipids and fatty acids, thereby ensuring membrane fluidity under water deficiency. It promotes the development of adventitious root systems, increases mineral and water uptake, mitigates environmental stressors (both biotic and abiotic), and exhibits antipathogenic activity. Biological nitrogen fixation (BNF) is the primary mechanism of Azospirillum, which is governed by structural nif genes present in all diazotrophic species. Globally, Azospirillum spp. are widely used as inoculants for commercial crop production. It is considered a non-pathogenic bacterium that can be utilized as a biofertilizer for a variety of crops, particularly cereals and grasses such as rice and wheat, which are economically significant for agriculture. Furthermore, Azospirillum spp. influence gene expression pathways in plants, enhancing their resistance to biotic and abiotic stressors. Advances in genomics and transcriptomics have provided new insights into plant-microbe interactions. This review explored the molecular mechanisms underlying the role of Azospirillum spp. in plant growth. Additionally, BNF phytohormone synthesis, root architecture modification for nutrient uptake and stress tolerance, and immobilization for enhanced crop production are also important. A deeper understanding of the molecular basis of Azospirillum in biofertilizer and biostimulant development, as well as genetically engineered and immobilized strains for improved phosphate solubilization and nitrogen fixation, will contribute to sustainable agricultural practices and help to meet global food security demands. Full article

This study explores the impact of graphene integration on lithium niobate (LiNbO₃, LN) ridge waveguides and directional couplers, focusing on coupling efficiency, polarization-dependent light absorption, and temperature sensitivity. Experimental and simulation results reveal that graphene loading significantly alters the effective mode refractive index and enhances waveguide coupling, enabling precise control over light transmission and power distribution. The temperature-dependent behavior of graphene–LN structures demonstrates strong thermal sensitivity, with notable changes in output power ratios between cross and through ports under varying temperatures. These findings highlight the potential of graphene–LN hybrid devices for compact, high-performance photonic circuits and temperature sensing applications. This study provides valuable insights into the design of advanced integrated photonic systems, paving the way for innovations in optical communication, sensing, and quantum technologies. Full article

Under the influence of global climate change, water conservancy projects located in the high-latitude cold regions of the world are facing severe challenges. This study addresses the contradiction between water supply stability and ecological flow during the dry season in cold regions. Taking Linhai Reservoir as the core, it integrates the HEC-RAS hydrodynamic model with multi-source data such as basin topography, hydro-meteorological data, and water conservancy project parameters to construct a multi-scenario water supply scheduling model during the dry season. The aim is to provide scientific recommendations for different reservoir operation strategies in response to varying frequencies of upstream inflow, based on simulations conducted after the reservoir’s completion. Taking into account winter runoff reduction characteristics and engineering parameters, we simulated the relationships between water level and flow, ecological flow requirements, and urban water shortages. The results indicate that in both flood and normal years, dynamic coordination of storage and discharge can achieve a daily water supply of 120,000 cubic meters, with 100% compliance for the ecological flow rate. For mild and moderate drought years, additional water diversion becomes necessary to achieve 93.5% and 89% supply reliability, respectively. During severe and extreme droughts, significantly reduced reservoir inflows lower ecological compliance rates, necessitating emergency measures, such as utilizing dead storage capacity and exploring alternative water sources. The study proposes operational strategies tailored to different drought intensities: initiating storage adjustments in September for mild droughts and implementing peak-shifting measures by mid-October for extreme droughts. These approaches enhance storage efficiency and mitigate ice blockage risks. This research supports the water supply security and river ecological health of urban and rural areas in Mudanjiang City and Hailin City and provides a certain scientific reference basis for the multi-objective coordinated operation of reservoirs in the same type of high-latitude cold regions. Full article

Groundwater storage refers to the water stored in the pore spaces of underground aquifers, which has been increasingly affected by both climate change and anthropogenic activities in recent decades. Therefore, monitoring their changes and the factors that affect it is of great importance. Although the influence of natural factors on groundwater is well-recognized, the impact of human activities, despite being a major contributor to its change, has been less explored due to the challenges in measuring such effects. To address this gap, our study employed an integrated approach using remote sensing and the Google Earth Engine (GEE) cloud-free platform to analyze the effects of various anthropogenic factors such as built-up areas, cropland, and surface water on groundwater storage in the Lake Urmia Basin (LUB), Iran. Key anthropogenic variables and groundwater data were pre-processed and analyzed in GEE for the period from 2000 to 2022. The processes linking these variables to groundwater storage were considered. Built-up area expansion often increases groundwater extraction and reduces recharge due to impervious surfaces. Cropland growth raises irrigation demand, especially in semi-arid areas like the LUB, leading to higher groundwater use. In contrast, surface water bodies can supplement water supply or enhance recharge. The results were then exported to XLSTAT software2019, and statistical analysis was conducted using the Mann–Kendall (MK) non-parametric trend test on the variables to investigate their potential relationships with groundwater storage. In this study, groundwater storage refers to variations in groundwater storage anomalies, estimated using outputs from the Global Land Data Assimilation System (GLDAS) model. Specifically, these anomalies are derived as the residual component of the terrestrial water budget, after accounting for soil moisture, snow water equivalent, and canopy water storage. The results revealed a strong negative correlation between built-up areas and groundwater storage, with a correlation coefficient of −1.00. Similarly, a notable negative correlation was found between the cropland area and groundwater storage (correlation coefficient: −0.85). Conversely, surface water availability showed a strong positive correlation with groundwater storage, with a correlation coefficient of 0.87, highlighting the direct impact of surface water reduction on groundwater storage. Furthermore, our findings demonstrated a reduction of 168.21 mm (millimeters) in groundwater storage from 2003 to 2022. GLDAS represents storage components, including groundwater storage, in units of water depth (mm) over each grid cell, employing a unit-area, mass balance approach. Although storage is conceptually a volumetric quantity, expressing it as depth allows for spatial comparison and enables conversion to volume by multiplying by the corresponding surface area. Full article

This study proposes a polygeneration system that integrates an absorption cooling system, a heat transformer, and an organic Rankine cycle for the simultaneous production of power, cooling, and freshwater—the former operating with a water/lithium bromide mixture while the organic Rankine cycle operates with R123. The system was simulated at temperatures between 100 °C and 150 °C and with heat supply capacities that a geothermal field in Nayarit, Mexico, could provide. A parametric analysis was conducted by developing a mathematical model using the Engineering Equation Solver software. The geothermal source temperatures, ambient temperatures, and mass ratios were varied to determine the power, cooling load, freshwater production, and energy utilization factor under different operating conditions. The results showed that the system could produce up to 13 kW of power, 100 kW of cooling, and 50 L per hour at a heat source temperature of 150 °C. The energy utilization factor varied from 0.32 to 0.43, which means that up to 43% of the energy supplied to the system could be utilized to produce cooling, freshwater, or power. Full article

The relationship between silvicultural strategies, manifested in the thinning method and rotation age on sites with different water supply, and the mechanical properties of engineered wood products plywood and laminated veneer lumber has been analyzed. Sample logs from five German sites of Norway spruce (Picea abies (L.) Karst.) and Douglas fir (Pseudotsuga menziesii (M.) Franco) have been rotary-peeled and processed into boards with a phenol–resorcinol–formaldehyde adhesive to evaluate their performance under flexural, tensile, and compressive loads. Satisfactory coefficients of determination were reached for Norway spruce in regard to the silvicultural framework and the tree characteristics of slenderness and crown base height. Douglas fir products did not achieve comparable determination due to high variance within boards and stands but did achieve significantly better mechanical properties. Norway spruce was observed to be more responsive to thinning measures, while the effect of different thinning regimes was not evident for Douglas fir. The on-site evaluation of Douglas fir stands for veneer product quality based on silvicultural parameters and tree characteristics was shown to be inconclusive, with its naturally higher wood density being the decisive constant. Full article

Sluices play a critical role in flood control, power generation, water supply, etc. With decades of service, sluice safety assurance becomes a structural engineering imperative. Previous investigations have revealed that failures of sluices are often associated with seepage damage. To gain further insight into sluice seepage and ensure the safety of sluice structures, proposing an effective prediction method for sluice seepage nevertheless remains a challenging fundamental and practical perspective. Therefore, in this paper, a novel prediction model for sluice seepage based on impact factor screening methods, the improved Kepler optimization algorithm (IKOA) and the bidirectional gated recurrent unit (BiGRU), is presented. Primarily, the maximal information coefficient and the correlation-based feature selection (MIC–CFS) are introduced to screen the impact factors of the model, aiming to reduce redundant information and the complexity of the model. Subsequently, the Kepler optimization algorithm (KOA) is enhanced using three strategies: chaotic mapping-based initialization, Runge–Kutta-based position updating, and the enhanced solution quality (ESQ) strategy to optimize the hyperparameters of the BiGRU network. On this basis, the prediction model is established, which is applied in the Bengbu sluice to verify its fitting and prediction performance. Eventually, comparison analyses with a traditional stepwise regression model, IKOA–LSTM, and IKOA–GRU, were conducted based on monitoring sequences of three monitoring points. The coefficients of determination of the proposed model were located in the range of 0.974 to 0.988. Correspondingly, the mean absolute error values of the proposed model were the lowest, ranging from 0.074 to 0.064. The results of six evaluation metrics confirm that the proposed model consistently exhibits superior interpretability and is able to serve as a promising tool for sluice seepage prediction. Full article

Enhanced or engineered geothermal systems (EGSs), or non-hydrothermal resources, are highly notable among sustainable energy resources because of their abundance and cleanness. The EGS concept has received worldwide attention and undergone intensive studies in the last decade in the US and around the world. In comparison, hydrothermal reservoir resources, the ‘low-hanging fruit’ of geothermal energy, are very limited in amount or availability, while EGSs are extensive and have great potential to supply the entire world with the needed energy almost permanently. The EGS, in essence, is an engineered subsurface heat mining concept, where water or another suitable heat exchange fluid is injected into hot formations to extract heat from the hot dry rock (HDR). Specifically, the EGS relies on the principle that injected water, or another working fluid, penetrates deep into reservoirs through fractures or high-permeability channels to absorb large quantities of thermal energy by contact with the host hot rock. Finally, the heated fluid is produced through production wells for electricity generation or other usages. Heat mining from fractured EGS reservoirs is subject to complex interactions within the reservoir rock, involving high-temperature heat exchange, multi-phase flow, rock deformation, and chemical reactions under thermal-hydrological-mechanical (THM) processes or thermal-hydrological-mechanical-chemical (THMC) interactions. In this paper, we will present a THM model and reservoir simulator and its application for simulation of hydrothermal geothermal systems and EGS reservoirs as well as a methodology of coupling thermal, hydrological, and mechanical processes. A numerical approach, based on discretizing the thermo-poro-elastic Navier equation using an integral finite difference method, is discussed. This method provides a rigorous, accurate, and efficient fully coupled methodology for the three (THM) strongly interacted processes. Several programs based on this methodology are demonstrated in the simulation cases of geothermal reservoirs, including fracture aperture enhancement, thermal stress impact, and tracer transport in a field-scale reservoir. Results are displayed to show geomechanics’ impact on fluid and heat flow in geothermal reservoirs. Full article

Microplastic (MP) contamination affects all environmental media, even in remote, unpopulated regions of the globe. Many studies have addressed this issue under various aspects; however, actual and definitive evidence that MPs are a cause of human health risk in actual environmental conditions has not been provided. MP decomposition generates smaller nanoplastics (NPs) with different properties, closer to engineered nanoparticles than to MP. Their detection is more complex and laborious than MP’s, and, as such, their fate and effects are still poorly studied. Advanced technologies to remove MP/NPs from supply water are being investigated, but current evidence indicates that conventional drinking water treatment facilities efficiently remove a major part of MPs, at least as far as sizes greater than 20 µm. Notwithstanding recent developments in MP/NP classification and detection techniques, at the moment, very few studies specifically address NPs, which, therefore, deserve more targeted investigation. This paper addresses MPs and NPs in drinking water, examining recent current literature on their presence and state-of-the-art in risk assessment and toxicology. The paper also critically overviews treatment technologies for their removal and discusses the present knowledge gap and possible approaches to this widespread issue. Full article

With the high penetration of renewable energy, the imbalance between heat supply and demand is becoming increasingly severe. Installing additional heat storage bypass pipelines in the heating network can significantly enhance the heat storage capacity of the system, and regulating the supply and demand balance of heat stations can achieve a stable heat supply for users. This paper proposes a heat storage bypass configuration scheme and a dual-valve-coordinated control system. Based on the control valves’ ideal and operational flow characteristics, this paper delves into the minimum and maximum control impedance mechanisms in control valves, analyzing their impact on operational performance. Aiming at the fluctuation in the water supply temperature in the secondary pipe network (dead zone of 1%), the influence of control valve parameters on the dynamic response was systematically analyzed. The optimal parameter-matching scheme of the bypass control valve and the heat exchange control valve was finally determined through an optimization analysis. We verified its correctness based on the measured engineering data. This study improves the stability and operational efficiency of the supply and demand balance and decoupling control of the heating heat exchange unit, thereby establishing a critical technical foundation for advancing the high-efficiency integration of renewable energy sources within urban energy systems. Full article

The reduction of harmful emissions is shaping trends across many industries, including architecture and building. With rising ecological awareness and the threat of climate change, architects, construction engineers, and developers are focusing on innovative solutions to minimize the construction sector’s environmental impact. This paper presents a technical and management approach system using renewable energy sources, based on an existing single-family house with known energy consumption. The aim is to achieve energy independence by relying solely on on-site electricity generation and storage, while remaining connected to water and sewage infrastructure. Utilizing renewable energy sources enhances self-sufficiency and investment profitability. The study evaluates the house’s energy consumption to optimally select electricity supply solutions, including a small wind farm and photovoltaic installation integrated with appropriate electricity storage. This is crucial due to the air heat pump used for heating and domestic hot water, which requires electricity. An hourly simulation of the system’s operation over a year verified the adequacy of the selected devices. Additionally, two different locations were analyzed to assess how varying climate and wind conditions influence the design and performance of off-grid energy systems. The analysis showed that solar and wind systems can meet annual energy demand, but limited storage capacity prevents full autonomy. Replacing the heat pump with a biomass boiler reduces electricity use by about 25% and battery needs by 40%, though seasonal energy surpluses remain a challenge. This concept aligns with the goal of achieving climate neutrality by 2050. Full article

Dewpoint indirect evaporative cooling (DIEC) offers an energy-efficient, eco-friendly alternative to conventional air conditioning by using water and air to lower temperatures. With the rising demand for sustainable cooling solutions—especially in regions facing water scarcity and high energy costs—optimizing these systems for real-world conditions is more important than ever. One major challenge is ensuring that DIEC systems perform well when water is supplied intermittently rather than continuously. In this review, we examine how intermittent water supply affects the cooling performance and overall efficiency of DIEC systems. We discuss recent studies that highlight the importance of key factors such as the properties of heat exchanger materials, design modifications, and control strategies. Our analysis reveals that while innovative materials like hydrophilic membranes and adaptive design features can improve performance, their widespread use is often limited by cost and scalability. We also point out critical research gaps, particularly in applying intermittent water spraying to non-porous heat exchangers. Overall, our findings underscore the need for integrated water management strategies in DIEC design. We advocate a cross-disciplinary approach—bridging fluid dynamics, material science, and environmental engineering—to develop more resilient and sustainable cooling technologies. Full article

To address the challenges of environmental adaptability and passivation in nanoscale zero-valent iron (nFe⁰) systems, we developed oxalate-modified nFe⁰ (nFe_oxa) through a coordination-driven synthesis strategy, aiming to achieve high-efficiency Cr(VI) removal with improved stability and reusability. Structural characterization (STEM and FT-IR) confirmed the formation of a FeC₂O₄/nFe⁰ heterostructure, where oxalate coordinated with Fe(II) to construct a semiconductor interface that effectively inhibits anoxic passivation while enabling continuous electron supply, achieving 100% Cr(VI) removal efficiency within 20 min at an optimal oxalate/Fe molar ratio of 1/29. Mechanistic studies revealed that the oxalate ligand accelerates electron transfer from the Fe⁰ core to the surface via the FeC₂O₄-mediated pathway, as evidenced by EIS and LSV test analyses. This process dynamically regenerates surface Fe(II) active sites rather than relying on static-free Fe(II) adsorption. XPS and STEM further demonstrated that Cr(VI) was reduced to Cr(III) and uniformly co-precipitated with Fe(II/III)-oxalate complexes, effectively immobilizing chromium. The synergy between the protective semiconductor layer and the ligand-enhanced electron transfer endows nFe_oxa with superior reactivity. This work provides a ligand-engineering strategy to design robust nFe⁰-based materials for sustainable remediation of metal oxyanion-contaminated water. Full article

Albumin is the most abundant plasma protein, accounting for approximately 50% of total serum protein in healthy individuals. In recent years, albumin has attracted significant attention due to its biocompatibility, non-toxicity (metabolizing in vivo into harmless degradation products), non-immunogenic properties, ease of purification, and water solubility. These characteristics render it an ideal candidate for a wide range of biomedical applications. Its uses include drug delivery systems, wound healing, antioxidant therapies, infusion treatments, COVID-19 therapeutics, tissue engineering, and other critical care domains. Consequently, the global demand for albumin has been steadily increasing. The international albumin market was valued at USD 5394.9 million in 2021 and is projected to reach USD 9192 million by 2030, with a compound annual growth rate (CAGR) of 6.1%. Given its diverse applications and rising demand, substantial efforts have been made to ensure a sustainable supply of albumin. This review provides an overview of albumin, along with its novel applications, purification methods, and market trends. Full article