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This paper addressed the challenges associated with the complexity, numerous parameters, computational resource demands, and slow processing speed of transformer fault identification models based on deep learning technologies. Sparse convolutional neural network (CNN) approach is proposed for identifying faults related to dissolved gases in oil. Leveraging an improved Gramian angular field, one‐dimensional fault samples are converted into two‐dimensional feature images and data augmentation is implemented to meet the input requirements of deep learning models. Building upon visual geometry group (VGG)19 and residual networks (ResNet)50 networks for fault diagnosis, sparsity techniques are introduced through pruning, the fusion of convolution layers and batch normalization layers, and parameter quantization. Numerical experiments and performance evaluations on dissolved gas in transformer oil fault data demonstrate that the proposed method effectively reduced model complexity, minimized parameter count, conserved computational resources, and improved processing speed while maintaining a considerable level of fault identification accuracy. This made it applicable to edge computing platforms characterized by small form factors and low power consumption in the power industry. [ABSTRACT FROM AUTHOR]

The frequency characteristics of lung sounds have great significance for noninvasive diagnosis of respiratory diseases. The rales in the lower respiratory tract region that can provide rich information about symptoms of respiratory diseases are not clear. In this paper, a three-dimensional idealized bifurcated lower respiratory tract geometric model, which contains 3rd to 13th generation (G3–G13) bronchi is constructed, where Re ∼ 10 1 - 10 3 , and then the large eddy simulation and volume of fluid are used to study the fluid flow characteristics. Ffowcs Williams and Hawkings model are subsequently used to study the frequency characteristics of rale of different generations of bronchi. The results showed that bronchial blockage and sputum movement will enhance the turbulence intensity and vortex shedding intensity of flow. The dominant frequency and highest value of sound pressure level (SPL) of rhonchi/moist crackles decrease with the increase of bronchial generation. The change rates of dominant frequency of rhonchi / moist crackles in adjacent generations were 5.0 ± 0.1 ~ 9.1 ± 0.2% and 3.1 ± 0.1 ~ 11.9 ± 0.3%, respectively, which is concentrated in 290 ~ 420 Hz and 200 ~ 300 Hz, respectively. The change rates of SPL of rhonchi/moist crackles were 8.8 ± 0.1 ~ 15.7 ± 0.1% and 7.1 ± 0.1 ~ 19.5 ± 0.2%, respectively, which is concentrated in 28 ~ 50 dB and 16 ~ 32 dB, respectively. In the same generation of bronchus (e.g., G8, G9) with the same degree of initial blockage, the dominant frequency and SPL of moist crackles can be 3.7 ± 0.2% and 4.5 ± 0.3% slightly higher than that of rhonchi, respectively. This research is conducive to the establishment of a rapid and accurate noninvasive diagnosis system for respiratory diseases. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has sparked a global interest in understanding the mechanism of transmission of bioaerosols in enclosed environments. Swift and accurate calculations of particle trajectories are crucial for predicting the diffusion of bioaerosols. The use of machine learning can expedite these calculations and predictions. However, research focusing on the use of machine learning methods for calculating bioaerosol trajectories remains scarce. A bioaerosol trajectory is a time series with long intervals and delays between different positions; certain machine learning models are well suited for handling time series data. Herein, we aimed to establish a new method we refer to as physics–machine learning (P–ML) that includes a machine learning model for calculating bioaerosol trajectories. To this end, we adopted a lightweight, single-layer long short-term memory (LSTM) model and used supervised learning with mean squared error as an evaluation metric for training. Our findings indicate that disregarding the turbulence diffusion enables us to train the LSTM model by a motion equation. Furthermore, the model accurately predicted trajectories while exhibiting some degree of transferability. However, when considering the turbulence diffusion of bioaerosol, the training data in P–ML method could not be generated using a motion equation with turbulence diffusion model (Discrete Random Walk model). To address this issue, we integrating the fluctuating velocity into the LSTM model input. Consequently, the predicted results were consistent with the motion equation. Our method exhibits considerable potential for expediting trajectory calculation and aiding in early warning and rapid design in enclosed environments. Copyright © 2023 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

OsMADS1 plays a vital role in regulating floret development and grain shape, but whether it regulates rice grain quality still remains largely unknown. Therefore, we used comprehensive molecular genetics, plant biotechnology, and functional omics approaches, including phenotyping, mapping-by-sequencing, target gene seed-specific RNAi, transgenic experiments, and transcriptomic profiling to answer this biological and molecular question. Here, we report the characterization of the 'Oat-like rice' mutant, with poor grain quality, including chalky endosperms, abnormal morphology and loose arrangement of starch granules, and lower starch content but higher protein content in grains. The poor grain quality of Oat-like rice was found to be caused by the mutated OsMADS1Olr allele through mapping-by-sequencing analysis and transgenic experiments. OsMADS1 protein is highly expressed in florets and developing seeds. Both OsMADS1-eGFP and OsMADS1Olr-eGFP fusion proteins are localized in the nucleus. Moreover, seed-specific RNAi of OsMADS1 also caused decreased grain quality in transgenic lines, such as the Oat-like rice. Further transcriptomic profiling between Oat-like rice and Nipponbare grains revealed that OsMADS1 regulates gene expressions and regulatory networks of starch and storage protein metabolisms in rice grains, hereafter regulating rice quality. In conclusion, our results not only reveal the crucial role and preliminary mechanism of OsMADS1 in regulating rice grain quality but also highlight the application potentials of OsMADS1 and the target gene seed-specific RNAi system in improving rice grain quality by molecular breeding. [ABSTRACT FROM AUTHOR]

A large amount of surgical smoke in electrosurgery seriously deteriorates the clean environment of the operating room and can potentially harm medical staff and patients. Exploring the distribution and removal of indoor particulate matter and selecting efficient ventilation patterns are effective ways to control harmful smoke. Therefore, in this study, we combined simulations and full-scale experiments to quantitatively explore the high-concentration spatial regions of particles and compared three ventilation patterns: vertical laminar airflow (VLAF), horizontal laminar airflow (HLAF), and hybrid ventilation, wherein unidirectional airflow (UDAF) was applied to the operating table along with peripheral mixing (UDAF + mixing). We found that simple laminar flow ventilation was significantly affected by the equipment layout and air change rate (air changes per hour; ACH), and the smoke particles were distributed in large amounts in the operating area and could not be removed completely. Conversely, hybrid ventilation can work effectively, and the optimal ACH is approximately 60, which can remove nearly 72% of smoke particles. The airflow distribution in the operating room is also an important factor affecting the distribution and removal of smoke particles. Therefore, medical staff should avoid prolonged exposure to areas with high particle concentrations and particle removal paths. [ABSTRACT FROM AUTHOR]

Salt–alkali stress threatens the resilience to variable environments and thus the grain yield of rice. However, how rice responds to salt–alkali stress at the molecular level is poorly understood. Here, we report isolation of a novel salt–alkali-tolerant rice (SATR) by screening more than 700 germplasm accessions. Using 93-11, a widely grown cultivar, as a control, we characterized SATR in response to strong salt–alkali stress (SSAS). SATR exhibited SSAS tolerance higher than 93-11, as indicated by a higher survival rate, associated with higher peroxidase activity and total soluble sugar content but lower malonaldehyde accumulation. A transcriptome study showed that cell wall biogenesis-related pathways were most significantly enriched in SATR relative to 93-11 upon SSAS. Furthermore, higher induction of gene expression in the cell wall matrix polysaccharide biosynthesis pathway, coupled with higher accumulations of hemicellulose and pectin as well as measurable physio-biochemical adaptive responses, may explain the strong SSAS tolerance in SATR. We mapped SSAS tolerance to five genomic regions in which 35 genes were candidates potentially governing SSAS tolerance. The 1,4-β-D-xylan synthase gene OsCSLD4 in hemicellulose biosynthesis pathway was investigated in details. The OsCSLD4 function-disrupted mutant displayed reduced SSAS tolerance, biomass and grain yield, whereas the OsCSLD4 overexpression lines exhibited increased SSAS tolerance. Collectively, this study not only reveals the potential role of cell wall matrix polysaccharides in mediating SSAS tolerance, but also highlights applicable value of OsCSLD4 and the large-scale screening system in developing SSAS-tolerant rice. [ABSTRACT FROM AUTHOR]

3D neural networks are widely used in real-world applications (e.g., AR/VR headsets, self-driving cars). They are required to be fast and accurate; however, limited hardware resources on edge devices make these requirements rather challenging. Previous work processes 3D data using either voxel-based or point-based neural networks, but both types of 3D models are not hardware-efficient due to the large memory footprint and random memory access. In this paper, we study 3D deep learning from the efficiency perspective. We first systematically analyze the bottlenecks of previous 3D methods. We then combine the best from point-based and voxel-based models together and propose a novel hardware-efficient 3D primitive, Point-Voxel Convolution (PVConv). We further enhance this primitive with the sparse convolution to make it more effective in processing large (outdoor) scenes. Based on our designed 3D primitive, we introduce 3D Neural Architecture Search (3D-NAS) to explore the best 3D network architecture given a resource constraint. We evaluate our proposed method on six representative benchmark datasets, achieving state-of-the-art performance with 1.8-23.7× measured speedup. Furthermore, our method has been deployed to the autonomous racing vehicle of MIT Driverless, achieving larger detection range, higher accuracy and lower latency. [ABSTRACT FROM AUTHOR]

Postoperative complications of gastrectomy for gastric cancer affect the efficacy of surgery. It is of clinical significance to identify high-risk patients with postoperative complications as early as possible. A total of 206 patients who underwent gastrectomy were enrolled in this study. Univariate and multivariate analyses were used to determine the risk factors for postoperative complications. The cutoff value and diagnostic accuracy of the C-reactive protein/albumin ratio were calculated by receiver operating characteristic curves. A total of 64 (31.1%) patients developed postoperative complications. Multivariate analysis confirmed that the C-reactive protein/albumin ratio on the first day after operation was an independent risk factor for postoperative complications (OR = 2.538, 95%CI: 1.346–4.785, P = 0.004). The cutoff value of the C-reactive protein/albumin ratio on the first day after operation was 2.105 calculated by receiver operating characteristic curves. Patients with a C-reactive protein/albumin ratio greater than 2.105 had a higher incidence of postoperative complications (43.2% vs 22.0%, P = 0.001) and longer postoperative hospital stay (15.3 ± 1.2 vs 13.0 ± 0.5, P = 0.042) than patients with less than 2.105. Patients with C-reactive protein/albumin ratio greater than 2.105 on the first day after operation are more likely to have postoperative complications. [ABSTRACT FROM AUTHOR]

Wear debris in lubrication oil provides important information for marine engine condition monitoring and faults diagnosis. Inductive sensors have been widely used to detect wear debris in lubrication oil. To improve the sensitivity, the inductive coil is always connected with a capacitor in parallel to form parallel LC resonance-sensing circuit. A previous study optimized the parallel resonance circuit by adjusting the excitation frequency. However, multiple parameters (namely, excitation signal, signal detection circuits, and signal-processing program, etc.) need to be adjusted accordingly for a series of the testing frequencies. To simplify the optimization, we propose a method based on adjusting the parallel capacitance in this work. The impedance (inductance and internal resistance) of the sensing coil and its variation induced by particles are first measured, which are the necessary parameters for establishing the function relationship between the parallel capacitance and the relative impedance variation. With the function relationship, the relative impedance variation is calculated directly, and the optimal capacitance is located at the highest absolute value of it. The experimental results for the ferrous and nonferrous particles match the calculation results well. Interestingly, the optimal capacitance for the nonferrous particle was larger than that of the ferrous particle. We speculate that the difference is generated due to the increased resistance induced by the eddy current effect. [ABSTRACT FROM AUTHOR]

Inductance detection is an important method for detecting wear debris in ship lubricating oil. Presently, an LCR (inductance, resistance, capacitance) meter is generally used to detect wear debris by measuring the inductance change of the sensing coil. When ferromagnetic debris passes through the sensing coil, a pulse will appear in the inductance signal. Previous studies have shown that the amplitude of the inductance pulse decreases significantly with the increase in the particles' velocity. Therefore, it is difficult to detect ferromagnetic debris with a high flow velocity using an LCR meter. In this paper, a novel method, high-frequency voltage acquisition (HFVA), is proposed to detect ferromagnetic debris. Different from previous methods, the wear debris was detected directly by measuring the voltage change of the sensing coil, while the synchronized sampling method was utilized to ensure the higher-frequency acquisition of the sensor output signal. The experimental results show that when the velocity of particles increased from 6 mm/s to 62 mm/s, the amplitude of the signal pulse obtained by HFVA decreased by only 13%, which was much lower than the 85% obtained by utilizing the LCR method. [ABSTRACT FROM AUTHOR]

Carcinogenic N-nitrosamines were recently found in the sartan family of drugs and caused many drug recalls. Both of their detection and quantification are therefore important. Methods reported for N-nitrosamine quantitation rely on the use of standards and are just applicable to simple N-nitrosamines. There is an urgent need to quantify N-nitrosamines derived from drugs with a complicated structure that lack standards. To tackle the issue, this study describes a novel absolute quantitation strategy for N-nitrosamines using coulometric mass spectrometry (CMS) without standards. In our approach, N-nitrosamine is first converted into electrochemically active hydrazine via zinc reduction under acidic condition and the resulting hydrazine can then be easily quantified using CMS. To validate our method, six simple N-nitrosamines, N-nitrosodiethylamine (NDEA), N-nitroso-4-phenylpiperidine (NPhPIP), N-nitrosodiphenylamine (NDPhA), N-nitrosodibutylamine (NDBA), N-nitrosodipropylamine (NDPA), and N-nitrosopiperidine (NPIP), were chosen as test samples, and they all were quantified with excellent measurement accuracy (quantitation error ≤1.1%). Taking this one step further, as a demonstration of the method utility, a drug-like N-nitrosamine, (R)-N-(2-(6-chloro-5-methyl-1′-nitroso-2,3-dihydrospiro-[indene-1,4′-piperidin]-3-yl)-propan-2-yl)-acetamide (VII), was also synthesized and successfully quantified using our method at 15 ppb level in a complex formulation matrix, following solvent extraction, N-nitrosamine isolation, and reductive conversion. Because of the feature of requiring no standards, CMS provides a simple and powerful approach for N-nitrosamine absolute quantitation and has great potential for analysis of other drug impurities or metabolites. [ABSTRACT FROM AUTHOR]

With the increasing demand for resources, the task of the geological survey is growing rapidly. The automatic geological drilling rig, which can improve the efficiency of the geological survey, has become the mainstream development direction. In this study, the hydraulic control system for the automatic screw up and screw down of an automatic drilling rig is studied. Through the establishment of mathematical models such as the four-way slide valve controlled asymmetric cylinder model, drill pipe thread stress model, and steel wire rope elastic model, the hydraulic valve is used to limit the pressure of the hydraulic cylinder, closed-loop control to control rotation speed, and power head floating to prevent screw damage and realize the automatic control of drill pipe up and down of a geological drilling rig. The hydraulic control system is simulated by AMESim software. The simulation model verifies the mathematical model. It is concluded that the maximum transient force of steel wire rope is caused by the elastic coefficient K of steel wire rope, but the magnitude is independent of K. The transient force is the periodic motion force. The displacement, velocity, and acceleration of load are periodic functions related to time. By installing a small flow load sensing valve, the displacement of an asymmetric hydraulic cylinder can be accurately controlled, and then, the displacement of the drilling rig powerhead can be controlled. The combined action of drill pipe speed and power head displacement is adopted, and the power head displacement is followed by PID control through the feedback value of the drill pipe speed, which can realize the automatic loading and unloading of drill pipe and reduce the damage of drill pipe screw during loading and unloading of drill pipe. The research results of this study can provide a theoretical reference and design basis for the follow-up development of an automatic drilling rig. [ABSTRACT FROM AUTHOR]

For the flat plastic parts with the size range of 200 to 1300 mm, the structural parameters decision model of injection mold gating system is established in this paper. Firstly, the relationship between the warpage and the structural parameters of gating system is fitted by Kriging model, and the minimum warpage is optimized by genetic algorithm (GA) to obtain the best structural parameters. Secondly, the best structural parameters of gating system corresponding to 16 groups of plastic parts are taken as samples, and the relationship between the structural parameters of gating system and the size parameters of plastic parts is established by Kriging model. In addition, K-means is used to reduce the number of the structural parameters of gating system from 5 to 2, in order to improve the accuracy of decision model. Finally, the size parameters of plastic parts are input to the decision model to obtain the structural parameters of gating system. Through the verification of mold flow analysis experiment, the structural parameters of gating system obtained by this method meet the design requirements and can effectively shorten the structural design cycle of injection mold. [ABSTRACT FROM AUTHOR]

Biosafety laboratories are critical in many fields. However, experimenters associated the infection risk from biological aerosols. In this study, by conducting experiments on the release and collection of bioaerosols within a typical BSL-2 + laboratory, the spatial distribution of bioaerosols was tracked. Numerical calculations were employed to obtain and visualize the airflow patterns and aerosol dispersion paths of four ventilation methods. The results indicated that equipment and tables led to uneven airflow distribution within the laboratory. The comparison results of the four evaluation indicators showed that the air age distribution of UU (Upward supply and upward return) mode and CD (Cross-supply and downward return) mode was superior, with air change efficiency values of 0.595 and 0.603, respectively. Additionally, the contaminant removal index of CD mode was 1.48, significantly higher than the other ventilation methods. The statistical results of the contaminant dispersion index also indicated that CD mode was most conducive to diluting aerosols in the spatial environment. The LD (lateral supply and downward return) mode may lead to airflow short-circuiting. The UD (upward supply and downward return) mode can provide balanced protection for laboratory. Overall, CD mode performed the best among the four ventilation methods, followed by UU mode. [Display omitted] • Aerosol distribution in BSL-2 + was tracked by experiment and numerical calculation. • The ventilation and air exchange were comprehensively evaluated by four indices. • Cross-supply airflow exhibits best air exchange efficiency as well as aerosol control. • Ventilation strategy should be customized based on variables laboratory environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • A technology was created by merging experimental data and machine learning. • A comprehensive comparison of eleven machine learning algorithms was performed. • ET and MLP excel in prediction, achieving R2 values of 0.954 and 0.904, respectively. • Interval prediction provides a range of predicted values, enhancing confidence. • Enhancing the model's robustness through perturbation analysis by introducing noise. Maintaining high ventilation rates in operating rooms (ORs) is critical to ensure the safety of healthcare professionals and patients. Yet, the significant energy consumption associated with ventilation systems is a growing global concern. While traditional approaches have predominantly focused on optimizing ventilation design, limited attention has been given to operational control strategies. This study aims to control ceiling air supply speed by exposure aerosol concentrations exhaled by the patient. It achieves this by integrating empirical data with machine learning (ML) models, effectively balancing the need for maintaining optimal ventilation conditions and ensuring a safe aerosol exposure concentration. Experimental results from a full-scale OR setup, manipulating ceiling air supply speed, respiratory flow rate, and surgical bed height, generated 81 datasets. These datasets served as the basis for assessing the performance of 11 ML models. Notably, the extra trees (ET) and multi-layer perceptron (MLP) models outperformed the others, exhibiting impressive coefficient of determination (R2) values of 0.954 and 0.904, respectively. Moreover, the models were further enhanced by assessing their robustness with Gaussian noise and interval prediction. This study presents a novel approach that holds significant relevance for the practical control of ventilation systems, particularly with regard to health and energy efficiency considerations. [ABSTRACT FROM AUTHOR]

Although it is clear that respiratory pathogens are transmitted through droplets and physical contact in Fangcang shelter hospitals (FSHs), the potential for long-range transmission is poorly understood (Offord, 2020; WHO, 2020), and the effective ventilation rate for epidemic prevention in large public spaces is also not yet known. We investigated the pathogen-laden aerosol aerodynamics for the first time in the FSH using a model bacteria indication of the pathogen, concurrently examining ventilation rates on their long-range transmission. The study found that aerosols with sizes smaller than 3.3 μm could facilitate the long-range transmission of pathogens. Poor ventilation results in an increase in contamination levels, but excessive ventilation (12 ACH) may trigger a diminishing return phenomenon of ventilation within the FSH, and worsen aerosol deposition. For this FSH, an ideal ventilation rate was close to 10 ACH, and pathogen-laden aerosols were reduced by 29.54% and 26.77% in the pollution zone and surveyed patient shelter block (PSB), respectively, compared to the design values. Our study contributes to cleaner production in the FSH, as well as to the sustainability of healthcare services and the environment. Some of the findings can be generalized to some extent for similar large public spaces. • First long-range transmission experiment with bioaerosol in large public scenarios. • Obtained aerodynamics of pathogen-laden aerosol for long-range transmission. • Investigating the effect of ventilation rates on aerosol long-range transmission. • Excessive ventilation can significantly worsen aerosol deposition. [ABSTRACT FROM AUTHOR]

Hybrid energy storage offers a new way to increase the renewable energy proportion (REP) of near-zero energy community energy system (NZECES). However, the optimization operation method of NZECES combining hybrid energy storage is not yet mature. Therefore, this paper proposes integrating electricity storage, heat storage and hydrogen storage into the NZECES, and conducting multi-time scale (MTS) operation optimization research. Firstly, a NZECES with electricity-heat-hydrogen storage is constructed. Secondly, a MTS optimization operation model of day-ahead scheduling, intra-day rolling, and real-time adjustment is established. Among them, the hourly scheduling scheme targeting the lowest daily operating cost is obtained through the optimization of the day-ahead stage. In the intra-day stage, the scheduling scheme with a time interval of 15 min is obtained by the rolling optimization. The operation scheme of electrical-related equipment with the minimum adjustment cost is obtained in the real-time stage. Finally, a NZEC with different building types is used as the energy supply object. The results show that compared to the traditional day-ahead scheduling scheme, the REP is increased by 3.6 % and the operation cost of the energy system is reduced by 5.3 % by using the MTS operation optimization method. • A near-zero energy community energy system with hybrid energy storage is constructed. • A multi-time scale operation scheme of day-ahead, intra-day, real-time is proposed. • The scheme can improve the renewable energy proportion and operation economy. [ABSTRACT FROM AUTHOR]

Several studies have novel distributed energy systems combining solar energy utilization and hybrid energy storage technology. However, the research on thermodynamic performance and optimization design of the novel system is still insufficient. Therefore, a novel distributed energy system uses a jacket water heat exchanger and a waste heat boiler to recover the waste heat of the internal combustion engine in turn and shares a water tank with the solar thermal collector in parallel. Then, the influence of different parameters on the thermodynamic performance of the system under variable working conditions is analyzed by the parametric analysis method. On this basis, an optimization design method considering the thermodynamic and economic performance of the novel system is proposed. The novel system is applied to a nearly zero-energy community with an electric vehicle charge load. The results show that the exergy efficiency, primary energy rate, and cost per unit supply area of the novel system in a typical year are 19.2%, 70.1%, and 5.4 $/m2, respectively. Therefore, the novel system is reliable and feasible in providing all kinds of energy to users. [ABSTRACT FROM AUTHOR]

The incidence of short-term complications after laparoscopic surgery for gastric cancer is higher. Whether ω-3 fish oil fat emulsion can reduce short-term complications of gastric cancer after laparoscopic surgery is controversial. The purpose of this study was to explore the effect of ω-3 fish oil fat emulsion on postoperative recovery of patients with gastric cancer after laparoscopic surgery. A total of 111 patients were included in this study. These patients were given parenteral nutrition for 5 day or more after surgery. We used univariate analysis and multivariate analysis to determine whether ω-3 fish oil fat emulsion could affect the incidence of short-term complications after gastric cancer laparoscopic surgery. The incidence of postoperative short-term complications in patients with parenteral nutrition supplemented with ω-3 fish oil fat emulsion was significantly lower than that in patients without ω-3 fish oil fat emulsion (12/51 VS 26/60, P = 0.027). ω-3 fish oil fat emulsion is an independent risk factor for short-term postoperative complications in patients with gastric cancer (OR = 0.393, CI:0.155-0.996, P = 0.049). In conclusion, the addition of ω-3 fish oil fat emulsion to parenteral nutrition after operation can effectively reduce the incidence of short-term complications in patients with gastric cancer after laparoscopic surgery. [ABSTRACT FROM AUTHOR]

Upper-room ultraviolet germicidal irradiation (UVGI) technology can potentially inhibit the transmission of airborne disease pathogens. There is a lack of quantitative evaluation of the performance of the upper-room UVGI for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) airborne transmission under the combined effects of ventilation and UV irradiation. Therefore, this study aimed to explore the performance of the upper-room UVGI system for reducing SARS-CoV-2 virus transmission in a hospital isolation environment. Computational fluid dynamics and virological data on SARS-CoV-2 were integrated to obtain virus aerosol exposure in the hospital isolation environment containing buffer rooms, wards and bathrooms. The UV inactivation model was applied to investigate the effects of ventilation rate, irradiation flux and irradiation height on the upper-room UVGI performance. The results showed that increasing ventilation rate from 8 to 16 air changes per hour (ACH) without UVGI obtained 54.32% and 45.63% virus reduction in the wards and bathrooms, respectively. However, the upper-room UVGI could achieve 90.43% and 99.09% virus disinfection, respectively, with the ventilation rate of 8 ACH and the irradiation flux of 10 μW cm−2. Higher percentage of virus could be inactivated by the upper-room UVGI at a lower ventilation rate; the rate of improvement of UVGI elimination effect slowed down with the increase of irradiation flux. Increase irradiation height at lower ventilation rate was more effective in improving the UVGI performance than the increase in irradiation flux at smaller irradiation height. These results could provide theoretical support for the practical application of UVGI in hospital isolation environments. • Performance of upper-room ultraviolet germicidal irradiation (UVGI) was studied. • Numerical models were validated by a bioaerosol experiment in an isolation ward. • Upper-room UVGI can achieve more than 90% virus disinfection in an isolation ward. • Percentage of virus inactivated by UVGI decreases as ventilation rate increases. • Irradiation height is more critical for disinfection under low ventilation rates. [ABSTRACT FROM AUTHOR]

With the ever-increasing demand for resources, the task of geological surveys has increased rapidly, and automated geological drilling rigs that can improve the efficiency of geological surveys have become the mainstream research direction. Automated geological drilling rigs can improve construction efficiency, reduce labor intensity, and effectively reduce construction accidents. During the construction of geological survey operations, accidents such as drill breakage, stuck drill, and equipment damage, which are easily caused by drill pipe impact, occur from time to time. Therefore, drill pipe impact dynamics is currently a hot topic in academic research, but there are few studies that combine automated geological drilling rigs with drill pipe impact. This article starts with the research on the hydraulic system of the power head of the automatic drilling rig and studies the dynamics of the damage of the power head of the drilling rig caused by the impact of the drill pipe by means of hydraulic valve torque limit and closed-loop control of the speed. The oil valve group reduces the reverse torsional impact of the drill pipe on the hydraulic motor. At the same time, the requirements for the selection and pressure setting of the relief valve in the buffer filling oil valve group are proposed. The natural frequency of the relief valve is not less than 20 Hz, and the pressure is set to the working pressure 1.25 times. The effects of shock with or without the buffer filling oil valve group and the oil supply line on the power head motor were compared. The research results of this paper can provide theoretical reference and design basis for subsequent development of automated drilling rigs. [ABSTRACT FROM AUTHOR]

Aerosol-to-hydrosol biological samplers have a low particle collection rate and aerosol-to-liquid efficiency owing to their airflow rate and geometry. The study develops a method to optimize the design of an aerosol-to-hydrosol bioaerosol sampler for better particle-collection efficiency. Four important performance parameters—particle size, nozzle angle, liquid container shape, and distance between nozzle and liquid surface—were optimized using the orthogonal design method. These parameters, along with the particle-capturing characteristics, were predicted using an approach based on computational fluid dynamics. Subsequently, this approach was used to test the bioaerosol's capture efficiency. A prototype based on the optimized geometrical design was 3D-printed and tested in a field experiment. The most optimal parameters were particle size = 10 µm; inverted cone shape; liquid-level–nozzle distance = 10 mm; and angle = 45°. Copyright © 2020 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Zeta potential of PDMS-liquid interface is an important parameter for generating electroosmotic flow in a PDMS microchannel. In this paper, the zeta potentials of a PDMS slab in contacting with electrolyte solutions were evaluated with an atomic force microscope (AFM). As a colloidal probe of the AFM approaches to the surface of a PDMS slab in an electrolyte solution, a force curve is obtained and used to calculate the zeta potential of the PDMS. The effects of the plasma treating time and the aging of the electrolyte solutions on the zeta potential of PDMS surfaces were examined. The experimental results show that the air plasma treating time does not change the zeta potential of PDMS appreciably. Furthermore, the decreased zeta potential of a plasma-treated PDMS in an electrolyte solution is due to liquid aging, not the PDMS itself. Such characteristics probed by AFM provide new understanding of the surface charges of PDMS in electrolyte solutions. [ABSTRACT FROM AUTHOR]

Model quantization is a widely used technique to compress and accelerate deep neural network (DNN) inference. Emergent DNN hardware accelerators begin to support flexible bitwidth (1–8 bits) to further improve the computation efficiency, which raises a great challenge to find the optimal bitwidth for each layer: it requires domain experts to explore the vast design space trading off accuracy, latency, energy, and model size, which is both time-consuming and usually sub-optimal. There are plenty of specialized hardware accelerators for neural networks, but little research has been done to design specialized neural networks optimized for a particular hardware accelerator. The latter is demanding given the much longer design cycle of silicon than neural nets. Conventional quantization algorithm ignores the different hardware architectures and quantizes all the layers in a uniform way. In this paper, we introduce the Hardware-Aware Automated Quantization (HAQ) framework which automatically determine the quantization policy, and we take the hardware accelerator's feedback in the design loop. Rather than relying on proxy signals such as FLOPs and model size, we employ a hardware simulator to generate the direct feedback signals to the RL agent. Compared with other conventional methods, our framework is fully automated and can specialize the quantization policy for different neural network architectures and hardware architectures. Our framework effectively reduced the latency by 1.4–1.95 × and the energy consumption by 1.9 × with negligible loss of accuracy compared with the fixed bitwidth (8 bits) quantization. Our framework reveals that the optimal policies on different hardware architectures (i.e., edge and cloud architectures) under different resource constraints (i.e., latency, energy and model size) are drastically different. We interpreted the implication of different quantization policies, which offer insights for both neural network architecture design and hardware architecture design. [ABSTRACT FROM AUTHOR]

Indoor fungal is of great significance for human health. The kernel-based extreme learning machine is employed to determine the most important parameters for predicting the concentration of indoor culturable fungi (ICF). For model training and statistical analysis, parameters that contained indoor or outdoor PM10 and PM2.5, RH, Temperature, CO2 and ICF were measured in 85 residential buildings of Baoding, China, from November 2016 to March 2017. The variable selection process contains four different cases to identify the optimal input combination. The results indicate that root mean square error of the optimal input combinations can be improved 5.6% from 1 to 2 input variables, while that could be only improved 1.9% from 2 to 3 input variables. However, considering both precision and simplicity, the combination of indoor PM10 and RH provides a more suitable selection for predicting the ICF. [ABSTRACT FROM AUTHOR]

Formaldehyde (CH 2 O) is the most common volatile organic pollutant in the indoor environment, which can directly cause respiratory system diseases of humans. As a new type of material, graphene-based single atom adsorbent has the advantages of large specific surface and high adsorption activity, which can provide a new direction for formaldehyde removal. In this paper, the adsorption characteristics of formaldehyde on graphene-based single atom adsorbents were investigated through density functional theory (DFT) calculations. According to the analysis of geometric structure, electron transfer and density of states (DOS), the adsorption of formaldehyde belongs to a stable chemisorption and the largest adsorption energy of formaldehyde is −2.27 eV, which is a combined action of electron transfer and hybridization effect. Formaldehyde will be preferentially adsorbed on single atom adsorbent in side-on model. The effect of N doping and desorption temperature were studied through searching for linear relationship and Gibbs free energy calculation, respectively. Doping N atoms into graphene plane can significantly improve the adsorption strength of formaldehyde through modulating the charge of metal atoms. The charge of metal atoms can be an efficient descriptor for adsorption energy of formaldehyde. CH 2 O plays a dominant role in competitive adsorption between O 2 , N 2 and CH 2 O. We expect that this theoretical study can lay a foundation for the experimental investigations. • Doping N atoms can significantly improve adsorption strength of formaldehyde. • Charge of metal atoms can be an efficient descriptor for adsorption energy. • Adsorption energy of formaldehyde on Fe/SV-N3 is −2.27 eV. • Adsorption depends on co-contribution of electron transfer and hybridization effect. • Fe/SV-N3 can be a potential and efficient adsorbent. [ABSTRACT FROM AUTHOR]

Airborne transmission is a well-established mode of dissemination for infectious diseases, particularly in closed environments. However, previous research has often overlooked the potential impact of background particle concentration on bioaerosol characteristics. We compared the spatial and temporal distributions of bioaerosols under two levels of background particle concentration: heavily polluted (150–250 μg/m3) and excellent (0–35 μg/m3) in a typical ward. Serratia marcescens bioaerosol was adopted as a bioaerosol tracer, and the bioaerosol concentrations were quantified using six-stage Andersen cascade impactors. The results showed a significant reduction (over at least 62.9%) in bioaerosol concentration under heavily polluted levels compared to excellent levels at all sampling points. The temporal analysis also revealed that the decay rate of bioaerosols was higher (at least 0.654 min-1) under heavily polluted levels compared to excellent levels. These findings suggest that background particles can facilitate bioaerosol removal, contradicting the assumption made in previous research that background particle has no effect on bioaerosol characteristics. Furthermore, we observed differences in the size distribution of bioaerosols between the two levels of background particle concentration. The average bioaerosols size under heavily polluted levels was found to be higher than that under excellent levels, and the average particle size under heavily polluted levels gradually increased with time. In conclusion, these results highlight the importance of considering background particle concentration in future research on bioaerosol characteristics. [Display omitted] • The bioaerosol distribution under different PM 2.5 concentrations is demonstrated. • The presence of background particles reduces the bioaerosol contents in the air. • Background particles can facilitate bioaerosol removal. • The higher concentration of background particles increases the size of bioaerosols. [ABSTRACT FROM AUTHOR]

• Effect of passive heating renovation on energy poverty alleviation was verified. • Coal consumption and thermal comfort were measured and compared respectively. • Air tightness, thermal defect and indoor air quality were measured and evaluated. • Potential of the passive heating renovation was explored and further optimized. • Affiliated issues for alleviating energy poverty in policy, technology, etc. were discussed. Energy poverty refers to a situation that people cannot access and use energy safely. It is a major challenge for the global energy system because of its negative impacts on household income, health, education, gender equality and environmental conditions. To solve this problem, many countries advocate the development and promotion of passive solar technology, but the effectiveness of them for energy poverty mitigation has not been evidenced. Therefore, based on empirical studies in the rural areas of Qinghai-Tibet Plateau, this paper aims at investigating the effectiveness of passive solar heating renovation to alleviate energy poverty in rural plateau areas. Specifically, this paper compared and analyzed the coal consumption and indoor air quality during the heating period before and after the renovation of a single-storey building. Further, based on the IES-VE numerical simulation, this paper analyzed the impact of building envelope structure performance on indoor air temperature. The results show that after building renovation, the coal consumption during the heating period could be reduced by 97 kg/week, while the indoor average temperature of two bedrooms were increased by 4.8 °C and 1.7 °C respectively. Setting up the coal stove as an auxiliary heating device, can alleviate the defects of insufficient heating of passive solar energy technology, and indoor temperature could be further improved. However, indoor air quality was lowered because of the high PM 2.5 concentration. In contrast, improving envelope performance could further improve the average temperature of two bedrooms and the sunspace to 16.7 °C, 15.9 °C and 15.6 °C, meeting the requirements of indoor space heating. In general, passive solar heating could achieve satisfactory results, but to alleviate energy poverty effectively in rural plateau areas, further attention should be paid to other technical, economic, social and policy issues. [ABSTRACT FROM AUTHOR]

Abstract To relieve soil thermal accumulation and performance degradation over a long-time operation for ground source heat pump (GSHP) system in cooling-dominated area, a hybrid GSHP system with cooling tower (HGSHP) was proposed. The purpose of this paper is to study the performance and feasibility of HGSHP in Shanghai. Firstly, the simulation model of GSHP system for an office building was established by TRNSYS 17.0 and the reliability of simulation was validated by the measurement data. Then, one-year and ten-year variation of performance parameters of GSHP and HGSHP systems were calculated respectively and explored in depth. These results shown that, compared with GSHP system, the annual average electricity consumption of HGSHP system decreased by 6.40% and coefficient of performance (COP) increased by 7.12% during the first year of operation. Additionally, the outlet temperature of buried pipes was below 32 °C for HGSHP system during ten-year operation, while in GSHP system, the over-standard rate of outlet temperature of buried pipes could reach approximately 80% and soil temperature increased by 10.9 °C. These findings indicated that HGSHP system could provide a feasible solution for cooling and heating in hot summer and cold winter zones. Highlights • GSHP system for case building was evaluated by field measurement and simulation. • A cooling tower-assisted hybrid ground source heat pump system was proposed. • Performance parameters for these two systems for one and ten years were compared. • Feasibility and performance of this novel HGSHP system was confirmed. [ABSTRACT FROM AUTHOR]

The protein tyrosine phosphatase PTP1B, which is encoded by PTPN1, is a ubiquitously expressed nonreceptor protein tyrosine phosphatase. PTP1B has long been known to negatively regulate insulin and leptin receptor signalling. Recently, it was reported to be aberrantly expressed in cancer cells and to function as an important oncogene. In this study, we found that PTP1B protein levels are dramatically increased in breast cancer (BC) tissues and that PTP1B promotes the proliferation, and suppresses the apoptosis, of both HER2‐positive and triple‐negative BC cell lines. Bioinformatics analysis identified that the miRNA, miR‐193a‐3p, might potentially target PTP1B. We demonstrate that miR‐193a‐3p regulates PTP1B in BC cells and that it regulates the proliferation and apoptosis of BC cells by targeting PTP1B, both in vitro and in vivo. In conclusion, this study confirms that PTP1B acts as an oncogene in BC and demonstrates that miR‐193a‐3p can serve as a tumour suppressor gene in BC by targeting PTP1B. Dysregulation of miR‐193a‐3p leads to PTP1B overexpression via a post‐transcriptional mechanism in HER2‐positive and triple‐negative breast cancer (BC) cells. The miR‐193a‐3p/PTP1B regulatory axis promotes cell proliferation, suppresses apoptosis and ultimately accelerates BC progression. [ABSTRACT FROM AUTHOR]

Abstract The energy consumption in buildings accounts for a significant proportion of total energy and carbon emissions over the world. To reduce the building energy consumption and achieve sustainable development of buildings, nearly zero energy buildings (NZEBs) have attracted widespread attention as a future building energy target. This paper reviews energy-efficient measures (EEMs) and renewable energy technologies (RETs) in NZEBs and discusses the application and suitability of the key technologies, i.e. minimizing the energy demand in NZEBs by EEMs and adopting RETs to meet the remaining energy needs. EEMs contain efficient thermal insulation system, high-performance window system, good airtightness and fresh air heat recovery system. RETs are composed of solar photovoltaic/thermal (PV/T) system, air source heat pump system (ASHP), ground source heat pump system (GSHP), and wind power. In addition, this paper emphasizes further research works, which involve life cycle energy analysis (LCEA), meteorological parameters change, intelligent building operation management (IBOM) system, energy storage system and social policy issues. This paper will provide some references for the further development of NZEBs in different climatic regions in China. Highlights • This paper systematically reviews application of EEMs and RETs in NZEBs in China. • Feasibility and suitability of EEMs and RETs are evaluated from different aspects. • Further research work and development direction of NZEBs are pointed out. [ABSTRACT FROM AUTHOR]

Highlights • Solar-air energy heating system coupled with floor radiation system was presented. • We quantitatively evaluated the contribution of the solar house to energy poverty alleviation. • Energy consumption and indoor temperature were measured and compared. • We analysed the performance of the hybrid heating system in the solar house. Abstract Energy poverty is prominent in rural Qinghai-Tibet region, China. In sacrifice of thermal comfort and health, residents adaptively choose the biomass fuels and cheap coal for heating and cooking, as an approach to energy expenditure reduction. Considering renewable energy utilization is effective to replace the utilization of conventional fuel, this paper aims to examine the potential of using solar house for energy poverty alleviation. Based on a novel hybrid heating system, we renovated a rural building into a solar house in Wangtun village, Qinghai-Tibet region. The energy consumption and indoor air temperature of the building before and after reconstruction were field measured and comparatively analysed. Results indicate that the energy consumed by solar house with the hybrid heating system was 153.3 kWh/day lower than that by the old building. The average air temperature of the living room and two bedrooms in the solar house reached 12.8°C, 11.0°C and 10.2°C, about 8.78°C, 7.61°C and 6.82°C higher than temperatures of the rooms in the old building. Overall, the solar house has considerably improved indoor environments and provided people with better thermal comfort. It is concluded that solar house can be an effective approach to mitigate domestic energy poverty of the rural Qinghai-Tibet region. The findings may also instruct other rural regions in either China or other developing countries to address the issue of energy poverty. [ABSTRACT FROM AUTHOR]

Highlights • The primary microbial distribution parts for HAVC systems were summarized. • The corresponding predominant mold and bacteria species were identified. • The mold growth partition diagram based on the limit growth curve was proposed. • Factors affecting growth and deposition of microbial particles were determined. • Effective and combined microbial control strategies for HVAC were presented. Abstract With the outbreaks of SARS, MERS, H7N9 and many other epidemic diseases, microbial contamination has become a significant focus in both HVAC and epidemiology fields. HVAC systems are the "respiratory system" of modern buildings, regulating indoor temperature, humidity, airflow and cleanness. However, they will be the sources of microbial contamination worsening indoor environment and threatening occupants' health if they are improperly designed or operated. To prevent and reduce microbial contamination, it is essential to have an overall understanding of microbial characteristics in HVAC systems. Therefore, this paper provides a comprehensive review of the distribution characteristics, growth and transmission modes of microorganisms in HVAC systems, as well as the microbial control strategies. In specific, this study reviews the HVAC components where microorganisms primarily grow and the corresponding microbial species. Afterwards, this study analyses factors that can decide the microbial growth and reproduction, and then presents the mould growth partition diagram that identifies the suitable conditions for microbial growth. Moreover, main factors that can affect the transmission of microbial aerosol in HVAC systems are also summarised. Based on these, effective strategies for constraining microbial contamination are put forward. Besides, this study further clarifies current situations and future directions of the studies on the microbial contamination in HVAC systems. Overall, this study can inform HVAC engineers and epidemiologists with a basic understanding of how to reduce indoor microbial contamination and preserve better indoor environments. [ABSTRACT FROM AUTHOR]

Objects The aim of this trial was to evaluate the effect of short-term high-dose atorvastatin therapy on levels of high-sensitivity C-reactive protein (hs-CRP), malonaldehyde (MDA), endothelin-1(ET-1), matrix metalloproteinases (MMPs), and left ventricular (LV) remodeling in patients with first time attack of acute anterior myocardial infarction (AAMI). Methods A hundred and three patients with first time attack of AAMI who underwent successful primary percutaneous coronary intervention were randomized to receive atorvastatin 40 mg once daily for 1 week followed by 20 mg once daily (intensive treatment group, IT group, n =49), or atorvastatin 20 mg once daily (standard treatment group, ST group, n =54). Plasma levels of hs-CRP, MDA, ET-1, MMP-2 and MMP-9 were measured on admission, at 1 week, 2 weeks and 6 months follow up and compared between the IT group and ST group. Echocardiography was performed on admission, at 2 week, and 1 year follow up. The left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV) and left ventricular ejection fraction (LVEF) were measured at each echocardiographic examination and compared between the IT group and ST group. Results Plasma levels of hs-CRP ( F =7.718, P =0.009), ET-1 ( F =7.882, P =0.006), MMP-9 ( F =4.834, P =0.028) and pro-BNP ( F =4.603, P =0.032) were significantly lower at 1 week after initial onset of AAMI in the IT group compared with the ST group. The changes of LVEDV, LVESV, and LVEF at the 1 year follow-up from the admission did not differ between the IT group and the ST group ( t =0.722, P =0.444; t =1.228, P =0.221; t =1.354, P =0.187, repectively). Conclusions Short-term high-dose atorvastatin treatment for AAMI was associated with lower hs-CRP, ET-1 and MMP-9 levels compared to the standard dose treatment. However, this beneficial effect is not likely to related to the left ventricular remodeling. [ABSTRACT FROM AUTHOR]

Solar heating should be recommended strongly for domestic buildings in the Qinghai–Tibetan plateau due to the area's high intensity radiation. In this paper, a novel hybrid solar heating system is presented, that includes a solar kang system, a Trombe wall and a direct gain window. The effects of five combined solar heating operation modes on the indoor hourly temperature for one case domestic building located in the Qinghai–Tibetan plateau were investigated by field measurement and numerical simulation. The optimal operation mode for improving the indoor thermal environment was determined. Furthermore, the effectiveness of each operational mode on the east room was quantitatively evaluated and ranked. The results show that the numerical simulation and field experimental results were well agreed, although there were some differences in specific values. In addition, the results it indicated that a solar kang running all days and Trombe wall running daytime played a significant role in improving the indoor thermal temperature. These relevant findings could provide a reference for solar heating system design and indoor thermal comfort improvement for rural domestic buildings in the Qinghai–Tibetan plateau. [ABSTRACT FROM AUTHOR]

A finite element model of silicon nitride grinding was created based on virtual abrasives with a truncated polyhedral shape, to simulate the subsurface damage depth. Due to the influence of materials on light reflection, a new method to detect the subsurface damage depth was presented based on the light intensity. A series of orthogonal experiments were accomplished by using a MGK7120 × 6/F NC surface grinder. The influence of the grinding parameters, such as the wheel speed, workpiece speed and grinding depth, were analysed for their effects on the subsurface damage depth. A prediction model of the subsurface damage depth was built by conducting a regression analysis of the experimental data. The results indicated that the average error between the model prediction and experimental testing was approximately 9%, which validated the predication accuracy and the generalization ability of the prediction model. [ABSTRACT FROM AUTHOR]

FeWO 4 nanorods were synthesized through a hydrothermal progress with the assistant of L -cysteine. The synthesized FeWO 4 nanorods were characterized by X-ray powder diffraction, Raman spectrometer, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscope and X-ray photoelectron spectroscopy. The optical property, photocatalytic activity and magnetic property of the synthesized FeWO 4 nanorods were investigated. The photodecomposition of Methyl orange for FeWO 4 nanorods depends on the wavelength of the irradiating light. Under ultraviolet-visible light irradiation, FeWO 4 nanorods show higher photocatalytic activity for the decomposition of Methyl orange than that of ultraviolet light irradiation. A possible mechanism of FeWO 4 on the decomposition of Methyl orange was proposed. The value of Néel temperature is lower than that of bulk FeWO 4 , which is associated with the size effects and the shape of the synthesized FeWO 4 nanorods. [ABSTRACT FROM AUTHOR]

Predicting the performance of solar water heater (SWH) is challenging due to the complexity of the system. Fortunately, knowledge-based machine learning can provide a fast and precise prediction method for SWH performance. With the predictive power of machine learning models, we can further solve a more challenging question: how to cost-effectively design a high-performance SWH? Here, we summarize our recent studies and propose a general framework of SWH design using a machine learning-based high-throughput screening (HTS) method. Design of water-in-glass evacuated tube solar water heater (WGET-SWH) is selected as a case study to show the potential application of machine learning-based HTS to the design and optimization of solar energy systems. [ABSTRACT FROM AUTHOR]

The infectious pathogen-laden aerosols generated by infected patients have a significant impact on the safety of surgical staff in highly clean negative-pressure operating rooms. Understanding the transmission characteristics of infectious pathogen-laden aerosols is therefore essential. Therefore, in this study, we conducted experiments in a full-size negative-pressure operating room, and the Phi-X174 phage was used as a bioaerosol release source to investigate the migration and deposition of bioaerosols. The high-concentration spatial regions and high-concentration deposition surfaces of the bioaerosols in the operating room were determined. The results showed that there was a high concentration of bioaerosols in the vortex region below the medical lamp for extended periods of time. Three surgical staff members close to the patient's surgical site had high bioaerosol concentrations at their facial sampling points, with the highest concentration reaching 16,553 PFU/m³. At the end of bioaerosol generation, 99.9% of the bioaerosols were discharged within 10 mins. The bioaerosol deposition rates per unit area were high at 1.48%/m2, 0.46%/m2 and 1.79%/m2 for the central control panel, storage cabinet, and door surface, respectively. This research can be used as a scientific reference for controlling bioaerosols and determining key disinfection parts in a negative-pressure operating room. [Display omitted] • The spatial-temporal variation law of bioaerosol concentration were determined. • The bioaerosol was completely discharged within 10 mins after surgery. • More than 19% of the bioaerosols were deposited on the indoor surface. • Bioaerosols have a high deposition potential on the surfaces of equipment. [ABSTRACT FROM AUTHOR]

Droplets or aerosols loaded with SARS-CoV-2 can be released during breathing, coughing, or sneezing from COVID-19-infected persons. To investigate whether the most commonly applied air-cleaning device in dental clinics, the oral spray suction machine (OSSM), can provide protection to healthcare providers working in clinics against exposure to bioaerosols during dental treatment. In this study, we measured and characterized the temporal and spatial variations in bioaerosol concentration and deposition with and without the use of the OSSM using an experimental design in a dental clinic setting. Serratia marcescens (a bacterium) and ΦX174 phage (a virus) were used as tracers. The air sampling points were sampled using an Anderson six-stage sampler, and the surface-deposition sampling points were sampled using the natural sedimentation method. The Computational Fluid Dynamics method was adopted to simulate and visualize the effect of the OSSM on the concentration spatial distribution. During dental treatment, the peak exposure concentration increased by up to 2–3 orders of magnitude (PFU/m3) for healthcare workers. Meanwhile, OSSM could lower the mean bioaerosol exposure concentration from 58.84 PFU/m3 to 4.10 PFU/m3 for a healthcare worker, thereby inhibiting droplet and airborne transmission. In terms of deposition, OSSM significantly reduced the bioaerosol surface concentration from 28.1 PFU/m3 to 2.5 PFU/m3 for a surface, effectively preventing fomite transmission. The use of OSSM showed the potential to restraint the spread of bioaerosols in clinical settings. Our study demonstrates that OSSM use in dental clinics can reduce the exposure concentrations of bioaerosols for healthcare workers during dental treatment and is beneficial for minimizing the risk of infectious diseases such as COVID-19. [ABSTRACT FROM AUTHOR]

Most buildings in the cold climate zone have unbalanced loads, mainly dominated by heating loads. The cold buildup within the soil would definitely reduce the soil temperature, which could consequently disturb the soil temperature balance, and furthermore, deteriorate the performance of ground source heat pump. A hybrid ground-source heat pump (HGSHP) with auxiliary heat source could be proposed to solve this problem. The paper aimed at investigating the feasibility and performance of HGSHP in Shenyang located in the cold area. Firstly, hourly dynamic loads of one office building were calculated. Then, three systems, including one HGSHP system with boiler as auxiliary heat source, ground source heat pump system (GSHP), and a traditional electric water chiller + boiler system (WB) were designed and simulated for this office building by TRNSYS. Several performance parameters for these three systems were obtained. These parameters included the hourly outlet/inlet temperature of buried pipes, hourly soil temperature, energy consumption distribution and the coefficient of performance (COP). Simulation results indicated that HGSHP system with boiler as auxiliary heat source could effectively solve cold accumulation problem and reduce traditional energy consumption. These results could provide some reference on HGSHP system utilization in the cold climate zones of China. [ABSTRACT FROM AUTHOR]

How to design water-in-glass evacuated tube solar water heater (WGET-SWH) with high heat collection rates has long been a question. Here, we propose a high-throughput screening (HTS) method based on machine learning to design and screen 3.538125 × 10 8 possible combinations of extrinsic properties of WGET-SWH, to discover promising WGET-SWHs by comparing their predicted heat collection rates. Two new-designed WGET-SWHs were installed experimentally and showed higher heat collection rates (11.32 and 11.44 MJ/m 2 , respectively) than all the 915 measured samples in our previous database. This study shows that we can use the HTS method to modify the design of WGET-SWH with just few knowledge about the highly complicated correlations between the extrinsic properties and heat collection rates of solar water heaters. [ABSTRACT FROM AUTHOR]

Renewable energy systems combining hybrid energy storage (HES-RESs) and new energy vehicles are beneficial for realizing net-zero carbon emissions of the building and transport sectors. However, the configuration and operation of HES-RESs lack mature optimization methods, and the competition between systems that consider electric vehicles and hydrogen vehicles is unclear. Therefore, a RES that combines electricity storage, hydrogen storage, and heat storage is proposed. The nonlinear model of the HES-RES is established. A two-layer collaborative optimization model of system design and operation is constructed. The economy, environment, and independence of the HES-RES are improved. Then, the system is applied to a diversified nearly zero-energy community, and the optimization results considering electric vehicles and hydrogen vehicles are compared. The variation in performance, configuration, and operation of the HES-RES are quantitatively analysed with different proportions of hydrogen vehicles. The results show that the annual carbon emissions and costs of the HES-RES considering electric vehicles are reduced by 39.5% and 25.6%, respectively, and the grid interaction is increased by 10.0%, compared to the system only considering hydrogen vehicles. The HES-RES and the optimization results have a positive guiding role for the carbon emission reduction and integration development of the building and transport sectors. • A system combining electricity storage, hydrogen storage, heat storage is proposed. • Two-layer collaborative optimization model of system design and operation is set up. • The systems considering electric vehicles and hydrogen vehicles are compared. • The stability of the two-layer collaborative optimization method is verified. [ABSTRACT FROM AUTHOR]

[Display omitted] • A distributed energy system combining lithium battery and power-to-heat/cold was proposed. • The upper layer optimized the device configuration and underlayer storage operation parameter. • The objective value and decision variable volatility were under 5% and 30%, respectively. • Researched the comprehensive performance of the system in a nearly-zero energy community. With the rapid development of nearly zero-energy buildings, the establishment of a nearly zero-energy community composed of concentrated and contiguous nearly zero-energy buildings constitutes the future architectural trend. However, configuration and optimization research of distributed energy systems combining multiple energy storages (DES-MESs) for the nearly zero-energy community is not sufficiently mature. Therefore, this paper initially proposed a DES-MES combining power-to-heat, power-to-cold and lithium batteries. Subsequently, a two-layer co-optimization method was proposed considering the equipment configuration in the upper layer and energy storage operating parameters in the under-layer. Based on the nearly zero-energy community, the influence of the initial parameters on the DES-MES optimization results was studied. Then, comparative research of different co-optimization methods was conducted. Finally, analysed the interactive electricity quantity, annual cost, carbon dioxide emissions, etc., of the DES-MES under the nearly zero-energy community scenario. The results indicated that the stability of the performance indicators (volatility under 5.0%) and decision variables (volatility under 30.0%) of the system were much higher than those determined with multi-parameter or multi-stage co-optimization methods. Compared to the separated production system, the primary energy consumption and carbon dioxide emissions of the DES-MES were reduced by 4.7 × 106 kWh (72.3%) and 1.6 × 106 kg (79.0%), respectively. The two-layer co-optimization method could effectively solve the problem of balancing the accuracy of the optimization results and calculation time. This paper provides a solution for the study of the system structure, operation optimization, and performance indicators of the DES-MES under the nearly zero-energy community scenario. [ABSTRACT FROM AUTHOR]

• Experimental-numerical study on the transmission of bacteria-carrying particles. • Clean air is the result of the interaction between thermal plume and ventilation. • The performance of four ventilation systems was compared. • Temperature-controlled airflow ventilation is effective ventilation. During surgery, the release of bacterial-carrying particles (BCPs) by surgeons is one of the major pollution sources in operating rooms (ORs), which may cause surgical site infection (SSIs) or health problems. The human thermal plume emitted by the human body may affect the airflow in the surgical micro-environment, leading to the further spread of BCPs. Therefore, this paper aimed to evaluate and compare the diffusion of human thermal plume and BCPs under the design conditions of four ventilation systems (vertical laminar airflow ventilation (VLAF1), horizontal laminar airflow ventilation (HLAF), vertical laminar airflow ventilation (VLAF2), and temperature-controlled airflow ventilation (TAF)). The experiments of airspeed measurements and biological particle emission were carried out in a standard vertical laminar ventilation operating room. Computational fluid dynamics (CFD) was used to extend the investigation of the different ventilation systems. In summary, both the VLAF and TAF systems were able to interact effectively with the human thermal plume, and the TAF ventilation system was superior to the other three systems in reducing BCPs levels in the air of the operating room. The TAF system was able to control the BCPs concentration in the surgical area to 20 CFU/m3. The interaction between human thermal plume and ventilation plays an important role in the clearance of BCPs in the operating room, so it is significant to systematically compare the performance of different ventilation systems. [ABSTRACT FROM AUTHOR]

Background: Heat collection rate and heat loss coefficient are crucial indicators for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, the direct determination requires complex detection devices and a series of standard experiments, wasting too much time and manpower. Findings: To address this problem, we previously used artificial neural networks and support vector machine to develop precise knowledge-based models for predicting the heat collection rates and heat loss coefficients of water-in-glass evacuated tube solar water heaters, setting the properties measured by 'portable test instruments' as the independent variables. A robust software for determination was also developed. However, in previous results, the prediction accuracy of heat loss coefficients can still be improved compared to those of heat collection rates. Also, in practical applications, even a small reduction in root mean square errors (RMSEs) can sometimes significantly improve the evaluation and business processes. Conclusions: As a further study, in this short report, we show that using a novel and fast machine learning algorithm-extreme learning machine can generate better predicted results for heat loss coefficient, which reduces the average RMSEs to 0.67 in testing. [ABSTRACT FROM AUTHOR]

NaGd(WO 4 ) 2 :Eu 3+ /Bi 3+ films were deposited on SiO 2 glass substrates by spin-coating. The as-prepared films were heat treated at different temperatures. The properties of films were characterized by TG-DSC, XRD, SEM and fluorescence spectrophotometer. The TG-DSC curve indicated that films began to crystallize at about 600 °C. The XRD patterns and SEM images of films annealed at 600 °C, 700 °C and 800 °C showed that a higher temperature benefits to the higher crystallinity and induces the lower thickness. Meanwhile, it was found that the revolution of spin coating influenced the morphology of films obviously. Under the excitation at 396 nm, NaGd(WO 4 ) 2 :Eu 3+ /Bi 3+ films showed characteristic emission bands originating from 5 D 0 → 7 F j ( j = 1, 2, 3, and 4) transitions of Eu 3+ ions. It was also found that the excitation wavelength has great effect on the emission intensity. [ABSTRACT FROM AUTHOR]

Eu 3+ ions doped LaBWO 6 phosphors were synthesized by a facile hydrothermal method. The phase, morphology and luminescence properties of the obtained samples were characterized. The XRD, Raman and IR results showed that the obtained samples have the orthorhombic phase, indicating the doped Eu 3+ will not change the phase of host. The TEM and SEM images showed that the obtained sample have the rod-like morphology. The excitation spectrum showed that Eu 3+ ions doped LaBWO 6 phosphors have excitation bands ranging from the ultraviolet region to blue region. The emission spectra showed that Eu 3+ ions doped LaBWO 6 phosphors emit dominate red light under 281, 394 and 464 nm excitations. And the decay of the red emission fitted well with the double exponential function. [ABSTRACT FROM AUTHOR]