Removal Efficiency of Bottom Ash and Sand Mixtures as Filter Layers for Fine Particulate Matter.

Permeable pavement is a technology that allows rainwater to infiltrate into the pavement. Permeable pavements not only help reduce surface runoff by allowing rainwater to infiltrate into the pavement, but also improve water quality with the filter layer that removes particulate matter pollutants. This study evaluated the particulate matter removal efficiency of bottom ash-sand mixtures as filter layers for removing fine (≤10 µm) or ultrafine (≤2.5 µm) particulate matter in the laboratory. Five filter media were tested: silica sand, bottom ash, and bottom ash-sand mixtures with 30:70, 50:50, and 70:30 ratios. The mixed filters exhibited more consistent and stable particulate matter removal efficiency over time than either the uniform sand or bottom ash filter. The 50:50 bottom ash-sand mixture demonstrated removal rates of 58.05% for 1.8 µm particles, 93.92% for 10 µm particles, and 92.45% for 60 µm particles. These findings highlight the potential of bottom ash-sand mixtures as effective filter media for removing PM10 road dust, although field validation with actual pavement systems is necessary.

Reduction of Structural Defects in the GaSb Buffer Layer on (001) GaP/Si for High Performance InGaSb/GaSb Quantum Well Light-Emitting Diodes.

Monolithic integration of GaSb-based optoelectronic devices on Si is a promising approach for achieving a low-cost, compact, and scalable infrared photonics platform. While tremendous efforts have been put into reducing dislocation densities by using various defect filter layers, exploring other types of extended crystal defects that can exist on GaSb/Si buffers has largely been neglected. Here, we show that GaSb growth on Si generates a high density of micro-twin (MT) defects as well as threading dislocations (TDs) to accommodate the extremely large misfit between GaSb and Si. We found that a 250 nm AlSb single insertion layer is more effective than AlSb/GaSb strained superlattices in reducing both types of defects, resulting in a 4× and 13× reduction in TD density and MT density, respectively, compared with a reference sample with no defect filter layer. InGaSb quantum well light-emitting diodes were grown on the GaSb/Si templates, and the effect of TD density and MT density on their performance was studied. This work shows the importance of using appropriate defect filter layers for high performance GaSb-based optoelectronic devices on standard on-axis (001) Si via direct epitaxial growth.

Anti-influenza Activity of Povidone-Iodine-Integrated Materials.

Personal protective equipment (PPE), including medical masks, should be worn for preventing the transmission of respiratory pathogens via infective droplets and aerosols. In medical masks, the key layer is the filter layer, and the melt-blown nonwoven fabric (NWF) is the most used fabric. However, the NWF filter layer cannot kill or inactivate the pathogens spread via droplets and aerosols. Povidone-iodine (PVP-I) has been used as an antiseptic solution given its potent broad-spectrum activity against pathogens. To develop PPE (e.g., medical masks) with anti-pathogenic activity, we integrated PVP-I into nylon-66 NWF. We then evaluated its antiviral activity against influenza A viruses by examining the viability of Madin-Darby canine kidney (MDCK) cells after inoculation with the virus strains exposed to the PVP-I-integrated nylon-66 NWF. The PVP-I nylon-66 NWF protected the MDCK cells from viral infection in a PVP-I concentration-dependent manner. Subsequently, we found to integrate PVP-I into nylon-66 and polyurethane materials among various materials. These PVP-I materials were also effective against influenza virus infection, and treatment with PVP-I nylon-66 NWF showed the highest cell survival among all the tested materials. PVP-I showed anti-influenza A virus activity when used in conjunction with PPE materials. Moreover, nylon-66 NWF integrated with PVP-I was found to be the best material to ensure anti-influenza activity. Therefore, PVP-I-integrated masks could have the potential to inhibit respiratory virus infection. Our results provide new information for developing multi-functional PPEs with anti-viral activity by integrating them with PVP-I to prevent the potential transmission of respiratory viruses.

Double-Layered Strategy for Broadband Photomultiplication-Type Organic Photodetectors and Achieving Narrowband Response in Violet, Red, and Near-Infrared Light.

Broadband photomultiplication-type organic photodetectors (PM-OPDs) were prepared with PMBBDT:PY3Se-2V (1:1, wt/wt) as the absorbing layer (AL) and PC71BM:P3HT (100:5, wt/wt) as the photomultiplication layer (PML) on the basis of the sandwich structure. The incident photons from ultraviolet light to the near-infrared region can be harvested by AL. The rather less P3HT in PML can produce plenty of isolated hole traps with P3HT surrounded by PC71BM; the electron tunneling injection induced by trapped holes near the Ag electrode can lead to the photomultiplication (PM) phenomenon. The performance of PM-OPDs can be effectively improved by optimizing the AL thickness. The optimal PM-OPDs exhibit a broad spectral response from 300 to 1050 nm as well as an external quantum efficiency (EQE) of 5800% at 340 nm at 10 V bias, along with a specific detectivity (D*) of 3.78 × 1013 Jones. The spectral response of PM-OPDs is controlled by the trapped-hole distribution near the Ag electrode, primarily originating from the photogenerated holes in AL. To further optimize the spectral response of PM-OPDs, the optical filter layer (OFL) was used to manipulate light field distribution in AL. The violet, red, and near-infrared-light PM-OPDs were developed by employing different OFLs.

Evaluation of survival rates of airborne microorganisms on the filter layers of commercial face masks.

After the WHO designated COVID-19 a global pandemic, face masks have become a precious commodity worldwide. However, uncertainty remains around several details regarding face masks, including the potential for transmission of bioaerosols depending on the type of mask and secondary spread by face masks. Thus, understanding the interplay between face mask structure and harmful bioaerosols is essential for protecting public health. Here, we evaluated the microbial survival rate at each layer of commercial of filtering facepiece respirators (FFRs) and surgical masks (SMs) using bacterial bioaerosols. The penetration efficiency of bacterial particles for FFRs was lower than that for SMs; however, the microbial survival rate for all tested masks was >13%, regardless of filtration performance. Most bacterial particles survived in the filter layer (44%-77%) (e.g., the core filtering layer); the outer layer also exhibited significant survival rates (18%-29%). Most notably, survival rates were determined for the inner layers (<1% for FFRs, 3%-16% for SMs), which are in contact with the respiratory tract. Our comparisons of the permeability and survival rate of bioaerosols in each layer will contribute to bioaerosol-face mask research, while also providing information to facilitate the establishment of a mask-reuse protocol.

RGB-IR Cross Input and Sub-Pixel Upsampling Network for Infrared Image Super-Resolution.

Deep learning-based image super-resolution has shown significantly good performance in improving image quality. In this paper, the RGB-IR cross input and sub-pixel upsampling network is proposed to increase the spatial resolution of an Infrared (IR) image by combining it with a color image of higher spatial resolution obtained with a different imaging modality. Specifically, this is accomplished by fusion of the features map of two RGB-IR inputs in the reconstruction of an infrared image. To improve the accuracy of feature extraction, deconvolution is replaced by sub-pixel convolution to upsample image in the network. Then, the guided filter layer is introduced for image denoising of IR images, and it can preserve the image detail. In addition, the experimental dataset, which is collected by us, contains large numbers of RGB images and corresponding IR images with the same scene. Experimental results on our dataset and other datasets demonstrate that the method is superior to existing methods in accuracy and visual improvement.

[Removal of High Concentration of Iron, Manganese and Ammonia Nitrogen from Low Temperature Groundwater Using Single Bio-filter].

A pilot-scale bio-filter was constructed for the removal of high concentrations of iron (TFe 9.0-12.0 mg·L-1, Fe(Ⅱ) 6.5-8.0 mg·L-1), manganese (1.9-2.1 mg·L-1), and ammonia nitrogen (1.4-1.7 mg·L-1) simultaneously from low temperature (5-6℃) groundwater in a plant. The results showed that iron was removed at the beginning of the bio-filter start-up, and manganese and ammonia nitrogen were removed on day 72 and day 75, respectively. The start-up period was influenced by the culture temperature and the raw water quality. For higher filtration rates, the removal of manganese was lower. When the filtration rate was more than 1.0 m·h-1, the maximum removal of manganese was about 3.0 mg·L-1. Manganese was the limiting factor for the increase of filtration rate, and the maximum filtration rate of the single bio-filter was 4.5 m·h-1. When the filtration rate was less than 6.0 m·h-1, the removal of ammonia nitrogen was about 1.5 mg·L-1, which was not affected by the filtration rate. Dissolved oxygen (DO) deficiency led to failure with the removal of more ammonia nitrogen. The required thickness of the bio-filter required for purification increased as the concentration of manganese and ammonia nitrogen increased when DO was sufficient. The removed iron, manganese, and ammonia nitrogen move to the depth of the filter layer, and there will be "manganese dissolution" when the filtration rate is increased. Iron and ammonia nitrogen in the filter layer can be oxidized and removed simultaneously. Manganese is oxidized and removed after the iron and ammonia nitrogen. The effective oxidation and removal section of manganese, iron, and ammonia nitrogen are obviously graded.