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Öğe A review of relevant parameters for assessing indoor air quality in educational facilities(Academic Press Inc Elsevier Science, 2024) Branco, Pedro T. B. S.; Sousa, Sofia I. V.; Dudzinska, Marzenna R.; Ruzgar, Duygu Gazioglu; Mutlu, Mustafa; Panaras, Georgios; Weersink, AnnemarieIndoor air quality (IAQ) in educational facilities is crucial due to the extended time students spend in those environments, affecting their health, academic performance, and attendance. This paper aimed to review relevant parameters (building characteristics and factors related with occupancy and activities) for assessing IAQ in educational facilities, and to identify the parameters to consider when performing an IAQ monitoring campaign in schools. It also intended to identify literature gaps and suggest future research directions. A narrative literature review was conducted, focusing on seven key parameters: building location, layout and construction materials, ventilation and air cleaning systems, finishing materials, occupant demographics, occupancy, and activities. The findings revealed that carbon dioxide (CO2) levels were predominantly influenced by classroom occupancy and ventilation rates, while particulate matter (PM) concentrations were significantly influenced by the building's location, design, and occupant activities. Furthermore, this review highlighted the presence of other pollutants, such as trace metals, polycyclic aromatic hydrocarbons (PAHs), carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), and radon, linking them to specific factors within the school environment. Different IAQ patterns, and consequently different parameters, were observed in various school areas, including classrooms, canteens, gymnasiums, computer rooms, and laboratories. While substantial literature exists on IAQ in schools, significant gaps still remain. This study highlighted the need for more studies in middle and high schools, as well as in other indoor microenvironments within educational settings beyond classrooms. Additionally, it underscored the need for comprehensive exposure assessments, long-term studies, and the impacts of new materials on IAQ including the effects of secondary reactions on surfaces. Seasonal variations and the implications of emerging technologies were also identified as requiring further investigation. Addressing those gaps through targeted research and considering the most updated standards and guidelines for IAQ, could lead to define more effective strategies for improving IAQ and safeguarding the students' health and performance.Öğe Cold spray-based rapid and scalable production of printed flexible electronics(Elsevier, 2022) Akin, Semih; Lee, Seungjun; Jo, Seunghwan; Ruzgar, Duygu Gazioglu; Subramaniam, Karthick; Tsai, Jung -Ting; Jun, Martin Byung-GukFlexible electronics (FE) is attracting great attention from both scientific and industrial communities, and plays a crucial role in smart device applications. Despite great promise, traditional printing approaches (e.g., screen printing, ink-jet printing, etc.) often need a high-temperature post-sintering process to produce FE with desired electrical conductivity and adhesion strength. The post-sintering processes, however, often lead to fast oxidation of the functional coating while limiting the use of low-thermal budget substrates. Exponential advance of FE in a large-scale and energy-efficient manner relies on rationally eliminating the post-sintering processes. To this end, with the aim of uncovering process-structure-properties relationships, we employ the emerging cold spray (CS) technique for rapid and scalable production of FE without a need for high-temperature post-sintering. In this regard, micron-scale Tin (Sn) particles are directly written on a flexible polymer substrate (PET) by cold spraying under ambient conditions. The effect of CS process parameters on the resultant coatings is comprehensively characterized in terms of microstructure, film thickness, electrical conductivity, linewidth, and adhesion strength. The resulting electrodes show excellent electrical conductivity (6.98 x 105 S m-1), adhesion strength, long-term stability, and flexibility without significant conductivity loss after 1000 bending cycles. By leveraging the CS operational settings, a resistive macro-heater (12 x 15 cm2) and an LED circuit (2.5 cm x 18 cm) are fabricated to demonstrate the applicability of the CS in printed FE. Moreover, to address the low-spatial reso-lution of CS writing, a case study on sequential CS and femtosecond laser machining is performed, which further led to ultra-high resolution (i.e., 30 mu m linewidth) custom-designed flexible electrodes. Thus, the present study reveals the immense potential of the CS technique for rapid and scalable production of FE without the need for post-sintering.Öğe Effect of fabric properties on solar behavior of curtains(İdris Karagöz, 2026) Bayar, Güler; Ruzgar, Duygu Gazioglu; Parın, Fatma Nur; Yıldırım, KenanIn this study, we examined how fabric construction, color, and yarn structural parameters affect the solar, ultraviolet (UV), and light transmittance, reflection and absorption properties, as well as the openness ratio of fabric curtains. Panama, 2/1 twill, 3/1 twill, and plain weave fabrics were produced. Using UV/VIS/NIR instruments, we measured the solar properties of all fabrics, calculating their transmittance (solar, light, and UV), reflection (solar and light), absorption (solar and light), and openness ratio. It was found that all solar properties were varied with fabric construction, yarn structure, and color. Solar, light, and UV transmittance values were the most affected by the weft and warp density, and an inverse ratio was found between them. The second major effect came from yarn dullness, which showed an inverse relationship with the transmittance values. Fabric color had the strongest effect on solar and light reflection, with darker colors producing lower reflection levels, while density and yarn dullness also influenced reflection and showed a direct relationship with reflection levels. The effects of fabric texture and yarn structure on reflection were low. The solar absorption rate was most affected by the color parameter, and it was observed that the absorption value increased as the color changed to be darker. The results also showed that fabric density strongly and inversely affected the openness ratio.Öğe Highly Flexible, Conductive, and Antibacterial Surfaces Toward Multifunctional Flexible Electronics(Korean Soc Precision Eng, 2024) Ruzgar, Duygu Gazioglu; Akin, Semih; Lee, Seungjun; Walsh, Julia; Lee, Hyowon Hugh; Jeong, Young Hun; Jun, Martin Byung-GukConductive metallization of polymer surfaces, owing to the integration of unique features of dissimilar materials (i.e., polymer + metal), is becoming the central focus in flexible polymer electronics. However, fabrication of multifunctional surfaces on polymers in a high-throughput and robust manner at ambient conditions remains challenging. In this study, we employ the cold spray (CS) particle deposition technique to produce multifunctional hybrid surfaces on a flexible polymeric substrate (PET) toward flexible electronics. In this regard, soft metal particles (Sn), are deposited on the polymer surface as an interlayer followed by the over-coating of hard metal (Cu) film to create hybrid (Sn + Cu) surfaces. Studies on microstructure, adhesion strength, and water contact angle are conducted to characterize the resulting surface structure. By leveraging the optimum CS settings, multifunctional surfaces with promising electrical conductivity (5.96 x 10(5) S.m(-1)), flexibility, adhesive strength, and hydrophobicity (contact angle approximate to 122 degrees) were achieved. Moreover, the antibacterial performance of the surface is confirmed by the in vitro antibacterial tests in a manner that > 99% of the bacteria were inhibited. This work provides a promising strategy for high-throughput manufacturing of multifunctional surfaces (flexible + conductive + antibacterial surfaces) toward multifunctional flexible electronics.Öğe Tailored-Biomaterials Based Potential Strategies for Cardiovascular Disease(Discovery Medicine, 2024) Bhullar, Sukhwinder K.; Mondal, Haimanti; Thomas, John; Ruzgar, Duygu Gazioglu; Chandrasekaran, Natarajan; Mukherjee, Amitava; Willerth, Stephanie M.Cardiovascular disease is a significant health concern worldwide, and varied effective treatment and prevention methods have been developed. Among these, tailored biomaterials-based strategies such as stents, scaffolds, patches, and drug delivery systems have emerged as a promising avenue. These devices are designed to match the mechanical and biological mechanisms of the cardiovascular system, ensuring optimal performance and compatibility. By effectively treating or preventing cardiovascular diseases, these devices have the potential to improve patient health outcomes significantly. They can restore blood flow by addressing blocked arteries and regenerate damaged cardiac tissue by delivering bioactive agents or cells directly to the affected area in a targeted, sustained, and controllable manner. Therefore, the objective of this article is to summarize the available evidence on these tailored biomaterial-based tunable cardiovascular devices. This knowledge can help to transform cardiovascular medicine for the treatment or prevention of cardiovascular disease and restore cardiac function to improve patients' quality of life.
