Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (3,139)

Search Parameters:
Keywords = first law

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
8 pages, 1353 KB  
Communication
Plant Cuticles Exhibit Significant Mid-Infrared Emissivity in the Atmospheric Windows
by Antonio Heredia, Ana González-Moreno, José J. Benítez and Eva Domínguez
Int. J. Mol. Sci. 2025, 26(20), 9917; https://doi.org/10.3390/ijms26209917 (registering DOI) - 12 Oct 2025
Abstract
As sessile organisms, plants have developed strategies to cope with exposure to high radiation. The plant cuticle is located at the interface between the plant and the surrounding environment, thus acting as a first barrier that protects plants against environmental conditions, including solar [...] Read more.
As sessile organisms, plants have developed strategies to cope with exposure to high radiation. The plant cuticle is located at the interface between the plant and the surrounding environment, thus acting as a first barrier that protects plants against environmental conditions, including solar radiation. The isolated cuticles displayed notable absorptance in the infrared spectral range which, according to Kirchhoff’s law of thermal radiation, equals the emission dissipation ability. Comparison among the different cuticles showed that a significant range of their reflectance, transmittance, and absorbance spectra match the spectral regions known as atmospheric windows, between 3–4 and 8–13 microns, located within the mid-infrared region (MIR). They allow energy to pass through into the outer space. These optical parameters varied between cuticles from different plant species and they were not a simple function of the cuticle’s thickness but the product of its specific composition in combination with its molecular arrangement. Full article
(This article belongs to the Special Issue Advanced Spectroscopy Research: New Findings and Perspectives)
Show Figures

Figure 1

21 pages, 266 KB  
Article
Law, Gender Justice, and the Dynamics of Democratic Backsliding
by Reut Itzkovitch-Malka
Laws 2025, 14(5), 77; https://doi.org/10.3390/laws14050077 (registering DOI) - 12 Oct 2025
Abstract
This paper examines democratic backsliding through the lens of gender justice, focusing on recent political developments in Israel. Since early 2023, the ruling coalition has advanced a judicial overhaul designed to reduce judicial independence and consolidate executive control. These changes should be understood [...] Read more.
This paper examines democratic backsliding through the lens of gender justice, focusing on recent political developments in Israel. Since early 2023, the ruling coalition has advanced a judicial overhaul designed to reduce judicial independence and consolidate executive control. These changes should be understood in tandem with a wave of suggested legislation targeting gender equality, women’s rights, and protections against discrimination in public life, education, and civil services. A qualitative analysis of governmental legislative initiatives reveals a troubling pattern: efforts to erode judicial independence are closely followed by laws that institutionalize gender segregation and undermine gender justice. This sequence reflects a deliberate strategy—first dismantling the legal safeguards, then attacking the rights they once protected. In response, women have played a leading role in Israel’s pro-democracy protest movement, using highly visible, gendered forms of resistance to signal that gender justice is a core democratic concern. The paper concludes that democratic backsliding in Israel is gendered in both its structure and its consequences, and any assessment of its impact must account for its disproportionate harm to women and marginalized communities. Full article
(This article belongs to the Special Issue Law and Gender Justice)
28 pages, 1072 KB  
Article
Does Green Finance Drive New Quality Productive Forces? Evidence from Chinese Listed Companies
by Purong Chen, Lei Nie, Shunfeng Song, Quan Sun and Jing Zhang
Sustainability 2025, 17(20), 8993; https://doi.org/10.3390/su17208993 (registering DOI) - 10 Oct 2025
Viewed by 110
Abstract
Productivity has long been the fundamental driver of human social progress and national prosperity. Against the backdrop of technological advancement and social development, New Quality Productive Forces (NQPFs) have emerged as a new form of productivity, serving as a key focus for corporate [...] Read more.
Productivity has long been the fundamental driver of human social progress and national prosperity. Against the backdrop of technological advancement and social development, New Quality Productive Forces (NQPFs) have emerged as a new form of productivity, serving as a key focus for corporate transformation and upgrading as well as sustainable national development. Based on the panel data of 28,107 listed companies in China from 2011 to 2022, this study employs a three-way fixed-effects model to investigate the impact of green finance (GF) on corporate NQPFs. The main findings are as follows: First, GF exhibits a significant positive correlation with the enhancement of corporate NQPFs. Second, financing constraints and corporate social responsibility strengthen the empowering effect of GF on corporate NQPFs, while environmental law enforcement weakens this effect, reflecting a “synergistic dilemma” between government intervention and market mechanisms in promoting corporate NQPFs. Third, the effect of GF on corporate NQPFs shows significant heterogeneity depending on environmental and social risks, the nature of property rights, public attention, and firm size. These findings provide important insights for optimizing green finance policies and enhancing corporate productivity. Full article
Show Figures

Figure 1

32 pages, 2350 KB  
Article
Heresy, Empire, and Authority: Muslim–Christian Interactions in Early Modern Ottoman Legal Thought and Critical Edition of Ibn Kemāl’s Treatise on Zindīq
by Abdullah Rıdvan Gökbel
Religions 2025, 16(10), 1284; https://doi.org/10.3390/rel16101284 - 9 Oct 2025
Viewed by 242
Abstract
In early modern Islamic thought, the concept of zindīq (heretic) occupied a critical space at the intersection of theology, law, and state authority, particularly in the context of Muslim–Christian relations. One of the most significant scholarly attempts to define this term came from [...] Read more.
In early modern Islamic thought, the concept of zindīq (heretic) occupied a critical space at the intersection of theology, law, and state authority, particularly in the context of Muslim–Christian relations. One of the most significant scholarly attempts to define this term came from Ibn Kemāl (d. 940/1534), a leading Ottoman jurist and theologian, whose treatise Risāla fī mā yataʿallaq bi-lafẓ al-zindīq (Treatise on the Definition of the Word Zindīq) sought to clarify the precise meaning and legal implications of zandaqa (heresy). This article provides the first English translation and critical edition of Ibn Kemāl’s treatise, making this important work accessible to a wider scholarly audience. Through a close reading of the text, this study examines how Ibn Kemāl systematically distinguished zindīq from murtadd (apostate), mulḥid (disbeliever), and munāfiq (hypocrite), shaping Ottoman legal discourse on heresy. The present analysis further explores the theological and jurisprudential foundations Ibn Kemāl employed to define and punish heretics, particularly in light of the controversial execution of Mollā Kābid (or Mullā Qābiḍ, tr. Molla Kābız), who had asserted the superiority of Jesus over Muhammad. This case demonstrates the presence of polemical debates in the shaping of confessional boundaries in the ninth/fifteenth-century Ottoman Empire and reflects the broader challenges of Muslim–Christian interactions during this period. Additionally, this study investigates the broader implications of Ibn Kemāl’s classification of zindīq within the context of Muslim–Christian relations, considering how interfaith polemics and religious boundary-making influenced Ottoman legal thought. By contextualizing this treatise within early modern Ottoman legal and theological traditions, this study contributes to the understanding of how heresy was redefined in a multi-religious empire navigating theological, political, and interreligious challenges. Full article
Show Figures

Figure A1

12 pages, 1308 KB  
Article
Pattern Synthesis for Uniform Linear and Concentric Elliptical Antenna Arrays Using Kepler Optimization Algorithm
by Yi Tang, Jiaxin Wan, Yixin Sun, Xiao Wang, Guoqing Ma and Chuan Liu
Symmetry 2025, 17(10), 1680; https://doi.org/10.3390/sym17101680 - 8 Oct 2025
Viewed by 161
Abstract
In this paper, a pattern synthesis method of uniform linear and concentric elliptical antenna arrays using the Kepler optimization algorithm (KOA) is proposed. The KOA, which utilizes Kepler’s laws to predict the position and velocity of planets at arbitrary times, is first applied [...] Read more.
In this paper, a pattern synthesis method of uniform linear and concentric elliptical antenna arrays using the Kepler optimization algorithm (KOA) is proposed. The KOA, which utilizes Kepler’s laws to predict the position and velocity of planets at arbitrary times, is first applied to deal with the optimization problems of linear and elliptical antenna arrays. Radiation patterns with high gain and low sidelobe levels (SLLs) are synthesized by optimizing the critical parameters (amplitude, phase, and rotation) of the linear arrays. Moreover, a concentric elliptical array is designed to demonstrate the capability of the KOA framework to solve complex problems and achieve the desired performance. In order to accurately consider mutual coupling between the elements, the full-wave method of moments (MoM) is used to calculate the radiation characteristics of the arrays in the optimization method. The effectiveness of the proposed method is proved by four typical examples. The results show that, compared with the butterfly optimization algorithm (BOA), Harris hawks optimization (HHO), and crayfish optimization algorithm (COA), the proposed method possesses high gain and SLL suppression capabilities, which makes it suitable for various array types. Full article
(This article belongs to the Section Engineering and Materials)
Show Figures

Figure 1

18 pages, 1311 KB  
Article
Thermo-Energetic Analysis of Electrolytic Oxygen Valorization via Biomass Oxy-Fuel Combustion: A Case Study Applied to a Power-to-Liquid Route for Methanol Synthesis
by Flávio S. Pereira, Argimiro R. Secchi and Alexandre Szklo
Thermo 2025, 5(4), 41; https://doi.org/10.3390/thermo5040041 - 7 Oct 2025
Viewed by 248
Abstract
The decarbonization of hard-to-defossilize sectors, such as international maritime transport, requires innovative, and at times disruptive, energy solutions that combine efficiency, scalability, and climate benefits. Therefore, power-to-liquid (PtL) routes have stood out for their potential to use low-emission electricity for the production of [...] Read more.
The decarbonization of hard-to-defossilize sectors, such as international maritime transport, requires innovative, and at times disruptive, energy solutions that combine efficiency, scalability, and climate benefits. Therefore, power-to-liquid (PtL) routes have stood out for their potential to use low-emission electricity for the production of synthetic fuels, via electrolytic hydrogen and CO2 capture. However, the high energy demand inherent to these routes poses significant challenges to large-scale implementation. Moreover, PtL routes are usually at most neutral in terms of CO2 emissions. This study evaluates, from a thermo-energetic perspective, the optimization potential of an e-methanol synthesis route through integration with a biomass oxy-fuel combustion process, making use of electrolytic oxygen as the oxidizing agent and the captured CO2 as the carbon source. From the standpoint of a first-law thermodynamic analysis, mass and energy balances were developed considering the full oxygen supply for oxy-fuel combustion to be met through alkaline electrolysis, thus eliminating the energy penalty associated with conventional oxygen production via air separation units. The balance closure was based on a small-scale plant with a capacity of around 100 kta of methanol. In this integrated configuration, additional CO2 surpluses beyond methanol synthesis demand can be directed to geological storage, which, when combined with bioenergy with carbon capture and storage (BECCS) strategies, may lead to net negative CO2 emissions. The results demonstrate that electrolytic oxygen valorization is a promising pathway to enhance the efficiency and climate performance of PtL processes. Full article
Show Figures

Figure 1

12 pages, 226 KB  
Article
Perceptions of Spectacle Use Among Undergraduate Students in Oman: Visual Symptoms, Convenience, and Disadvantages
by Janitha Plackal Ayyappan, Hilal Alrahbi, Gopi Vankudre, Zoelfigar Mohamed, Virgina Varghese and Sabitha Sadandan
Healthcare 2025, 13(19), 2525; https://doi.org/10.3390/healthcare13192525 - 6 Oct 2025
Viewed by 214
Abstract
Background: Globally, uncorrected refractive errors are recognized as the primary cause of visual impairment and blindness. According to a report by the World Health Organization (WHO), providing spectacle lenses at an affordable cost remains a significant challenge, particularly for underprivileged populations in developing [...] Read more.
Background: Globally, uncorrected refractive errors are recognized as the primary cause of visual impairment and blindness. According to a report by the World Health Organization (WHO), providing spectacle lenses at an affordable cost remains a significant challenge, particularly for underprivileged populations in developing countries. This challenge contributes to the low compliance with spectacle wear worldwide. However, the benefits of wearing spectacles are influenced by the perceptions of the population regarding spectacle use. Methods: A quantitative, cross-sectional survey-based study was conducted at a superior educative center in Oman, the University of Buraimi. Participants were recruited from the four major colleges, namely, the College of Health Sciences (COHS), College of Business (COB), College of Engineering (COE), and College of Law (COL), and the Center for Foundation Studies (CFS). This study was conducted over the period from 18 December 2022 to 18 December 2023. Essential data were collected using an electronic questionnaire facilitated by the Google platform. The initial section of the questionnaire outlines this study’s objectives and its benefits to the community. The digital survey comprises three sections: the first section addresses the sociodemographic profile of the participants; the second section explores perceptions related to spectacles; and the third section examines visual symptoms associated with spectacle wear. In this study, a pre-tested survey was administered following consultation with a panel of three subject matter experts who reviewed the clarity and content validity of the test items. Data analyses were performed using descriptive statistics, and linear regression was applied to assess the effect of socioeconomic profile on perceptions of spectacles. Additionally, data entry, processing, and analysis were conducted using SPSS 25 software. The overall mean score for spectacle-related visual symptoms was 2.51 ± 0.75, indicating a moderate level of symptom occurrence. Results: A total of 415 participants (N = 415) were included in this study, comprising 133 males (32.0%) and 282 females (68.0%). The most prominent symptoms related to spectacle perception were “light sensitivity” and “eye pain”, with mean values of 3.03 ± 1.30 and 3.04 ± 1.25, respectively. Additionally, 249 participants (60%) reported moderate concern regarding spectacle-related visual symptoms. Among female participants, 118 (41.8%) exhibited little concern about visual symptoms associated with spectacle wear, whereas this was observed in 25.6% of male participants. Descriptive statistics indicated the mean perceived spectacle-related disadvantages score measured on a scale of 0 to 4 was 2.88 ± 1.16 (57.69% ± 23.15% in percentages), reflecting a moderate perception of such disadvantages. The linear regression model demonstrated statistical significance, as indicated by the likelihood ratio chi-square = 199.194 (df = 15, p < 0.001). The most significant predictor was study major (χ2 = 72.922, p < 0.001). Conclusions: The present study indicates that undergraduate students generally exhibit a low perception of the disadvantages associated with wearing spectacles. Randomized sampling should be preferred in future studies to the convenience sampling technique. The most frequently reported visual symptoms include “light sensitivity and eye pain” among spectacle wearers. Therefore, it is imperative to implement health education programs and foundational studies across colleges to address these issues among undergraduate university students. Full article
(This article belongs to the Special Issue Advances in Primary Health Care and Community Health)
12 pages, 1012 KB  
Article
Diffraction by Circular Pin: Wiener–Hopf Method
by Seil Sautbekov, Merey Sautbekova and Gulnara Bairova
Mathematics 2025, 13(19), 3186; https://doi.org/10.3390/math13193186 - 4 Oct 2025
Viewed by 144
Abstract
In this paper, the boundary value problem of wave diffraction on a semi-infinite circular pin is solved using the Wiener–Hopf method with compensation of eigenmodes. The solution to the problem is presented as an infinite series defined by a recurrence formula. The reliability [...] Read more.
In this paper, the boundary value problem of wave diffraction on a semi-infinite circular pin is solved using the Wiener–Hopf method with compensation of eigenmodes. The solution to the problem is presented as an infinite series defined by a recurrence formula. The reliability and accuracy of the solution are verified numerically in terms of fulfillment of the law of energy conservation. Sufficiently reliable results are obtained at the first iteration. The method used for solving this problem can be applied to solving diffraction problems on axisymmetric volumetric structures. Full article
(This article belongs to the Special Issue Computational Methods in Electromagnetics)
Show Figures

Figure 1

13 pages, 2974 KB  
Article
The Mechanism of Casing Perforation Erosion Under Fracturing-Fluid Flow: An FSI and Strength Criteria Study
by Hui Zhang and Chengwen Wang
Modelling 2025, 6(4), 121; https://doi.org/10.3390/modelling6040121 - 4 Oct 2025
Viewed by 174
Abstract
High-pressure, high-volume fracturing in unconventional reservoirs often induces perforation erosion damage, endangering operational safety. This paper employs fluid–solid coupling theory to analyze the flow characteristics of fracturing fluid inside the casing during fracturing. Combined with strength theory, the stress distribution and variation law [...] Read more.
High-pressure, high-volume fracturing in unconventional reservoirs often induces perforation erosion damage, endangering operational safety. This paper employs fluid–solid coupling theory to analyze the flow characteristics of fracturing fluid inside the casing during fracturing. Combined with strength theory, the stress distribution and variation law are investigated, revealing the mechanical mechanism of casing perforation erosion damage. The results indicate that the structural discontinuity at the entrance of the perforation tunnel causes an increase in fracturing-fluid velocity, and this is where the most severe erosion happens. The stress around the perforation is symmetrically distributed along the perforation axis. The casing inner wall experiences a combined tensile–compressive stress state, while non-perforated regions are under pure tensile stress, with the maximum amplitudes occurring in the 90° and 270° directions. Although the tensile and compressive stress do not exceed the material’s allowable stress, the shear stress exceeds the allowable shear stress, indicating that shear stress failure is likely to initiate at the perforation, inducing erosion. Moreover, under the impact of fracturing fluid, the contact forces at the first and second interfaces of the casing are unevenly distributed, reducing cement bonding capability and compromising casing integrity. The findings provide a theoretical basis for optimizing casing selection. Full article
Show Figures

Figure 1

29 pages, 2052 KB  
Article
Comparison of Alternative Port-Hamiltonian Dynamics Extensions to the Thermodynamic Domain Toward IDA-PBC-Like Control: Application to a Heat Transfer Model
by Oleksiy Kuznyetsov
Dynamics 2025, 5(4), 42; https://doi.org/10.3390/dynamics5040042 - 1 Oct 2025
Viewed by 178
Abstract
The dynamics of port-Hamiltonian systems is based on energy balance principles (the first law of thermodynamics) embedded in the structure of the model. However, when dealing with thermodynamic subsystems, the second law (entropy production) should also be explicitly taken into account. Several frameworks [...] Read more.
The dynamics of port-Hamiltonian systems is based on energy balance principles (the first law of thermodynamics) embedded in the structure of the model. However, when dealing with thermodynamic subsystems, the second law (entropy production) should also be explicitly taken into account. Several frameworks were developed as extensions to the thermodynamic domain of port-Hamiltonian systems. In our work, we study three of them, namely irreversible port-Hamiltonian systems, entropy-based generalized Hamiltonian systems, and entropy-production-metric-based port-Hamiltonian systems, which represent alternative approaches of selecting the state variables, the storage function, simplicity of physical interpretation, etc. On the example of a simplified lumped-parameter model of a heat exchanger, we study the frameworks in terms of their implementability for an IDA-PBC-like control and the simplicity of using these frameworks for practitioners already familiar with the port-Hamiltonian systems. The comparative study demonstrated the possibility of using each of these approaches to derive IDA-PBC-like thermodynamically consistent control and provided insight into the applicability of each framework for the modeling and control of multiphysics systems with thermodynamic subsystems. Full article
Show Figures

Graphical abstract

16 pages, 296 KB  
Article
Nonlocal Internal Variable and Superfluid State in Liquid Helium II
by Vito Antonio Cimmelli
Mathematics 2025, 13(19), 3134; https://doi.org/10.3390/math13193134 - 1 Oct 2025
Viewed by 126
Abstract
We present a model of superfluidity based on the internal variable theory. We consider a two-component fluid endowed with a scalar internal variable whose gradient is the counterflow velocity. The restrictions imposed by the second law of thermodynamics are obtained by applying a [...] Read more.
We present a model of superfluidity based on the internal variable theory. We consider a two-component fluid endowed with a scalar internal variable whose gradient is the counterflow velocity. The restrictions imposed by the second law of thermodynamics are obtained by applying a generalized Coleman–Noll procedure. A set of constitutive equations of the Landau type, with entropy, entropy flux and stress tensor depending on the counterflow velocity, is obtained. The propagation of acceleration waves is investigated as well. It is shown that the first-and-second sound waves may propagate along the system with speeds depending on the physical parameters of the two fluids. First sound waves may propagate in the same direction or in the opposite direction of the counterflow velocity, depending on the concentration of normal and superfluid components. The speeds of second sound waves have the same mathematical form of those propagating in dielectric crystals. Full article
(This article belongs to the Section E4: Mathematical Physics)
25 pages, 26694 KB  
Article
Research on Wind Field Correction Method Integrating Position Information and Proxy Divergence
by Jianhong Gan, Mengjia Zhang, Cen Gao, Peiyang Wei, Zhibin Li and Chunjiang Wu
Biomimetics 2025, 10(10), 651; https://doi.org/10.3390/biomimetics10100651 - 1 Oct 2025
Viewed by 267
Abstract
The accuracy of numerical model outputs strongly depends on the quality of the initial wind field, yet ground observation data are typically sparse and provide incomplete spatial coverage. More importantly, many current mainstream correction models rely on reanalysis grid datasets like ERA5 as [...] Read more.
The accuracy of numerical model outputs strongly depends on the quality of the initial wind field, yet ground observation data are typically sparse and provide incomplete spatial coverage. More importantly, many current mainstream correction models rely on reanalysis grid datasets like ERA5 as the true value, which relies on interpolation calculation, which directly affects the accuracy of the correction results. To address these issues, we propose a new deep learning model, PPWNet. The model directly uses sparse and discretely distributed observation data as the true value, which integrates observation point positions and a physical consistency term to achieve a high-precision corrected wind field. The model design is inspired by biological intelligence. First, observation point positions are encoded as input and observation values are included in the loss function. Second, a parallel dual-branch DenseInception network is employed to extract multi-scale grid features, simulating the hierarchical processing of the biological visual system. Meanwhile, PPWNet references the PointNet architecture and introduces an attention mechanism to efficiently extract features from sparse and irregular observation positions. This mechanism reflects the selective focus of cognitive functions. Furthermore, this paper incorporates physical knowledge into the model optimization process by adding a learned physical consistency term to the loss function, ensuring that the corrected results not only approximate the observations but also adhere to physical laws. Finally, hyperparameters are automatically tuned using the Bayesian TPE algorithm. Experiments demonstrate that PPWNet outperforms both traditional and existing deep learning methods. It reduces the MAE by 38.65% and the RMSE by 28.93%. The corrected wind field shows better agreement with observations in both wind speed and direction, confirming the effectiveness of incorporating position information and a physics-informed approach into deep learning-based wind field correction. Full article
(This article belongs to the Special Issue Nature-Inspired Metaheuristic Optimization Algorithms 2025)
Show Figures

Figure 1

27 pages, 8152 KB  
Article
Experimental Study on the Degradation Mechanism of BFRP Under the Coupling Effect of Chloride Freeze-Thaw Cycles
by Zhigang Gao, Tao He, Qing Qin, Chenghua Zhang, Zhe Wang, Qi Lin and Yuhao Hei
Polymers 2025, 17(19), 2654; https://doi.org/10.3390/polym17192654 - 30 Sep 2025
Viewed by 162
Abstract
Basalt fiber reinforced polymer (BFRP) is one of the new materials that can be used for making photovoltaic scaffolds, which can effectively solve the problem of the rapid deterioration of complex environmental performance and high maintenance cost of traditional scaffold materials. This paper [...] Read more.
Basalt fiber reinforced polymer (BFRP) is one of the new materials that can be used for making photovoltaic scaffolds, which can effectively solve the problem of the rapid deterioration of complex environmental performance and high maintenance cost of traditional scaffold materials. This paper focuses on the BFRP photovoltaic support in the cold and arid irrigation area of northwest China, carries out the durability test under the action of chloride salt, freeze-thaw cycle, and chloride salt freeze-thaw environment coupling, and it compares and analyzes the degradation law of the mechanical properties of BFRP sheets under different environmental effects. The performance degradation mechanism of BFRP materials under different environmental effects was revealed by SEM scanning electron microscopy and EDS energy spectrum analysis. The main conclusions are as follows: (1) Under the action of chloride salt, the tensile strength, elastic modulus and elongation at break of the specimen decreased by 11.46%, 7.02%, and 10.27%, respectively. Under the freeze-thaw cycle, the tensile strength and elongation at break of the specimen decreased by 9.62% and 6.85%, while the elastic modulus first increased and then decreased, with a maximum decrease of 12.95%. The degradation of mechanical properties is the most serious under the coupling effect of chloride salt and the freeze-thaw environment. The tensile strength, elastic modulus, and elongation at break of the specimens decreased by 25.73%, 9.55%, and 24.81%, respectively. (2) In the chloride environment, the distribution of elements on the surface of the specimen changed, the metal ions of the fibers precipitated, and ‘black spots‘ and corrosion pits appeared. The resin matrix forms ‘sponge-like‘ pores; under the freeze-thaw cycle, the fiber–resin interface cracks and fiber shedding intensifies; under the coupling effect of chloride freeze-thaw, ‘black spots‘, pits, resin holes, and interface cracks increased, and chloride penetration corrosion accelerated. Full article
(This article belongs to the Section Polymer Composites and Nanocomposites)
Show Figures

Graphical abstract

11 pages, 1765 KB  
Article
Viscosity Analysis of Electron-Beam Degraded Gellan in Dilute Aqueous Solution
by Fathi Elashhab, Lobna Sheha, Nada Elzawi and Abdelsallam E. A. Youssef
Physchem 2025, 5(4), 40; https://doi.org/10.3390/physchem5040040 - 30 Sep 2025
Viewed by 209
Abstract
Gellan gum (Gellan), a versatile polysaccharide applied in gel formation and prebiotic formulations, is often processed to tailor its molecular properties. Previous studies employed gamma irradiation and chemical hydrolysis, though without addressing systematic scaling behavior. This study investigates the structural and conformational modifications [...] Read more.
Gellan gum (Gellan), a versatile polysaccharide applied in gel formation and prebiotic formulations, is often processed to tailor its molecular properties. Previous studies employed gamma irradiation and chemical hydrolysis, though without addressing systematic scaling behavior. This study investigates the structural and conformational modifications of Gellan in dilute aqueous salt solutions using a safer and eco-friendly approach: atmospheric low-dose electron beam (e-beam) degradation coupled with viscosity analysis. Native and E-beam-treated Gellan samples (0.05 g/cm3 in 0.1 M KCl) were examined by relative viscosity at varying temperatures, with intrinsic viscosity and molar mass determined via Solomon–Ciuta and Mark–Houwink relations. Molar mass degradation followed first-order kinetics, yielding rate constants and degradation lifetimes. Structural parameters, including radius of gyration and second virial coefficient, produced scaling coefficients of 0.62 and 0.15, consistent with perturbed coil conformations in a good solvent. The shape factor confirmed preservation of an ideal random coil structure despite irradiation. Conformational flexibility was further analyzed using theoretical models. Transition state theory (TST) revealed that e-beam radiation lowered molar mass and activation energy but raised activation entropy, implying reduced flexibility alongside enhanced solvent interactions. The freely rotating chain (FRC) model estimated end-to-end distance (Rθ) and characteristic ratio (C), while the worm-like chain (WLC) model quantified persistence length (lp). Results indicated decreased Rθ, increased lp, and largely unchanged C, suggesting diminished chain flexibility without significant deviation from ideal coil behavior. Overall, this work provides new insights into Gellan’s scaling laws and flexibility under aerobic low-dose E-beam irradiation, with relevance for bioactive polysaccharide applications. Full article
(This article belongs to the Section Theoretical and Computational Chemistry)
Show Figures

Figure 1

19 pages, 2933 KB  
Article
Experimental Study on Wettability Characteristics of Falling Film Flow Outside Multi-Row Horizontal Tubes
by Zhenchuan Wang and Meijun Li
Processes 2025, 13(10), 3119; https://doi.org/10.3390/pr13103119 - 29 Sep 2025
Viewed by 278
Abstract
The wettability of falling film flow outside multi-row horizontal tubes is a core factor determining the heat and mass transfer performance of falling film heat exchangers, which is critical for their optimized design and stable operation. A visualization experimental platform for falling film [...] Read more.
The wettability of falling film flow outside multi-row horizontal tubes is a core factor determining the heat and mass transfer performance of falling film heat exchangers, which is critical for their optimized design and stable operation. A visualization experimental platform for falling film flow over ten rows of horizontal tubes was constructed, with water as the working fluid. High-definition imaging technology and image processing methods were employed to systematically investigate the liquid film distribution and wettability under three tube diameters (d = 0.016, 0.019, 0.025 m), four tube spacings (s = 0.75d, 1d, 1.25d, 1.5d), and four inter-tube flow patterns (droplet, columnar, column-sheet, and sheet flow). Two parameters, namely the “total wetting length” and the “total wetting area”, were proposed and defined. The distribution characteristics of the wetting ratio for each row of tubes were analyzed, along with the variation laws of the total wetting area of the ten rows of tubes with respect to tube diameter, tube spacing, and liquid film Reynolds number (Rel). The following results were indicated: (1) Increasing the fluid flow rate and the tube spacing both promote the growth of the wetting length. When Rel ≤ 505, with the increase of tube diameter, the percentage of the wetting length of the tenth tube row relative to that of the first tube row decreases under the same fluid flow rate; when Rel > 505, this percentage first decreases and then increases. (2) The total wetting area exhibits a trend of “first increasing then decreasing” or “continuous increasing” with the tube spacing, and the optimal tube spacing varies by flow pattern: s/d = 1 for droplet flow (d ≤ 0.016 m), s/d = 1.25 for columnar flow, and s/d = 1.25 (0.016 m), 1 (0.019 m), 1.5 (0.025 m) for sheet flow. (3) The effect of tube diameter on the total wetting area is a balance between the inhibitory effect (reduced inter-tube fluid dynamic potential energy) and promotional effect (thinner liquid film spreading). The optimal tube diameter is 0.016 m for droplet flow and 0.025 m for columnar/sheet flow (at s/d = 1.25). (4) The wetting performance follows the order 0.016 m > 0.025 m > 0.019 m when Rel > 505, and 0.025 m > 0.019 m > 0.016 m when Rel ≤ 505. Finally, an experimental correlation formula for the wetting ratio considering the Rel, the tube diameter, and tube spacing was fitted. Comparisons with the present experimental data, the literature simulation results, and the literature experimental data showed average errors of ≤10%, ≤8%, and ≤14%, respectively, indicating high prediction accuracy. This study provides quantitative data and theoretical support for the structural optimization and operation control of multi-row horizontal tube falling film heat exchangers. Full article
(This article belongs to the Section Energy Systems)
Show Figures

Figure 1

Back to TopTop