•Simple and easy surface modification method on laser induced graphene (LIG) through acetic acid treatment.•Conductivity enhancement of LIG towards even distribution of catalytic metal nanoparticles ...and higher sensitivity.•High charge transfer resistance towards electrochemical sensor with low detection limit.•Applicable to various sweat-based electrochemical sensors for medical and healthcare applications.
Porous laser-induced graphene (LIG) is an attractive and promising carbon material for electrochemical applications because it can immobilize various proteins, such as enzymes, antibodies, and receptors. However, poor inherent electrical properties caused by low surface conductivity is still a critical drawback for various applications. Here, we have proposed a surface modification method for the LIG electrode using acetic acid treatment via facile and practicable dipping technique. This simple acetic acid treatment dramatically increased the ratio of carbon-carbon bonds which effectively increased conductivity and decreased sheet resistance. In other words, acetic acid additionally reduced carbohydrate functional groups. Importantly, these unique properties also facilitated the stable and uniform dispersion of highly catalytic Pt nanoparticles (PtNPs) on LIG by avoiding the concentration of electric field on nanoparticles that can cause aggregation during electrodeposition. Finally, chitosan-glucose oxidase (GOx) composite was successfully immobilized onto the LIG/PtNPs electrode to fabricate a sweat glucose biosensor. The as-prepared LIG/PtNPs electrode exhibited a high sensitivity of 4.622 μA/mM as well as an ultra-low limit of detection (signal to noise ratio is 3) which was less than 300 nM and dynamic linear range up to 2.1 mM. Furthermore, we tested the variation of blood glucose level before and after meal using the amperometric response of the sensor which demonstrates the commercial potential of this unique sweat glucose biosensor.
We experimentally investigated the impact dynamics of a water drop on oil-infused nanostructured surfaces using high-speed microscopy and scalable metal oxide nano surfaces. The effects of physical ...properties of the oil and impact velocity on complex fluid dynamics during drop impact were investigated. We show that the oil viscosity does not have significant effects on the maximal spreading radius of the water drop, while it moderately affects the retraction dynamics. The oil viscosity also determines the stability of the infused lubricant oil during the drop impact; i.e., the low viscosity oil layer is easily displaced by the impacting drop, which is manifested by a residual mark on the impact region and earlier initiation of prompt splashing. Also, because of the liquid (water)–liquid (oil) interaction on oil-infused surfaces, various instabilities are developed at the rim during impact under certain conditions, resulting in the flower-like pattern during retraction or elongated filaments during spreading. We believe that our findings will contribute to the rational design of oil-infused surfaces under drop impact conditions by illuminating the complex fluid phenomena on oil-infused surfaces during drop impact.
With the increasing need for particulate matter (PM) monitoring, the demand for light-scattering sensors that allow for real-time measurements of PM is increasing. This light-scattering method ...involves irradiating light to the aerosols in the atmosphere to analyze the scattered light and measure mass concentrations. Humidity affects the measurement results. The humidity in an outdoor environment may exist as gas or steam, such as fog. While the impact of humidity on the light-scattering measurement remains unclear, an accurate estimation of ambient PM concentration is a practical challenge. Therefore, this study investigated the effects of humidity on light-scattering measurements by analyzing the variation in the PM concentration measured by the sensor when relative humidity was due to gaseous and steam vapor. The gaseous humidity did not cause errors in the PM measurements via the light-scattering method. In contrast, steam humidity, such as that caused by fog, resulted in errors in the PM measurement. The results help determine the factors to be considered before applying a light-scattering sensor in an outdoor environment. Based on these factors, directions for technological development can be presented regarding the correction of measurement errors induced by vapor in outdoor environments.
In response to global warming, researchers worldwide are actively investigating various techniques and institutional frameworks to reduce the emission of greenhouse gases. Despite numerous life cycle ...assessment (LCA) studies indicating that global warming effects due to lifetime energy consumption are the greatest in the building operation stage, the absence of a standard global warming potential (GWP) report based on building energy usage makes it difficult to examine realistic GWP reduction directions. In South Korea, energy data for numerous buildings were collected through the Building Energy Efficiency Certification (BEEC) for several years, with data from apartment buildings receiving the most attention. GWP emissions were evaluated using the data through Green Standard for Energy and Environmental Design LCA. Here, we developed a model for apartment buildings to assess mutual propriety for GWP emissions (E) and energy effective area ratio (R
) during building operation to support the reduction of GWP emissions caused by lifetime operational energy consumption resulting from planning and design. We collected apartment BEEC data and used them to calculate the energy effective area ratio and GWP emissions of each building, which were then classified by energy use and source. Linear regression analysis was performed between R
and E for each classification, and the derived regression equation was developed as a GWP assessment model for apartments. The applicability of the proposed model was examined through a case study, which confirmed that the model can be used to determine design directions for reducing GWP emissions for every energy in apartments.
Studies of the continuity of psychopathology symptoms mainly involved the traditional conceptualization that mental disorders are discrete entities. However, high comorbidity rates suggest a few ...transdiagnostic factors that underlie individual disorders. Therefore, the present study examined the validity of transdiagnostic factors in predicting homotypic and heterotypic continuity of comorbidity classes across two waves in a nationally representative sample. We conducted a latent transition analysis to investigate how transdiagnostic factors differentially affect the transition probabilities of comorbidity classes across time. Results found a notable predictive validity of transdiagnostic factors: (a) internalizing strongly predicted the stability of the internalizing class and transition from the externalizing class to internalizing class, and (b) externalizing predicted the transition from the internalizing class to externalizing class. The study also found a more dynamic prediction pattern leading to equifinality and multifinality of psychopathology symptoms. The findings suggest that transdiagnostic factors can provide information on how individuals' symptom manifestations change over time, highlighting the potential benefits of incorporating transdiagnostic factors into assessment, treatment, and prevention.
Given the increasingly serious nature of environmental problems, many countries have recently declared carbon neutrality policies and expended efforts to implement them. The domestic building ...industry aims to reduce its environmental impact using life-cycle assessments (LCAs) of buildings according to the Green Standard for Energy and Environmental Design. However, it is difficult to perform efficient LCAs because the required quantity takeoff process is complex, and the quantity takeoff sheet may not exist during the building’s design phase. In this study, 21 building LCAs were used to simplify and improve the efficiency of the proposed method and enable building LCAs even when there was no quantity takeoff sheet. Furthermore, a standard quantity database of building materials was constructed based on the analysis of the input quantities of building materials per unit area, and the apartment buildings LCA method was proposed using this database. The input quantities of building materials were analyzed using the probabilistic analysis technique. The probability distribution was derived using Monte Carlo simulations, and the goodness-of-fit was verified. Finally, the reliability of the proposed building LCA method was verified using a case study.
This study explores the visual content posted by far-right populist parliamentarians in Brazil, asking how “the people” are represented through imagery. Scholars have previously argued that populists ...have failed to foster the voice of “the people” in Latin America, but have they also failed to signify and cultivate an authentic visual representation of them? To answer this question, we collected the social media imagery posted by federal deputies of the 56th Legislature, a period characterized as one of illiberal backlash in Brazil. We employed visual analytics as a method of data analysis, demonstrating that clustering images according to their color similarities facilitates the study of key themes of populist communication, namely: the leader’s bodily performance, nationalism, the “enemy,” and “the people.” Besides this methodological contribution, our findings suggest that parliamentarians played a crucial role in enabling and sustaining far-right populist discourses. These politicians defined “the people” solely through the battles set in motion at the level of political affiliations. The voices of those claimed to be represented by them were diluted in visuals of mass demonstrations, which provided the primary occasion for their incorporation into populist communication.
The impacts of concrete on global warming through its use in structures such as buildings and infrastructure must be identified and better understood, as concrete is known to have a very high global ...warming potential (GWP). However, in contrast with ordinary on-site constructed reinforced concrete, GWPs of off-site factory-made prefabricated concrete products such as precast concrete (PC) and concrete piles that are widely used in construction are rarely evaluated, owing to the complicated manufacturing processes that make the determination of greenhouse gas emission difficult. In this study, the embodied life cycle GWPs were derived for PC and pretensioned spun high-strength concrete (PHC) piles to enable precise assessment of the global warming impact of concrete structures and the concrete industry of Korea. The determined embodied GWPs of PC and PHC piles were 1.77 × 10−1 kg CO2 eq/kg and 1.87 × 10−1 kg CO2 eq/kg, respectively. As a result, both prefabricated concrete products were determined to have high GWP due to input materials, such as cement rebars, while the GWP contributions of the off-site prefabrication processes were low. Moreover, the embodied GWPs of both prefabricated concrete products were significantly higher than those of ordinary reinforced concrete, and the impact of both products on global warming was found to be approximately 4% of the impact of the Korean concrete industry. This indicates that it is necessary to consider the impacts of the PHC pile and PC industries when assessing the impacts of greenhouse gas occurring in the concrete industry at the national level. It is expected that these findings will be widely used to obtain a more accurate assessment of the impact of concrete structures and industry on global warming.
The heat dissipation of a metal heat sink for passive cooling can be enhanced by surface modifications to increase its thermal emissivity, which is reflected by a darker surface appearance. In this ...study, copper electrodeposition followed by heat treatment was applied to a copper substrate. The heat treatment formed a nanoporous oxide layer containing CuO and Cu2O, which has a dark blackish color and therefore increased the thermal emissivity of the surface. The heat dissipation performance was evaluated using the sample as a heat sink for an LED module. The surface-treated copper heat sink with a high thermal emissivity oxide layer enhanced the heat dissipation of the LED module and allowed it to be operated at a lower temperature. With an increase in the heat treatment, the thermal emissivity increases to 0.865, but the thermal diffusivity is lower than the copper substrate by ~12%. These results indicate that the oxide layer is a thermal barrier for heat transfer, thus optimization between the oxide thickness and thermal emissivity is required by evaluating heat dissipation performance in operating conditions. In this study, an oxide layer with an emissivity of 0.857 and ~5% lower thermal diffusivity than the copper substrate showed the lowest LED operating temperature.
•Copper-based nano-engineered water repellent condensers were introduced.•High-speed microscopy was applied to characterize the condensation behaviors.•Condensation heat transfer performance was ...investigated with a developed model.•The heat transfer performance rapidly decreased on hydrophobic or oil-infused surfaces.•After 300min, superhydrophobic condensers provided ∼60% higher performance than hydrophobic or oil-infused ones.
We report the microscopic condensation behaviors and resulting heat transfer performance of scalable Cu-based water repellent surfaces with different wetting characteristics including hydrophobic (HPo), superhydrophobic (SHPo) and oil-infused superhydrophobic (Oil-SHPo). The overall heat transfer coefficient and the heat transfer rate through an individual droplet are investigated on horizontally-placed surfaces using the humidity and temperature controlled high speed microscopy combined with thermal network based model. The results show that the average heat transfer rate through an individual droplet is about an order of magnitude smaller on SHPo than on HPo or Oil-SHPo mainly due to smaller droplet radius and higher contact angle. However the investigated SHPo can provide a high number density of condensates throughout the entire measurement via coalescence-induced jumping, while HPo or Oil-SHPo rapidly loses their number density during the droplet coalescence which makes the suggested SHPo a promising condenser for long term use. After ∼300min, the overall heat transfer coefficient of the suggested SHPo becomes ∼60% higher than that of HPo and Oil-SHPo. This work clarifies the heat transfer performance of water repellent condensers with different wetting characteristics, and helps develop optimized condensers.
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