Effective Medium Research Articles

Control of the near-field radiative heat transfer between graphene-coated nanoparticle metasurfaces

The control of near-field radiative heat transfer (NFRHT) between two metasurfaces can be achieved by manipulating the geometric and dielectric parameters of their components. Based on a 2D effective medium approximation, we describe the dielectric response of each metasurface composed of graphene-coated nanoparticles (GCNPs) on a 2D square lattice as a homogeneous uniaxial film. Wrapping Drude-like nanoparticles (NPs) with graphene enhances the effective plasmonic response of metasurfaces by significantly broadening the frequency range in which surface and hyperbolic waves can be excited by thermal photons. Consequently, the NFRHT between GCNP metasurfaces improves that observed between uncoated Drude-like nanoparticle arrays. We found that the heat flux (Q) grows with increasing metasurface packing fraction (PF) and is also sensitive to GCNP size. By tuning the graphene chemical potential (μ)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(\\mu )$$\\end{document}, Q reaches a maximum improvement of 88%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$88\\%$$\\end{document} for μ≈0.1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mu \\approx 0.1$$\\end{document} eV with cores made of Drude-like material, while using cores made of the polar dielectric SiC, Q increases up to 226%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$226\\%$$\\end{document} for μ≈0.45\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mu \\approx 0.45$$\\end{document} eV. Our results show that, in addition to the geometric control achieved with uncoated NP arrays, the tunable optical properties of the graphene shell allow dynamic control of the heat flux, expanding the possibilities for NFRHT engineering offered by GCNP metasurfaces.

Influence of graphene nanoplatelets on the thermal conductivity of heat transfer oils based on the developed hotwire method

The thermal conductivity measurements of graphene nanoplatelets (GNP) loaded mineral oil suspensions are obtained using an unconventional custom-made Transient Hot-Wire setup using tungsten. The presence of a few layers of graphene in the prepared GNP using a single-step ultrasonication of graphite microparticles without the use of a surfactant is verified by AFM, TEM, Raman Spectroscopy, XRD, and XPS techniques. We measured the thermal conductivity and the specific heat capacity ( Cp ) of GNP-loaded mineral oil suspensions. The experimental result shows a maximum of 45.5% increment in the thermal conductivity of the mineral oil with 1 mg ml−1 (11.481 ×10−4 weight fraction) loading of GNP at 30 °C. Despite thermal conductivity enhancements, the results indicate that the Cp is not compromised, since a low concentration of nanoplatelets was used. The experimental results agree with the Maxwell-Garnett effective medium approach (MGEMA) model for the thermal conductivity of nanofluids which we found to be suitable for lower loading of nanoparticles. We propose GNP incorporated mineral oil suspensions are effective when it comes to heat transfer fluids even with the lower volume and mass fractions.

Boosting piezocatalytic efficiency: Thin carbon layer-modified ZnO for superior rhodamine B degradation

This study aims to enhance the piezocatalytic activity of ZnO by modifying it with a thin carbon layer (TCL). The composite catalysts were synthesized using a simple hydrothermal method. The tightly adhered TCL served as an effective electron transfer medium, enabling the rapid migration of piezoinduced charge carriers from the ZnO to the catalyst surface, thereby facilitating the catalytic degradation of Rhodamine B (RhB). The optimized TCL/ZnO sample exhibits an RhB degradation rate 13.4 times higher than that of pure ZnO. This work demonstrates that TCL/ZnO has significant potential in piezocatalytic water purification and offers new insights into the design of efficient piezocatalytic materials.

A new airfield lighting system network architecture

Airport navigation lights are essential for safe night and adverse weatherflying. Airfield ground lighting (AGL) systems providevisual guidanceduring airport operations. These systems use multiple lamps connected inseries with constant current regulators (CCRs) to provide power. Promptdetection and location of failed lamps are critical to airport efficiency andcost savings. Local area network (LAN) communication facilitates lampmonitoring and control, improving system performance and reducingmaintenance costs. Effective transmission media are critical for systemreliability and efficiency. This article presents a new network architecturefor AGL systems that connects lamps and the control system using a newintelligent module; this architecture combines star and bus topologies in ahybrid intranet network. The obtained results show excellent networkingperformances by means oflatency and throughput. This architectureimproves operational efficiency and reduces maintenance for AGL systems.

In What Way Is Gen Zs Purchase Behavior Affected by Social Media

With the growth of the online marketplace, social media has received increasing attention as an advertising resource in recent years. An introduction to the social psychology of effective social media advertising has been studied to some extent at this stage. This paper delves into the dynamic expansion of social media and its far-reaching impact on marketing opportunities, particularly on Generation Z - a population known for its avid use of social platforms. Using a variety of search engines and specific keyword combinations, this study provides a comprehensive review of empirical studies that elucidate the relationship between purchasing behavior and Gen Z's use of social media. The study systematically integrates and evaluates various studies that have explored the impact of social media on the buying habits of Generation Z. Key aspects such as the phenomenon of followership, the quest for individuality, and the sway of social media influencers are summarized and evaluated. The paper emphasizes the critical role of social media marketing and its far-reaching impact on Generation Z's purchasing decisions.

Evaluation of Determining the Best Product Promotion Media Decisions for MSMEs with ROC Ranking Technique and SAW Ranking Method

Micro, Small, and Medium Enterprises (MSMEs) face challenges in determining effective promotional media to increase sales of their products. This research aims to evaluate and determine the best promotional media for MSMEs using the ROC (Rank Order Centroid) ranking technique and the SAW (Simple Additive Weighting) method. The criteria used include Advertising Costs, Target Market, Promotion Time, and Brand Image. Based on the calculation of criteria weights with the ROC technique and evaluation of alternatives with the SAW method, Social Media was found to be the best promotional media, followed by Search Engines and Product Collaboration. Social Media has advantages in low cost, wide target market reach, and promotional flexibility and effectiveness. Search Engines and Product Collaboration also showed good results in reaching the target market and promotional flexibility. In contrast, Print Media ranked the lowest due to limited reach and high costs. This research provides guidance for MSMEs in choosing the right promotional media and optimizing resources for maximum promotional results.

Social Inequality in the Movie Fantastic Mr. Fox

This research examined social inequality and the resulting conflicts in the movie "Fantastic Mr. Fox." The objectives were to identify and analyze the portrayal of social inequality within the film using Max Weber’s theory of social stratification. Using descriptive qualitative method, the study involved detailed analysis of the movie script to uncover these themes. The findings revealed that the farmers, representing the upper class, oppress the animal community, which symbolizes the lower class. This dynamic led to various conflicts, highlighting the struggles and resistance of the underprivileged against the powerful. Film analysis demonstrated how animated films can reflect real-world social hierarchies. In conclusion, the research provided a deeper understanding of the use of popular media to comment on societal issues and emphasizes the importance of empathy and collective action to address inequality. This study contributes to the field by showcasing the potential of animated films as tools for social commentary and education. This study highlights the capacity of animated films to serve as effective mediums for social critique, urging viewers to recognize and challenge societal inequalities. The findings underscore the necessity for empathy and collective action in addressing systemic oppression

Use of YouTube videos to Improve Students' English Pronunciation Skills

English pronunciation is a language skill that must be mastered well by students studying English, especially in the teaching department. Pronunciation that is less than perfect will result in misunderstandings and the meaning of the vocabulary can also be different. During the learning process in the classroom, the way of how to pronounce vocabulary is only given by the lecturer, which sometimes makes the class atmosphere less varied and students become less active. Therefore, this research discusses the effectiveness of videos on YouTube which are used as learning media during the English learning process in the classroom. This research uses a qualitative descriptive method with data in the form of the average results of students’ scores in English pronunciation which are tested orally. The research results show that the use of YouTube videos is very effective in improving students' pronunciation skills because the videos displayed come from native speakers who use British and American accents. In other words, videos on YouTube can become one of effective English pronunciation learning media. The research results also showed an increase of student scores in English pronunciation and students were more enthusiastic during the learning process in the classroom.

Storage Media for Dental Avulsion: A Literature Review

Tooth avulsion is a critical dental emergency where immediate and appropriate management is essential for the successful reimplantation of the tooth. The choice of storage medium during the extra-alveolar period significantly impacts the viability of periodontal ligament (PDL) cells, crucial for the long-term retention of the replanted tooth. This review examines various storage media proposed for avulsed teeth, assessing their pH, osmolality, and overall efficacy in maintaining PDL cell viability. A comprehensive literature search was conducted across databases including PubMed, Scopus, and Google Scholar, identifying media such as Hank’s Balanced Salt Solution (HBSS), milk, saline, propolis, coconut water, and more. Ideal storage media should exhibit antimicrobial properties, maintain physiological osmolality and pH, support PDL cell viability, and be readily available. HBSS is highlighted as the gold standard, with its ability to preserve PDL cells for up to 48 hours. Other effective media like milk, soy milk, and oral rehydration solutions are discussed for their accessibility and performance. Emerging media such as propolis and epigallocatechin-3-gallate show promise but require further research. This review emphasizes the importance of public awareness and accessibility to effective storage media to improve the prognosis of avulsed teeth. Keywords: Storage Media, Dental Avulsion, PDL viability.

Equilibrium vapor pressure of aqueous sodium acetate and potassium acetate solutions used as working fluids in frost-free air–source heat pumps at 263–328 K

Aqueous solutions of sodium acetate (CH3COONa) and potassium acetate (CH3COOK) are considered effective alternative heat exchange media for frost-free air–source heat pumps (FFASHPs) owing to the low corrosiveness, low viscosity, and low cost. Equilibrium vapor pressure is the most crucial property that characterizes freezing point and latent heat transfer. However, studies on this property, especially in subzero temperature ranges are scarce. This study was conducted to experimentally investigate the equilibrium vapor pressure of CH3COONa and CH3COOK solutions. The developed apparatus and procedures were based on the static method, and validated by evaluating the vapor pressure of distilled water, n-heptane, and calcium chloride (CaCl2) aqueous solution. Their average absolute deviations were within 1.94%. As the temperature increased from 263 to 328 K and solute concentration increased from 9.27 to 33.81 wt%, 124 data points of the vapor pressure of the CH3COONa and CH3COOK solutions were obtained, ranging from 0.2759 to 13.2608 kPa. Modified Antoine equation and ion interaction (Pitzer) model were established for correlation of the experimental data. The average absolute deviations of the CH3COONa and CH3COOK solutions produced by Antoine equation were 2.08 and 2.48%, respectively. Those produced by Pitzer model further decreased to 1.36 and 1.45% due to the import of osmotic coefficient and the accuracy improvement. Furthermore, according to the experimental and calculation results, the vapor pressure of the CH3COONa solution was lower than that of the CH3COOK solution. Therefore, under the same antifreezing conditions, the CH3COONa solution facilitates latent heat absorption from ambient air, while the CH3COOK solution is conducive to achieve regeneration. The results of this study provide foundational data for the vapor pressure of the two solutions and can promote their application in FFASHPs.

Regulation of macroporous cellulose microspheres via phase separation force induced by carbon nanotubes doping for enhanced protein adsorption

The burgeoning requirement for purified biomacromolecules in biopharmaceutical industry has amplified the exigency for advanced chromatographic separation techniques. Herein, macroporous cellulose microspheres (CCMs) with micron-sized pores are produced by a facile regulation via carbon nanotubes (CNTs). In this strategy, the incorporation of CNTs breaks the homogeneous regeneration of the cellulose, thus providing anisotropic phase force to produce macropores. The CCMs have manifested a faster mass transfer rate and more available adsorption sites owing to well-defined macropores (2.69 ± 0.57 μm) and high specific surface area (147.47 m2 g−1). Further, CCMs are functionalized by quaternary ammonium salts (GTAc-CCMs) and utilized as anion adsorbents to adsorb pancreatic kininogenase (PK). The prepared GTAc-CCMs show rapid adsorption kinetics for PK at pH 6.0, reaching 90 % equilibrium within 60 min. Also, GTAc-CCMs for PK exhibit high adsorptive capacity (632.50 mg g−1), excellent recyclability (> 80 % removal amount after 10 cycles) and selectivity especially at pH 6.0. Notably, the GTAc-CCMs have been successfully applied in a fixed-bed chromatography process, indicating their potential as an effective chromatographic medium for rapid separation of biomacromolecules.

Orientation and shape distributions effective medium theory (OSDEMT): Applications in plasmonic nanocomposites

Plasmonic anisotropic nanocomposites containing in particular nanorods and nanowires are gaining increasing interest due to their remarkable physical and optical properties. In this paper, we introduce a novel effective medium theory which we call “Orientation and Shape Distributions Effective Medium Theory” (OSDEMT), to describe the optical properties of a 3D arrangement of metallic nanorods in a dielectric matrix. The effective dielectric properties of plasmonic nanocomposites containing nanorods with different shape and orientation configurations were simulated and analyzed using OSDEMT. We demonstrate that the amplitudes of the longitudinal and transverse surface plasmonic resonances depend on the orientation distribution of the nanostructures, when their positions remain unchanged. Moreover, we show that the anisotropic properties of the nanocomposites are very sensitive to the aspect ratios of the nanorods so that even spherical-centered shape distributions exhibit anisotropic properties when oriented. Finally, we confront the OSDEMT to UV–visible extinction measurements conducted on gold nanorods in a toluene suspension.

Developing Android App-Based Interactive Learning Media for Mechanical Engineering Basics: Enhancing Vocational School Student Learning Outcomes

This study is to provide valid, practical, and effective Android application-based interactive learning media for the Basics of Mechanical Engineering subject in class X Mechanical Engineering at SMK Dhuafa Padang. This medium is intended to boost students' comprehension, motivation, and independence, allowing them to achieve better learning outcomes. The research approach employed is Research and Development (R&D), using a 4D development model (define, design, develop and disseminate). The primary data utilized in this study came from validators, teachers, and students. Data was analyzed descriptively to characterize the validity, practicality and effectiveness of the learning media developed. The validity test findings show that this learning medium, which had a media aspect score of 0,892 and a material aspect score of 0,950, was deemed valid by expert review. This media was also declared practical with a practicality score of 96,94% from teacher responses and 92,25% from student responses. In the effectiveness test, the Gain Score was 0,68, placing it in the medium category. Meanwhile, the t-test shows a Sig value (2-tailed) of 0.002 (2-tailed < 0,05) and a tcount value of 3,372 (tcount ˃ ttable), indicating a significant difference in learning outcomes between students who use this learning media (experimental class) and those who do not use the media (control class). Thus, this Android application-based interactive learning media is declared valid, practical and effective for use in the DDTM learning process.

The Use of Board Games for EFL Learning

Nowadays, digital-based media-integrated is needed in the learning context. This study aims to find out the teacher's perspective on the use of board games as a for EFL learning. This research used a descriptive qualitative approach with an in-depth interview instrument. The participant was one English teacher in a private Junior High School in Malang Regency. The data was displayed descriptively. With the advent of digital technology, the result showed that board game still have various benefits. By using board games, teacher motivate students and make the learning process understandable. Board games are also an effective teaching media for improving motivation in learning English. Board games increase student participation, motivation, and enjoyment, making learning more efficient and fun. It is showed that board games improve students' scores in English class. The board game showed that students were more active during English learning. It is concluded that board games improve students' ability to learn English. Thus, it is recommended that board games be used as a learning media for EFL learning.

Ultrabroadband invisibility cloaking design of a concentric multilayered cylindrical metamaterial

An ultrabroadband invisibility cloak is designed using a genetic algorithm (GA) for a cylindrical target with an infinite length. The cloaking band is 0.4 to 0.7µm, covering almost the entire visible light range. The invisibility cloaking medium consists of concentric multilayered cylindrical metamaterials (CM). When the cloaking target is covered with a well-designed 26+ layer CM, the average scattering cross-section is 6% or less of the uncloaked target’s cross-section. The cloaking performance of the structure designed by the GA was superior to that designed by analytical calculations based on a combination of the transformation optics and the effective medium approximation. The cloaking is confirmed through the time variation of the magnetic fields calculated using the finite-difference time-domain method. In addition, the mechanism of the cloaking is discussed.

Effective Media Validation, Benefits and Costs for Achieving High Yield in Ribbed Gourd in Soilless Culture under Matric Suction Irrigation

Aims: To standardize an appropriate method of finding suitable particulate organic substrates for composing soilless media, a soilless experiment was conducted in an open wasteland area in pandal system under matric suction irrigation Study Design: Completely Randomized Design Place and Duration of Study: Department of Soil Science and Agricultural Chemistry, Anbil Dharmalingam Agricultural College and Research Institute, Trichy, Tamil Nadu during Rabi 2020-2021 Methodology: Three growing media were tested with ten replications. For composing the growing media equal proportion (on a weight basis) of substrates viz., coir pith, vermicompost, fly ash, green manure (Dhaincha), and sand were mixed in different combinations. Ribbed gourd CoH-1 was raised in growing media in containers that were interconnected by tubs and tubes to maintain moisture always by matric suction irrigation technique. Results: Growing media having Coir pith: Vermicompost: Green Manure: Sand registered the highest fruit yield (10.033 kg pot-1), water use efficiency (411.2 kg fresh fruit mm-1) and benefit-cost ratio (1.95) than that of the growing media combination with fly ash. This green manure combination significantly recorded 18% more yield and water use efficiency than that of the coir pith and vermicompost combination. Apparent nutrient recovery was highest in the growing media with coir pith: vermicompost: green manure: sand for N (22.42%), P (23.47%), and K (192.9%). Conclusion: Exploitation of the potentiality of particulate organic materials demonstrated in this soilless system technique may be useful for farmers to generate additional farm income with proper use of particulate organic substrates obtainable/ available in their farm.

Preparation of catalyst for CO2 hydrogenation reaction based on the idea of element sharing and preliminary exploration of catalytic mechanism.

Under the background of the continuous rise of CO2 annual emissions, the development of CO2 capture and utilization technology is urgent. This study focuses on improving the catalytic capacity of the catalyst for CO2 hydrogenation, improving the efficiency of CO2 conversion to methanol, and converting H2 into chemical substances to avoid the danger of H2 storage. Based on the concept of element sharing, the ASMZ (Aluminum Shares Metal Zeolite catalysts) series catalyst was prepared by combining the CuO-ZnO-Al2O3 catalyst with the ZSM-5 zeolite using the amphoteric metal properties of the Al element. The basic structural properties of ASMZ catalysts were compared by XRD, FTIR, and BET characterization. Catalytic properties of samples were measured on a micro fixed-bed reactor. The catalytic mechanism of the catalyst was further analyzed by SEM, TEM, XPS, H2-TPR, and NH3-TPD. The results show that the ASMZ3 catalyst had the highest CO2 conversion rate (26.4%), the highest methanol selectivity (76.0%), and the lowest CO selectivity (15.3%) in this study. This is mainly due to the fact that the preparation method in this study promotes the exposure of effective weakly acidic sites and medium strength acidic sites (facilitating the hydrogenation of CO2 to methanol). At the same time, the close binding of Cu-ZnO-Al2O3 (CZA) and ZSM-5 zeolite also ensures the timely transfer of catalytic products and ensures the timely play of various catalytic active centers. The preparation method of the catalyst in this study also provides ideas for the preparation of other catalysts.

Pulse-doubling perovskite nanowire lasers enabled by phonon-assisted multistep energy funneling

Laser pulse multiplication from an optical gain medium has shown great potential in miniaturizing integrated optoelectronic devices. Perovskite multiple quantum wells (MQWs) structures have recently been recognized as an effective gain media capable of doubling laser pulses that do not rely on external optical equipment. Although the light amplifications enabled with pulse doubling are reported based on the perovskite MQWs thin films, the micro-nanolasers possessed a specific cavity for laser pulse multiplication and their corresponding intrinsic laser dynamics are still inadequate. Herein, a single-mode double-pulsed nanolaser from self-assembled perovskite MQWs nanowires is realized, exhibiting a pulse duration of 28 ps and pulse interval of 22 ps based on single femtosecond laser pulse excitation. It is established that the continuous energy building up within a certain timescale is essential for the multiple population inversion in the gain medium, which arises from the slowing carrier localization process owning to the stronger exciton–phonon coupling in the smaller-n QWs. Therefore, the double-pulsed lasing is achieved from one fast energy funnel process from the adjacent small-n QWs to gain active region and another slow process from the spatially separated ones. This report may shed new light on the intrinsic energy relaxation mechanism and boost the further development of perovskite multiple-pulse lasers.

Interactive learning media development in Purwokerto city: cognitive aspects of school basketball

Teachers' learning methods for sports and health are still conventional, such as lectures, discussions, and assignments, but teachers have not yet applied learning using interactive learning technologies, especially in basketball games. The aim of this research is to produce effective interactive learning media to enhance the knowledge of students. The research method used is Research and Development (RnD) using the Borg and Gall model. The subjects in this study included validators, physical education teachers, and grade XI students from all public high schools in Purwokerto City (Public High Schools 1, 2, 3, 4, and 5). Data analysis techniques use quantitative descriptive analysis. The product test suffered audio constraints overcome through improvements and showed a score of 86.20%. After improvements, the usage test of 62 students and five teachers showed very high scores, reaching 95.72% of students and 96.40% of teachers. The results of the effectiveness test showed that interactive learning media has a significant influence on students' cognitive abilities. Keywords: Development, Interactive Learning Media, Cognitive Aspects, Basketball

Efektifitas Penggunaan Media Audiovisual pada Pembelajaran Anatomi Tubuh Manusia di Tingkat Sekolah

This research examines the effectiveness of using audiovisual media in teaching human anatomy at school level. The literature review was carried out by analyzing various trusted sources, such as scientific journals, books and online articles. The research results showed that the application of audiovisual media was proven to increase students' understanding and learning achievement in human anatomy subjects. The most effective audiovisual media are animated videos, 3D anatomical images, and interactive simulations. Appropriate use of audiovisual media helps students understand the structure and function of the human body better. Conclusion: Audiovisual media is an effective learning strategy to improve students' understanding and learning achievement in human anatomy subjects. Teachers need to use appropriate and varied audiovisual media in learning human anatomy to achieve optimal learning outcomes