We developed a novel solar steam generator (SSG) with high solar conversion efficiency and excellent salt resistance. A CO2 laser was used to convert the surface of basswood to graphitic carbon ...layers (GCL), and various grid patterns of GCL were created on wood. The low thermal conductivity of wood suppressed heat loss to bulk water, and the presence of the grooves in the grid increased the evaporation rate by increasing the surface area to absorb more sunlight. In addition, the supply of bulk water through the grooves endowed the SSG with salt resistance and self-regeneration properties. The salt resistance was maintained in a 20-wt % NaCl solution for the duration of the experiment (2 weeks), which indicates that the developed SSG can be used in saline water for long-term operation.
Face masks are used to protect the wearer from harmful external air and to prevent transmission of viruses from air exhaled by potentially infected wearers to the surrounding people. In this study, ...we examined the potential utility of masks for collecting viruses contained in exhaled breath and detected the collected viruses via various molecular tests. Using KF94 masks, the inner electrostatic filter was selected for virus collection, and an RNA extraction protocol was developed for the face mask. Virus detection in worn mask samples was performed using PCR and rolling circle amplification (RCA) tests and four different target genes (N, E, RdRp, and ORF1ab genes). The present study confirmed that the mask sample tests showed positive SARS-CoV-2 results, similar to the PCR tests using nasopharyngeal swab samples. In addition, the quantity of nucleic acid collected in the masks linearly increased with wearing time. These results suggest that samples for SARS-CoV-2 tests can be collected in a noninvasive, quick, and easy method by simply submitting worn masks from subjects, which can significantly reduce the hassle of waiting at airports or public places and concerns about cross-infection. In addition, it is expected that miniaturization technology will integrate PCR assays on face masks in the near future, and mask-based self-diagnosis would play a significant role in resolving the pandemic situation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Organic photovoltaics are an important part of a next‐generation energy‐harvesting technology that uses a practically infinite pollutant‐free energy source. They have the advantages of light weight, ...solution processability, cheap materials, low production cost, and deformability. However, to date, the moderate photovoltaic efficiencies and poor stabilities of organic photovoltaics impede their use as replacements for inorganic photovoltaics. Recent developments in bulk‐heterojunction organic photovoltaics mean that they have almost reached the lower efficiency limit for feasible commercialization. In this review article, the recent understanding of the ideal bulk‐heterojunction morphology of the photoactive layer for efficient exciton dissociation and charge transport is described, and recent attempts as well as early‐stage trials to realize this ideal morphology are discussed systematically from a morphological viewpoint. The various approaches to optimizing morphologies consisting of an interpenetrating bicontinuous network with appropriate domain sizes and mixed regions are categorized, and in each category, the recent trends in the morphology control on the multilength scale are highlighted and discussed in detail. This review article concludes by identifying the remaining challenges for the control of active layer morphologies and by providing perspectives toward real application and commercialization of organic photovoltaics.
The morphology of the bulk‐heterojunction photoactive layer critically influences charge‐carrier dynamics and therefore the overall photovoltaic performance of organic photovoltaics. The morphological issues reported so far are discussed and future directions toward further optimization are suggested.
Atmospheric aerosols are suspended particulate matter of varying composition, size, and mixing state. Challenges remain in understanding the impact of aerosols on the climate, atmosphere, and human ...health. The effect of aerosols depends on their physicochemical properties, such as their hygroscopicity, phase state, and surface tension. These properties are dynamic with respect to the highly variable relative humidity and temperature of the atmosphere. Thus, experimental approaches that permit the measurement of these dynamic properties are required. Such measurements also need to be performed on individual, submicrometer-, and supermicrometer-sized aerosol particles, as individual atmospheric particles from the same source can exhibit great variability in their form and function. In this context, this review focuses on the recent emergence of atomic force microscopy as an experimental tool in physical, analytical, and atmospheric chemistry that enables such measurements. Remaining challenges are noted and suggestions for future studies are offered.
Currently, the impact of various phase states of aerosols on the climate is not well understood, especially for submicrometer sized aerosol particles that typically have extended lifetime in the ...atmosphere. This is largely due to the inherent size limitations present in current experimental techniques that aim to directly assess the phase states of fine aerosol particles. Herein we present a technique that uses atomic force microscopy to probe directly for the phase states of individual, submicrometer particles by using nanoindentation and nano-Wilhelmy methodologies as a function of relative humidity (RH) and ambient temperature conditions. When using these methodologies for substrate deposited individual sucrose particles, Young’s modulus and surface tension can be quantified as a function of RH. We show that the force profiles collected to measure Young’s modulus and surface tension can also provide both qualitative and quantitative assessments of phase states that accompany solid, semisolid, and liquid particle phases. Specifically, we introduce direct measurements of relative indentation depth and viscoelastic response distance on a single particle basis at a given applied force to quantitatively probe for the phase state as a function of RH and corresponding viscosity. Thus, we show that the three phase states and phase state transitions of sucrose can be identified and ultimately propose that this technique may also be used to study other atmospherically relevant systems.
For efficient electrochemical catalysts, several molecular-scale descriptors have been proposed for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Various descriptors of ...perovskite catalysts have been proposed successfully for understanding either ORR or OER, but previous studies are insufficient to explain and thus boost up both ORR and OER simultaneously due to obstacles such as many different chemical compositions, structures, and metal orbital bands. Therefore, we investigate ORR/OER activities as a function of only oxygen vacancy concentration in perovskite oxides of Sm0.5Sr0.5CoO3−δ (SSC) to check the close relationship between delta (δ) and the electronic structure. Interestingly, the improved performance of both ORR and OER is explained by the change in the oxidation state of the transition metal caused by the increase in oxygen vacancies. Unfortunately, most previous research studies have focused on the effect of only oxygen vacancy (δ) on responsiveness. To confirm this, we performed density functional theory (DFT) analysis to find the more dominant factor on whether the activity descriptor is either δ or oxidation states of transition metals. The DFT analysis reveals that the ORR and OER activities of SSC are simultaneously improved by the reduced gap between d- and p-band centers (ΔE d–p) caused by the raised d-band center (M d). X-ray absorption spectroscopy has provided the exact electronic states of all the transition metals. Here, we report that an important factor of ORR/OER is affected only by the oxidation state of the transition metal in the perovskite oxide, not by the oxygen vacancy concentration.
Image search systems could be endangered by adversarial attacks and data perturbations. The image retrieval system can be compromised either by distorting the query or hacking the ranking system. ...However, existing literature primarily discusses attack methods, whereas the research on countermeasures to defend against such adversarial attacks is rare. As a defense mechanism against the intrusions, quality assessment can complement existing image retrieval systems. “GuaRD” is proposed as an end-to-end framework that uses the quality metric as a weighted-regularization term. Proper utilization and balance of the two features could lead to reliable and robust ranking; the original image is assigned a higher rank while the distorted image is assigned a relatively lower rank. Meanwhile, the primary goal of the image retrieval system is to prioritize searching the relevant images. Therefore, the use of leveraged features should not compromise the accuracy of the system. To evaluate the generality of the framework, we conducted three experiments on two image quality assessment(IQA) benchmarks (Waterloo and PieAPP). For the first two tests, GuaRD achieved enhanced performance than the existing model: the mean reciprocal rank(mRR) value of the original image predictions increased by 61%, and the predictions for the distorted input query decreased by 18%. The third experiment was conducted to analyze the mean average precision (mAP) score of the system to verify the accuracy of the retrieval system. The results indicated little deviation in performance between the tested methods, and the score was not effected or slightly decreased by 0.9% after the GuaRD was applied. Therefore, GuaRD is a novel and robust framework that can act as a defense mechanism for data distortions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Despite receiving increasing attention during the last few decades, the production of microalgal biofuels is not yet sufficiently cost-effective to compete with that of petroleum-based conventional ...fuels. Among the steps required for the production of microalgal biofuels, the harvest of the microalgal biomass and the extraction of lipids from microalgae are two of the most expensive. In this review article, we surveyed a substantial amount of previous work in microalgal harvesting and lipid extraction to highlight recent progress in these areas. We also discuss new developments in the biodiesel conversion technology due to the importance of the connectivity of this step with the lipid extraction process. Furthermore, we propose possible future directions for technological or process improvements that will directly affect the final production costs of microalgal biomass-based biofuels.
We developed a 3D solar steam generator with the highest evaporation rate reported so far using a carbonized luffa sponge (CLS). The luffa sponge consisted of entangled fibers with a hierarchically ...porous structure; macropores between fibers, micro-sized pores in the fiber-thickness direction, and microchannels in the fiber-length direction. This structure remained after carbonization and played an important role in water transport. When the CLS was placed in the water, the microchannels in the fiber-length direction transported water to the top surface of the CLS by capillary action, and the micro-sized pores in the fiber-thickness direction delivered water to the entire fiber surface. The water evaporation rate under 1-sun illumination was 3.7 kg/m
/h, which increased to 14.5 kg/m
/h under 2 m/s wind that corresponded to the highest evaporation rate ever reported under the same condition. The high evaporation performance of the CLS was attributed to its hierarchically porous structure. In addition, it was found that the air temperature dropped by 3.6 °C when the wind passed through the CLS because of the absorption of the latent heat of vaporization. The heat absorbed by the CLS during water evaporation was calculated to be 9.7 kW/m
under 1-sun illumination and 2 m/s wind, which was 10 times higher than the solar energy irradiated on the same area (1 kW/m
).
Intracellular antibodies have become powerful tools for imaging, modulating and neutralizing endogenous target proteins. Here, we describe an optogenetically activated intracellular antibody ...(optobody) consisting of split antibody fragments and blue-light inducible heterodimerization domains. We expanded this optobody platform by generating several optobodies from previously developed intracellular antibodies, and demonstrated that photoactivation of gelsolin and β2-adrenergic receptor (β2AR) optobodies suppressed endogenous gelsolin activity and β2AR signaling, respectively.
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