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Developing thermoelectric films without substrates—free-standing films—eliminates substrate-induced effects on performance and meets the flexibility requirements of emerging wearable thermoelectric applications. This study investigates Gallium-doped Zinc Oxide (GZO), composed of abundant and non-toxic elements, to fabricate a substrate-free GZO film via 3D printing and compares its structural, chemical, and thermoelectric properties with those of a substrate-constrained GZO film produced through chemical deposition. Both films exhibited uniform crystal structures and phase purity; however, the substrate-constrained film displayed additional diffraction peaks, suggesting potential substrate interactions. The 3D-printed free-standing film effectively eliminated the tensile stresses observed in the substrate-constrained film. FE-STEM analysis revealed nanostructures with homogeneous elemental distribution in both films, though the substrate-constrained film showed discontinuities, such as pores, likely caused by post-deposition annealing treatment. XPS analysis highlighted differences in chemical states and elemental compositions between the films, influenced by fabrication methods, substrate-induced stresses, and surface energy mismatches. The free-standing GZO film developed through 3D printing exhibited a more balanced incorporation of Zn and O, as it was not subject to substrate or post-deposition annealing constraints. Consequently, it demonstrated a 14 % increase in electrical conductivity and a 91 % improvement in the Seebeck coefficient compared to the substrate-constrained film, resulting in a higher room-temperature power factor of 261 nW/m·K2. These findings underscore the potential of 3D-printed free-standing GZO films to advance thermoelectric applications, offering a promising alternative to overcome the challenges of substrate-constrained films and further drive innovation in the field.

This systematic review seeks to improve the existing framework for developing students’ Computing Identity (CI) by integrating contemporary elements and identifying new dimensions. A meticulous selection of 31 articles followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) protocol, ensuring a comprehensive and systematic approach. The findings highlight factors that influence students’ CI and also the constructs defining the frameworks for developing students’ CI. The identified existing constructs are competence/performance, interest, sense of belonging, and recognition in computing, with competence/performance being the most explored and recognition the least. The review proposes a new framework for developing students’ CI that includes the “social context” as it interweaves with existing constructs to shape the multifaceted process of CI formation. The findings underscore a research gap concerning the inclusion of diverse perspectives, which is essential for a richer understanding of CI. Additionally, the study emphasizes the potential to incorporate new elements to enhance the existing frameworks for developing students’ CI, along with its validation in diverse contexts.

Abstract This article systematically reviews the pedagogies employed in mixed-ability high school biology classrooms to spotlight the most effective educational model, in terms of learning gains. A meta-analysis was performed on 32 eligible studies sorted via the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. The effect sizes (impacts) were calculated in terms of students’ affective, behavioral, and cognitive gains. The results confirmed that the overall effectiveness of non-traditional models was highly significant when compared to traditional lecture models (p

IntroductionEducators play a pivotal role in shaping students’ academic achievements, particularly in STEM (science, technology, engineering, and mathematics) fields. The instructional techniques employed by teachers significantly impact students’ decisions to pursue or persist in STEM disciplines. This research aims to explore the challenges faced by high school STEM teachers in Qatar in delivering effective STEM instruction.MethodsData was collected through a survey administered to 290 high school STEM teachers across thirty-nine schools in Qatar. The survey targeted teachers in the 11th and 12th grades. Structural Equation Modeling (SEM) was utilized to analyze the data and examine teachers’ perceived barriers to effective STEM instruction.ResultsThe findings revealed various barriers hindering STEM instruction. These barriers were categorized into school-related, student-related, technology-related, and teaching-related factors. All the hypothesized teaching barriers [i.e., (student-related: β = –0.243, p < 0.001); (school-related: β = –0.122, p < 0.001), (technologyrelated: β = –0.123, p = 0.040); and (instruction-related: β = –0.112, p < 0.018)] were negatively related to teachers’ STEM teaching. Among the various obstacles, it appears that the most formidable challenges for high school STEM teachers are related to students (β = –0.243, p < 0.001).DiscussionUnderstanding these barriers is crucial for informing educational policies and developing strategies to enhance STEM learning in Qatar’s high schools. Addressing these barriers is essential to provide adequate resources, professional development opportunities, and support systems. By addressing these challenges, Qatar can foster a conducive environment for effective STEM instruction, thereby nurturing a future generation of STEM professionals.

Despite massive investments in the education sector to empower youth in Qatar, a vital concern remains to retain students in science, technology, engineering, and mathematics (STEM) disciplines at the undergraduate level. Even though the country is committed to fostering a knowledge-based society, the low interest of undergraduates in STEM disciplines remains a vital challenge. To investigate this, the current study uses a survey methodology to investigate the perspectives of 172 undergraduate students to understand quantitatively the factors that influence their individual interests in STEM disciplines. Non-parametric significance tests and binary logistic regressions were employed to quantitatively measure the direct factors and predictors that affect students’ individual interests. Findings indicated that aspects like students’ reason/motivation to join STEM, their interaction with faculty, the habit of skipping classes, the difficulty faced in the curriculum, and their parents’ highest educational qualification have an association with individual interests. Also, it was found that demographics such as age group, ethnicity, undergraduate discipline, undergraduate year, parent’s employment status, and mother’s highest educational qualification do not contribute to significant differences in students’ individual interests. These conclusions provide important implications for educationists and policymakers to devise constructive reforms to enhance undergraduate students’ individual interests, thereby improving their persistence in STEM.

Research Experience programs (REPs) inspire students to pursue advanced degrees and shape their research career paths. Government and commercial organizations sponsor REPs to promote the capacity building of the country. In Qatar, the national youth is reported to show concerning participation in Science, Technology, Engineering, and Mathematics (STEM) disciplines at the K-12 level. However, none of the studies investigate these participation trends at the undergraduate level, especially in scientific research, which is deemed necessary for building a knowledge-based economy in Qatar. Therefore, to bridge this gap, the current study uses a quantitative approach to analyze the REP in Qatar through the participation data of 2455 undergraduate students. For this, statistical measures, including descriptive analysis, independent samples t-test, and Pearson's correlation analysis were used. Results indicated concerning trends in national student participation rate, implying underlying issues restricting their representation in undergraduate research activities. Also, statistically significant differences were found in student participation rates among students' gender and ethnic distributions. While female students demonstrated higher participation rates than males, national students showed lower participation than the non-nationals. Moreover, this low participation of national students suffered more drastically in STEM disciplines. Therefore, these findings determine the outlook for stakeholders and academic institutions in making meaningful educational decisions and envision synchronizing REPs at the university level, gauging measures to bolster the adjacent funding agencies and government organizations. Furthermore, being the first research addressing REPs in the Middle East region, this study has the potential to support educators in neighboring and other developing nations where STEM education is especially significant for human capacity building.

The state-of-the-art thermoelectric technology owns a unique capability of direct, noise-free, and efficient conversion of waste heat into valuable electricity. The conventional thermoelectric generators are complex and expensive in fabrication, which restricts their use in wearable and miniaturized electronics to fulfill the current and rapid growth in demands for sufficient self-powered energy harvesters. Herein, this comprehensive review paper highlights the promising and next-generation thermoelectric generators based on flexible, transparent, abundant, non-toxic, and lightweight p-type Copper Iodide (CuI) thin films. It introduces the principles of energy conversion within thin-film thermoelectric generators and the structure of p–n junction including the criteria in the selection of substrates, p-type and n-type materials, connecting electrodes, and modules designed to sustain its mechanical flexibility and optical transparency. This review underlines the morphology and properties of CuI thin-film thermoelectric generators to figure out the latest trends in advanced synthesis and characterization techniques. It draws attention to its promising applications in wearable biosensing, energy harvesting, and smart miniaturized electronics. It discusses also the challenges and prospects in boosting the thermoelectric performance of CuI thin-film generators. This targeting to exceed the unity in its Figure-of-Merit (ZT) values for excellent output power generation, large-scale production for commercialization, and long-term stability for reliable thermoelectric applications.

Corrosion-related damage incurs significant capital costs in many industries. In this study, an anti-corrosive pigment was synthesized by modifying calcium carbonate with sodium alginate (SA), and smart self-healing coatings were synthesized by reinforcing the anti-corrosive pigments into a polyolefin matrix. Structural changes during the synthesis of the anti-corrosive pigment were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Moreover, thermal gravimetric analysis confirmed the loading of the corrosion inhibitor, and electrochemical impedance spectroscopic analysis revealed a stable impedance value, confirming the improved corrosion resistance of the modified polyolefin coatings. The incorporation of the anticorrosive pigment into a polyolefin matrix resulted in improved pore resistance properties and capacitive behavior, indicating a good barrier property of the modified coatings. The formation of a protective film on the steel substrate reflected the adsorption of the corrosion inhibitor (SA) on the steel substrate, which further contributed to enhancing the corrosion resistance of the modified coatings. Moreover, the formation of the protective film was also analyzed by profilometry and elemental mapping analysis.

Abstract Segmentation of abdominal Computed Tomography (CT) scan is essential for analyzing, diagnosing, and treating visceral organ diseases (e.g., hepatocellular carcinoma). This paper proposes a novel neural network (Res-PAC-UNet) that employs a fixed-width residual UNet backbone and Pyramid Atrous Convolutions, providing a low disk utilization method for precise liver CT segmentation. The proposed network is trained on medical segmentation decathlon dataset using a modified surface loss function. Additionally, we evaluate its quantitative and qualitative performance; the Res16-PAC-UNet achieves a Dice coefficient of 0.950 ± 0.019 with less than half a million parameters. Alternatively, the Res32-PAC-UNet obtains a Dice coefficient of 0.958 ± 0.015 with an acceptable parameter count of approximately 1.2 million.

This study sought to explore high school students' interest in science, technology, engineering, and mathematics (STEM) related disciplines and careers in the context of Qatar. Quantitative data was collected using a survey of 1492 high school students in grades 11–12. The normality tests (Shapiro-Wilk test and Kolmogorov Smirnov test) revealed the non-normal distribution of data, leading to employing non-parametric analyses, including Mann Whitney U test, Kruskal Wallis H, and logistic regression. Results indicated that whereas students' interest in mathematics and science subjects was aligned with their likelihood to pursue STEM careers, however, their interest in engineering and technology doesn't line up with their STEM career aspirations. The findings also revealed the variability of students' STEM interests across gender and nationality. In general, female students exhibited higher STEM interests than their male counterparts, while specially expatriates were more inclined toward STEM than Qatari nationals. Overall, these findings postulate the need to improve the exposure of males in general and Qatari nationals specifically to STEM fields of study, particularly the subjects of engineering and technology, to meet the goals of Qatar's National Vision 2030.

Silicon/perovskite tandem devices are believed to be a favorite contender for improving cell performance over the theoretical maximum value of single-junction photovoltaic (PV) cells. The present study evaluates the design and optimization of four-terminal (4-T) mechanically stacked and optically coupled configurations using SCAPS (solar cell capacitance simulator). Low-cost, stable, and easily processed semitransparent carbon electrode-based perovskite solar cells (c-PSCs) without hole transport material (HTM) and highly efficient crystalline silicon (c-Si) PV cells were utilized as top and bottom cells, respectively. The wide bandgap multi-cation perovskite Csx(FA0.4MA0.6)1−xPbI2.8Br0.2 and a low bandgap c-Si were employed as light-harvesting layers in the top and bottom cells, respectively. The impact of perovskite thickness and doping concentrations were examined and optimized for both tandem configurations. Under optimized conditions, thicknesses of 1000 nm and 1100 nm are the best values of the perovskite absorber layer for 4-T mechanically stacked and optically coupled arrangements, respectively. Likewise, 1 × 1017 cm−3 doping concentration of top cells revealed the highest performance in both structures. With these optimized parameters under tandem configurations, efficiency values of 28.38% and 29.34% were obtained in 4-T mechanically and optically coupled tandems, respectively. Results suggest that by optimizing perovskite thickness and doping concentration, the proposed designs using HTM-free c-PSCs could enhance device performance.

Abstract Perovskite solar cells (PSCs) expressed great potentials for offering a feasible alternative to conventional photovoltaic technologies. 2D/3D hybrid PSCs, where a 2D capping layer is used over the 3D film to avoid the instability issues associated with perovskite film, have been reported with improved stabilities and high power conversion efficiencies (PCE). However, the profound analysis of the PSCs with prolonged operational lifetime still needs to be described further. Heading towards efficient and long-life PSCs, in-depth insight into the complicated degradation processes and charge dynamics occurring at PSCs' interfaces is vital. In particular, the Au/HTM/perovskite interface got a substantial consideration due to the quest for better charge transfer; and this interface is debatably the trickiest to explain and analyze. In this study, multiple characterization techniques were put together to understand thoroughly the processes that occur at the Au/HTM/perovskite interface. Inquest analysis using current–voltage (I–V), electric field induced second harmonic generation (EFISHG), and impedance spectroscopy (IS) was performed. These techniques showed that the degradation at the Au/HTM/perovskite interface significantly contribute to the increase of charge accumulation and change in impedance value of the PSCs, hence resulting in efficiency fading. The 3D and 2D/3D hybrid cells, with PCEs of 18.87% and 20.21%, respectively, were used in this study, and the analysis was performed over the aging time of 5000 h. Our findings propose that the Au/HTM/perovskite interface engineering is exclusively essential for attaining a reliable performance of the PSCs and provides a new perspective towards the stability enhancement for the perovskite-based future emerging photovoltaic technology.

NH3 is a highly harmful gas; when inhaled at levels that are too high for comfort, it is very dangerous to human health. One of the challenging tasks in research is developing ammonia sensors that operate at room temperature. In this study, we proposed a new design of an NH3 gas sensor that was comprised of two-dimensional (TMDs, mainly WS2 and MoS2) and PANI. The 2D-TMDs metal was successfully incorporated into the PANI lattice based on the results of XRD and SEM. The elemental EDX analysis results indicated that C, N, O, W, S and Mo were found in the composite samples. The bandgap of the materials decreased due to the addition of MoS2 and WS2. We also analyzed its structural, optical and morphological properties. When compared to MoS2 and PANI, the proposed NH3 sensor with the WS2 composite was found to have high sensitivity. The composite films also exhibited response and recovery times of 10/16 and 14/16 s. Therefore, the composite PANI/2D-TMDs is a suitable material for NH3 gas detection applications.

This method solves the problem of fabrication of flexible elastic conductive thin film samples for thermoelectric applications. For this purpose, rubbing in technology at room temperature condition has been used which is simple, economical and reliable. As a result, elastic thermo-electric cells have been fabricated that can be used for low power applications and for measurement of the gradient of temperature in industry, medicine and in instrumentation as well. The elastic nature of the thermo-electric cells allows us to place the “hot” and “cold” points of the thermo-electric cells in different planes that make these thermo-electric cells useful for different kind of applications without limitation to place them in a line or in a plane. Method name: Rubbing technique, Keywords: Rubbing-in-technology, Flexible conductive thin film, Thermo-electric-cell

We report the effect of applied pulse width on charge accumulation in triple cation perovskite solar cells (PSCs) during the Electric Field Induced Second Harmonic Generation (EFISHG) measurements. The PSCs were prepared in the n-i-p structure using the layer-by-layer deposition technique. The triple cation perovskite precursor containing FAPbI3, MAPbBr3, and CsPbI3 was used to make the perovskite layer on the FTO/c-TiO2/mTiO2 substrates. Spiro OMeTAD was used as a hole transport material over the perovskite active layer, followed by the deposition of Au electrodes. The average power conversion efficiency (PCE) of the fabricated PSCs was 19.17 ± 0.02%. The electric field in the PSCs was selectively probed by the fundamental laser beam wavelength of 960 nm during the EFISHG measurements. Two different pulse widths (100 µs and 50 ms) of the applied potential were used in this study, with consideration of electrode charging and interface charging of PSCs. It has been observed that the pulse width of the applied electric field has a significant effect on the charge accumulation in the PSCs. Using the transient EFISHG measurements, it has also been found that the charging & discharging processes reversibly happen. However, the charging & discharging processes are influenced by remained charges at the interface in PSCs in the investigated triple cations PSCs. The EFISHG results can be well explained by using the Maxwell–Wagner model.

Pitting corrosion is a significant concern for the broader application of stainless steel in modern industries in which metal and metal alloy are detached preferentially from susceptible parts on the surface, resulting in the creation of holes in passivated alloys that are exposed to an aqueous, neutral electrolyte containing corrosive species. Exposure of SS to brines leads to the localized loss of surface passivity and the onset of isolated pitting, which render the equipment or piping unfit for service. In the present study, the passive layer behavior and the pitting corrosion of the modified martensitic stainless steel (MMSS) were evaluated in a saturated CO2 environment (pH~5) with different NaCl concentrations and temperatures, using various electrochemical techniques. It was found that by increasing the temperature up to 60 °C, the corrosion resistance of the MMSS increased; however, the corrosion rate dramatically increased at 80 °C, indicating the destruction of the oxide layer. According to the point defect model (PDM) results, the calculated values of polarizability (α), metal cation diffusivity (D), and the rate of annihilation of cation vacancies (jm), reveal a strong dependence on the solution temperature.

Despite the remarkable progress in perovskite solar cells (PSCs), their instability and rapid degradation over time still restrict their commercialization. A 2D capping layer has been proved to overcome the stability issues; however, an in-depth understanding of the complex degradation processes over a prolonged time at PSC interfaces is crucial for improving their stability. In the current work, we investigated the stability of a triple cation 3D ([(FA0.83MA0.17)Cs0.05]Pb(I0.83Br0.17)3) and 2D/3D PSC fabricated by a layer-by-layer deposition technique (PEAI-based 2D layer over triple cation 3D perovskite) using a state-of-art characterization technique: electrochemical impedance spectroscopy (EIS). A long-term stability test over 24 months was performed on the 3D and 2D/3D PSCs with an initial PCE of 18.87% and 20.21%, respectively, to suggest a more practical scenario. The current-voltage (J-V) and EIS results showed degradation in both the solar cell types; however, a slower degradation rate was observed in 2D/3D PSCs. Finally, the quantitative analysis of the key EIS parameters affected by the degradation in 3D and 2D/3D PSCs were discussed.

Purpose: Research internships are integral components of undergraduate programs that nurture students' skill sets. However, the current trend of these internships adopting a direct apprenticeship model, often termed "cookbook" laboratory sessions, falls short of cultivating 21st-century skills. Therefore, this study proposes an innovative Outcomes-directed Research Internship Model (ODRIM) designed to enhance research competencies. Design/methodology/approach: This study introduces a pioneering research internship model by integrating the course-based undergraduate research experience (CURE) framework with principles rooted in outcomes-based education (OBE). To evaluate its effectiveness and compare it with traditional research internship models (TRIMs), a two-group pretest-posttest design was utilized. Statistical analysis was performed on data collected from 66 participants to assess their research competencies. Findings: The results revealed a significant positive difference in utilizing the tailored innovative ODRIM track (pre-mean = 17.525, post-mean = 19.875; p = 0.009) compared to the TRIM track (pre-mean = 19.769, post-mean = 19.615; p = 1.000) in enhancing overall student research competency. Specifically, this innovative internship model notably enhanced students' abilities in conducting research, showcasing technical skills, collaborating within teams, and disseminating research outcomes, encompassing the composition of research articles and reports. Originality/value This tailored approach to the "Research Internship" encourages a harmonious blend of hands-on, inquiry-based learning and clear, measurable learning goals. It not only cultivates an immersive and thorough research experience to improve students' research competencies, but also guarantees a concentrated alignment with predetermined research learning objectives.

This work presents an in-depth analysis of the alternating current (AC) conductivity of polyaniline-polystyrene (PANI-PS) blends doped with camphor sulfonic acid (CSA) and prepared using an in situ dispersion polymerization technique. We prepared the blends using fixed ratios of PS to PANI while varying the concentration of the CSA dopant. The AC conductivity of the blends was investigated using broadband dielectric spectroscopy. Increasing CSA resulted in a decrease in the AC conductivity of the blends. This behaviour was explained in terms of the availability of a lone pair of electrons of the NH groups in the polyaniline, which are typically attacked by the electron-withdrawing sulfonic acid groups of CSA. The conductivity is discussed in terms of changes in the dielectric permittivity storage (ε′), loss (ε′′), and modulus (M′′) of the blends over a wide range of temperatures. This is linked to the glass transition temperature of the PANI. Dielectric spectra at low frequencies indicated the presence of pronounced Maxwell-Wagner-Sillars (MWS) interfacial polarization, especially in samples with a low concentration of CSA. Electrical conduction activation energies for the blends were also calculated using the temperature dependence of the direct current (DC) conductivity at a low frequency (σdc), which exhibit an Arrhenius behaviour with respect to temperature. Scanning electron microscopy revealed a fibrous morphology for the pure PANI, while the blends showed agglomeration with increasing CSA concentrations.

This article is focused on the effectiveness of an innovative research-based learning model that employs chemistry-based research projects in developing high school students' research competency and attitudes. The chemistry-based research projects were carried out as a part of an informal program, in real-world laboratories on 330 high school students from 2010 to 2020 integrating different branches of chemistry, including physical, organic, inorganic, electrochemistry, and biochemistry, in addition to other science and engineering areas. The chemistry subjects harmonize with many science and engineering disciplines, thus providing an immense research scope in various multidisciplinary topics. The data were collected using a mixed method by performing an indirect assessment on the program effectiveness, conducting surveys on students, research assistants, and the research faculty mentors involved in the program. The program was primarily successful in developing students' research self-efficacy and fostering their research competencies in multidisciplinary science. Further research targets to analyze the long-term effect of the multidisciplinary research experiences on their attitudes toward higher education and research-oriented careers that can contribute to a knowledge-based economy.