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Pattern-free, Thermally Stable, Broadband ZrN/GZO Metasurface Solar Absorber for High Temperature Applications
No full textThis work presents a wideband, thermally stable, and high-emissivity solar absorber to operate under the high-temperature conditions. The periodic nanostructure of the device comprises square-shaped stacking layers made of high-temperature materials GZO and ZrN deposited on a SiO2 substrate backed with a tungsten (W) reflecting layer. The developed device exhibits a total emissivity of greater than 90% across the wavelength range of 400 to 2400 nm and thermal radiation efficiency of 94% at 1500°C. The proposed structure has demonstrated exceptional performance at high-temperature operating conditions as a thermal emitter. Besides that, the proposed device shows excellent solar energy capturing ability, exhibits its solar spectra, and shows a nearly perfect match with the standard solar AM 1.5 model that makes it potentially useful for solar cell-based applications. Furthermore, the physics behind the high percentage of solar energy absorption in the structure was analyzed in terms of the surface electric field at selective wavelengths. Additionally, the proposed structure is insensitive to the polarization of the light due to its symmetric structure. Furthermore, it shows wide angular stability, which makes the proposed emitter useful for industrial applications such as seawater distillation, water distillation in remote areas, energy storage, and thermal applications, including solar photovoltaic-thermal (SPVT) systems
Assessment of Bottom Trawl Impacts on the Status of Seabed Communities in European Seas
No full textBottom trawling affects seabed habitats, but its large-scale impacts remain poorly quantified. Assessment of trawling impacts is essential to support monitoring and achieving sustainability objectives under international conventions, sustainable development goals, and seafood certification programs. We present a Europe-wide quantitative assessment of bottom trawling impacts, accounting for regional seabed-community sensitivity drivers, across the Baltic, Atlantic, Mediterranean and Black Sea continental shelves. Using two risk-based indicators of seabed status—Relative Benthic Status determined as benthic community biomass relative to seabed fauna carrying capacity (RBStot) and RBSsen (biomass of the 10% most sensitive fauna relative to carrying capacity)—we found substantial regional and habitat differences. The Black, Baltic and Aegean-Levantine Seas showed low trawling intensity and high seabed status across habitats. In contrast, the Western Mediterranean, Ionian and Central Mediterranean and Adriatic Seas were the most severely impacted. Trawling affected the sensitive species biomass fraction more strongly than the total community biomass. RBStot was in good condition (here chosen as RBS > 75% for epifauna) for over 79% of habitat-ecoregion combinations. In contrast, RBSsen met this threshold in only 46% of these. A strong correlation emerged between the mean trawling intensity and RBStot and RBSsen, allowing the use of SAR to estimate ecosystem status. This relationship can support decisions on where, and by how much, SAR reductions are needed to achieve good environmental status in regions where no detailed assessment is available. Our approach provides a quantitative framework to balance fishery production with ecosystem sustainability, offering tools for environmental and fisheries management in Europe.</p
Systematic synthesis and crystallographic characterisation of p-tert-butylcalix[4]arene derivatives bearing linear, achiral branched, and guerbet-type substituents
No full textA systematic series of p-tert-butylcalix[4]arene derivatives bearing linear, achiral branched and Guerbet-type branched hydrocarbons at the lower rim were synthesised via Williamson etherification. Sodium hydride yielded tetra-substituted products, while potassium carbonate produced 1,3-di-substituted derivatives. All compounds were characterised by NMR, FTIR, and mass spectrometry.. Single crystals were obtained from tetra-O-alkylated derivatives with n-dodecyl, n-tetradecyl and 2-ethylbutyl hydrocarbon chains; Guerbet-type derivatives remained viscous oils, reflecting the inability of racemic β-branched architectures to crystallise. X-ray diffraction revealed invariant calix[4]arene core geometries but distinct supramolecular packing: linear chains form head-to-head bilayers through interdigitation, while 2-ethylbutyl disrupts bilayer packing, adopting staggered arrangements stabilised by C–H···π contacts. The 2-ethylbutyl derivative represents the first crystallographic characterisation of any branched-alkyl calix[4]arene, demonstrating that substituent topology fundamentally alters supramolecular organisation
Assessment of Bottom Trawl Impacts on the Status of Seabed Communities in European Seas
No full textBottom trawling affects seabed habitats, but its large-scale impacts remain poorly quantified. Assessment of trawling impacts is essential to support monitoring and achieving sustainability objectives under international conventions, sustainable development goals, and seafood certification programs. We present a Europe-wide quantitative assessment of bottom trawling impacts, accounting for regional seabed-community sensitivity drivers, across the Baltic, Atlantic, Mediterranean and Black Sea continental shelves. Using two risk-based indicators of seabed status—Relative Benthic Status determined as benthic community biomass relative to seabed fauna carrying capacity (RBStot) and RBSsen (biomass of the 10% most sensitive fauna relative to carrying capacity)—we found substantial regional and habitat differences. The Black, Baltic and Aegean-Levantine Seas showed low trawling intensity and high seabed status across habitats. In contrast, the Western Mediterranean, Ionian and Central Mediterranean and Adriatic Seas were the most severely impacted. Trawling affected the sensitive species biomass fraction more strongly than the total community biomass. RBStot was in good condition (here chosen as RBS > 75% for epifauna) for over 79% of habitat-ecoregion combinations. In contrast, RBSsen met this threshold in only 46% of these. A strong correlation emerged between the mean trawling intensity and RBStot and RBSsen, allowing the use of SAR to estimate ecosystem status. This relationship can support decisions on where, and by how much, SAR reductions are needed to achieve good environmental status in regions where no detailed assessment is available. Our approach provides a quantitative framework to balance fishery production with ecosystem sustainability, offering tools for environmental and fisheries management in Europe.</p
Closed-form Harmonic Contrast Control with Surface Impedance Coatings for Conductive Objects
No full textThe problem of suppressing the scattering from conductive objects is addressed in terms of contrast reduction. A unique compact closed-form solution for a surface impedance Zs(m, kr) is found in a straightforward manner and without any approximation as a function of the harmonic index m (scattering mode to suppress) and of the frequency regime kr (product of wavenumber k and radius r of the cloaked system) at any frequency regime. In the quasi-static limit, mantle cloaking is obtained as a particular case for kr << 1 and m = 0. In addition, beyond quasi-static regime, impedance coatings for a selected dominant harmonic wave can be build with their proper dispersive behaviour, resulting in improved reduction levels and harmonic filtering capability
Tunable Narrow Bandwidth of a Bandpass Filter combined Microstrip and Suspended substrate stripline
No full textThis paper introduces a narrow bandwidth tunable filter. The filter has been tuned electronically by using varactor diodes. A set of mechanically tuning screws have been utilized to overcome the manufacturing tolerance of the filter's resonators. In contrast to most the combline filters, which depend on the cross‐coupling approach to generate the transmission poles, the proposed filter has a pair of transmission zeros located on both sides of the passband, by employing two uncoupled microstrip resonators that have been electronically tuned independently. The proposed filter bandwidth tuning range is 59–88 MHz with 3 dB fractional bandwidth 1.94–2.76 respectively. A detailed demonstration of the suggested tunable filter is introduced based on a mathematical approach
Do Predictors of Life Satisfaction Change in the Last Years Leading Up to Retirement? The Case of Job Satisfaction and Leisure Satisfaction
No full textBackgroundPredictors of life satisfaction vary between people of different ages, but little is known about the role of specific life phases. We focused on the last years of work before retirement when it is often assumed that workers become less attached to their workplace and focus on other areas of life instead, such as leisure activity. Our aim was to test if the associations between domain satisfaction (job and leisure) and overall life satisfaction change in the years before retirement.MethodsWe applied a time-to-retirement metric in a latent growth curve analysis to longitudinal data from the German Socioeconomic Panel Study (n = 2520) to investigate whether the within-person associations between (1) job and overall life satisfaction and (2) leisure and overall life satisfaction change in the 10 years preceding retirement.ResultsWe found that job satisfaction was positively associated with life satisfaction at the between-and within-person level, but the within-person association weakened as workers approached retirement. The positive within-person association between leisure and life satisfaction did not change significantly on the lead up to retirement.ConclusionsWe interpret the results as evidence for a potential preretirement work disengagement, either to support postretirement adjustment or to protect from negative work experiences, in line with lifespan theories on self-regulation
Glocalization of consumer culture: An emerging pattern in the post-globalized world
No full textPurpose: The paper examines the complex and often contradictory nature of consumer identity and consumption patterns within our contemporary landscape, shaped by post-globalization processes and geopolitical consequences. It delves into the implications of this dynamic environment for marketing strategies, highlighting the depth and complexity of consumer behavior in an era characterized by constant connectivity and curated digital experiences.Design/methodology/approach: This conceptual paper builds upon the emerging body of literature in consumer studies, international marketing, international business, information systems and general management. Findings: We reconceptualize the glocalization of consumer culture, in light of a newly developed concept - post-global consumer culture - by critically analyzing scholarly works and industry reports. Originality: We have developed the concept of a post-global consumer culture, which is grounded in a complex typology of political identity and digital consumer culture. Additionally, we have reconceptualized the glocalization of consumer culture, considering the dynamic and evolving nature of today’s world. Practical implications: The paper offers useful insights into why and how post-globalized consumers vary in terms of their attitude toward global and local brands. Accordingly, international marketers can develop useful segmentation and positioning strategies
Broadband high-temperature metamaterial absorber and thermal emitter composed of fractal geometry
No full textFractal structures are natural patterns that repeat themselves. They have several unique features that make them ideal for solar energy absorption and sensing applications. In this study, we present a high-performance, polarization insensitive solar absorber comprises of a nickel (Ni)-made hash-shaped fractal geometry develop over a thin layer of gallium-doped zinc oxide (GZO) features a high absorption rate that covers the visible and near-infrared wavelengths of the spectrum. The results show that broadband aggregative absorptivity of 92% is attained between 380 nm and 3850 nm attributed to remarkable localized surface plasmon resonance (LSPR) induced by the periodic array of Ni nano-resonators and surface plasmon resonance (SPR) at the interface of GZO-SiO2 layers. Further, the absorptivity remains above 90% from 670 nm to 3850 nm over a bandwidth of 3180 nm. With the utility of high-temperature resilient materials in the developed metamaterial structure, it shows potential for the thermal applications; as the results indicate the maximum heat radiation efficiency is 92.88% at 1600 K. Aside from that, we provide insight into the broadband high solar light capturing characteristics of the proposed device with the support of surface current density and electric field distribution study at the selective wavelengths. Furthermore, the device’s parametric study revealed a minor impact on its absorptivity/emissivity characteristics while also suggesting its robustness, which could be useful in device manufacture process. The overall benefits of the proposed device show its potential for high-temperature solar energy harvesting applications and solar thermophotovoltaic (STPV) cells.</p
Effect of belite-rich cement on the micro/macro properties and sustainability of slag–oyster powder–cement-based ternary materials
No full textAgainst the backdrop of global urbanization, the production of cement materials continues to increase. The need to meet development needs also raises concerns about environmental pollution. The cement industry is confronting an increasingly serious challenge of reducing carbon emissions. Using supplementary cementitious materials to replace part of the cement is a direct way to reduce carbon dioxide emissions. In this study, ternary blended cement (TBC) was prepared using blast furnace slag (BFS), oyster powder (OSP), and belite-rich cement on the micro/macroscale, and ternary slag–oyster powder–cement-based materials were prepared by partially or completely replacing the Ordinary Portland cement (OPC) in TBC with more environmentally belite-rich cement (BRC).The surface resistivity, and ultrasonic pulse velocity (UPV), mechanical properties of the hybrid samples were assessed through macroscopic experiments. Microscopic characterization of the samples included heat of hydration, thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Finally, the sustainability of CO2 emissions per unit volume and strength of the mixed samples was assessed. The results indicate that substituting BRC for OPC can effectively reduce the cumulative hydration heat and surface resistivity of the mixed sample. At 90 d, a BRC substitution ratio of one-third yields the highest compressive strength, while complete replacement results in the lowest compressive strength. BRC substitution decreases the CO2 emissions per unit volume of the mixed sample. The lowest CO2 emissions per unit strength occur with a one-third BRC replacement ratio, which is identified as the optimal substitution level
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