Removal of organic micropollutants from water through advanced oxidation processes (AOPs) is hampered by the excessive input of energy and/or chemicals as well as the large amounts of residuals ...resulting from incomplete mineralization. Herein, we report a new water purification paradigm, the direct oxidative transfer process (DOTP), which enables complete, highly efficient decontamination at very low dosage of oxidants. DOTP differs fundamentally from AOPs and adsorption in its pollutant removal behavior and mechanisms. In DOTP, the nanocatalyst can interact with persulfate to activate the pollutants by lowering their reductive potential energy, which triggers a non-decomposing oxidative transfer of pollutants from the bulk solution to the nanocatalyst surface. By leveraging the activation, stabilization, and accumulation functions of the heterogeneous catalyst, the DOTP can occur spontaneously on the nanocatalyst surface to enable complete removal of pollutants. The process is found to occur for diverse pollutants, oxidants, and nanocatalysts, including various low-cost catalysts. Significantly, DOTP requires no external energy input, has low oxidant consumption, produces no residual byproducts, and performs robustly in real environmental matrices. These favorable features render DOTP an extremely promising nanotechnology platform for water purification.
An essential task of numerical weather prediction (NWP) is accurate surface wind speed prediction. However, current NWP models contain significant systematic errors due in part to indeterminate ...ground forcing (GF). This study considers an optimal virtual GF (GFo) derived by training observed and simulated data sets of 10‐m wind speeds (WS10) for summer and winter. The GFo is added to an offline surface multilayer model (SMM) to revise predictions of WS10 in China by the Weather Research and Forecasting model (WRF). This revision is a data‐based optimization under physical constraints. It reduces WS10 errors and offers wide applicability. The resulting model outperforms two purely physical forecasts (the original WRF forecast and the SMM with physical GF parameterized using urban, vegetation, and subgrid topography) and two purely data‐based revisions (i.e., multilinear regression and multilayer perceptron). Compared with the original WRF forecasting, using the GFo scheme reduces the root mean square error in WS10 across China by 25% in summer and 32% in winter. The frontal area index of GFo indicates that it includes both the effects of indeterminate GF and other possible complex physical processes associated with WS10.
Plain Language Summary
Predicting surface wind speed is crucial to operational weather forecasting. However, current forecast models include significant errors owing to uncertainties in ground forcing (GF). This study adds optimal GF to an offline surface multilayer model to revise forecasts in China by the Weather Research and Forecasting model, thereby significantly improving 10‐m wind speed forecasts.
Key Points
An offline surface multilayer model incorporating turbulence and indeterminate ground forcing is applied to revise surface wind speed forecasts
Ground forcing is optimized using 10‐m wind speed observations
Applying the optimal data‐based ground forcing can reduce errors in 10‐m wind speed forecasts in China by 25% in summer and 32% in winter
Emotions are pervasive in the tourism experience. However, most studies on tourist environmentally responsible behavior (ERB) adopt a moral or rational perspective, marginalizing the effect of ...tourists' emotional states. This study plugs this gap by linking tourists’ positive emotions with two types of ERBs, namely ethical ERB and philanthropic ERB. A conceptual model comprising positive emotions, self-efficacy, place identity, and tourist ERB is developed and empirically tested with data collected at a typical nature-based tourism destination in China. The results reveal a positive association between positive emotions and both types of tourist ERB. Notably, positive emotions have no direct effect on tourist ERB but do have indirect effects through self-efficacy and place identity, which serve as mediators that bridge positive emotions and tourist ERB. These findings enrich the literature by highlighting the role which positive emotions play in the tourist ERB model and offer valuable insights for the environmental management of tourism destinations.
The dogma that urine is sterile in healthy individuals has been overturned by recent studies applying molecular-based methods. Mounting evidences indicate that dysbiosis of the urinary microbiota is ...associated with several urological diseases. In this study, we aimed to investigate the urinary microbiome of male patients with calcium-based kidney stones and compare it with those of healthy individuals.
The diversity of the urinary microbiota in kidney stone patients was significantly lower than that of healthy controls based on the Shannon and Simpson index (P < 0.001 for both indices). The urinary microbiota structure also significantly differed between kidney stone patients and healthy controls (ANOSIM, R = 0.11, P < 0.001). Differential representation of inflammation associated bacteria (e.g., Acinetobacter) and several enriched functional pathways were identified in the urine of kidney stones patients. Meanwhile, we found the species diversity, overall composition of microbiota and predicted functional pathways were similar between bladder urine and renal pelvis urine in kidney stone patients.
A marked dysbiosis of urinary microbiota in male patients with calcium-based kidney stones was observed, which may be helpful to interpret the association between bacteria and calcium-based kidney stones.
The background error covariance matrix plays a vital role in any data assimilation system. Proper specification, which is determined by the forecast system set‐up, is often required. Previous studies ...have investigated its relevance in various global and regional numerical weather prediction (NWP) systems; however, very few have explored it in tropical NWP systems. Here, we present and evaluate the structures of the background error covariance matrix for a tropical convective‐scale NWP system. A total of 12 background error covariance matrices are modelled using differences between pairs of forecasts of different lengths but valid at the same time, based on the application of the vertical‐first and horizontal‐first transform order formulations on six permutations of the training data. Through pseudo‐single observation tests, we extract and test the sensitivity of their structures to the training data period (seasons), forecast lag and transform order. The structures typically exhibit more dependence on forecast lag and transform order; horizontal‐first transform order covariances had structures with shorter horizontal length‐scales for wind and larger wind background error standard deviations. We also note that some covariances had horizontal and vertical structures with stronger mass–wind coupling, closely resembling an equatorial Kelvin wave. To assess the performance of each of the covariances, 12 month‐long data assimilation trials in May 2018 (characterised by frequent occurrences of localised thunderstorm events) are performed. We show improved short‐range precipitation forecasts in trials using some of the covariances compared to the current operational covariance. These covariances generally have structures with weak mass–wind coupling, shorter horizontal length‐scales for wind and larger wind background error standard deviations, compared to other covariances which led to poorer forecasts. These may be desirable factors when modelling the background error covariance matrix for tropical convective‐scale data assimilation systems.
We investigate the structures and impact of the background error covariance matrix for a tropical convective‐scale numerical weather prediction system, SINGV‐DA, using pseudo‐single observation tests. Horizontal and vertical structures may closely resemble an equatorial Kelvin wave. Month‐long trial results suggest that weak mass–wind coupling, shorter horizontal length‐scales for wind, and larger wind background error standard deviations in the structures may be desirable for tropical convective‐scale data assimilation.
There is still no consensus on the mechanisms that modify precipitation over and around cities, especially for those located in the tropics where convective processes primarily drive rainfall. Here ...we contribute to the ongoing discussion about the urban‐associated precipitation by investigating the urban effect on the diurnal cycle of rainfall over Singapore. We use the urban version of the numerical weather prediction system of the Meteorological Service Singapore (hereafter called uSINGV) at a 300 m horizontal resolution to simulate the rainfall conditions over Singapore and its surroundings during the inter‐monsoon period between 2010 and 2014. Two simulations with different land surface conditions are conducted: one with urban areas (i.e. present conditions) and one without urban areas. uSINGV is shown to perform well for rainfall when compared to observations. Comparison between simulations reveals that the urban area is responsible for the formation of a rainfall “hot spot” over Singapore and Johor Bahru, located at the southern tip of the Malay Peninsula, and the urban effect is accountable for 20–30% of total rainfall during late afternoons and evenings, highlighting a strong urban effect on localized rainfall over a tropical city. Enhancement of convection due to the urban heat island effect, increased frictional convergence due to buildings' drag, the seaward shift of the sea‐breeze front, and the increased inflow of boundary‐layer moisture by the stronger sea breeze are suggested as most probable reasons for the increased rainfall in the urban area.
Diurnal cycle of simulated rain rate from URB and NO_URB. The values shown here are five‐November (2010–2014) averages over the rectangle shown in the inset map which includes parts of Singapore and Johor Bahru in Malaysia (referred to as SGJB in the text). The colour‐shaded areas indicate the uncertainty ranges, which are derived using a bootstrapping approach and defined as a range between 25 and 75% quantiles of the bootstrap means
Immobilization of planar CoII‐2,3‐naphthalocyanine (NapCo) complexes onto doped graphene resulted in a heterogeneous molecular Co electrocatalyst that was active and selective to reduce CO2 into CO ...in aqueous solution. A systematic study revealed that graphitic sulfoxide and carboxyl dopants of graphene were the efficient binding sites for the immobilization of NapCo through axial coordination and resulted in active Co sites for CO2 reduction. Compared to carboxyl dopants, the sulfoxide dopants further improved the electron communication between NapCo and graphene, which led to the increase of turnover frequency of the Co sites by about 3 times for CO production with a Faradic efficiency up to 97 %. Pristine NapCo in the absence of a graphene support did not display efficient electron communication with the electrode and thus failed to serve as the electrochemical active site for CO2 reduction under the identical conditions.
No plain, no gain: Immobilization of planar CoII‐2,3‐naphthalocyanine (NapCo) complexes onto sulfoxide or carboxyl doped graphene resulted in a heterogeneous molecular Co electrocatalyst that was active and selective to reduce CO2 into CO in aqueous solution.
The non-contact detection of human vital signs (i.e., respiration rate (RR) and heartbeat rate (HR)) using a continuous-wave (CW) Doppler radar sensor has great potential for intensive care ...monitoring, home healthcare, etc. However, large-scale and fast random body movement (RBM) has been a bottleneck for vital sign detection using a single CW Doppler radar. To break this dilemma, this study proposed a scheme combining adaptive noise cancellation (ANC) with polynomial fitting, which could retrieve the weak components of both respiration and heartbeat signals that were submerged under serious RBM interference. In addition, the new-type discrete cosine transform (N-DCT) was introduced to improve the detection accuracy. This scheme was first verified using a numerical simulation. Then, experiments utilizing a 10-GHz Doppler radar sensor that was built from general-purpose radio frequency (RF) and communication instruments were also carried out. No extra RF/microwave components and modules were needed, and neither was a printed circuit board nor an integrated-chip design required. The experimental results showed that both the RR and HR could still be extracted during large-scale and fast body movements using only a single Doppler radar sensor because the RBM noises could be greatly eliminated by utilizing the proposed ANC algorithm.
Stability is an important constraint in power system operation and the transient stability constrained optimal power flow (OPF) has always received considerable attention in recent years. In this ...paper, the defects of the existing models and algorithms around this topic are firstly analyzed, on the basis of which, a multi-objective optimization method is proposed. The basic idea of the proposed method is to model transient stability as an objective function rather than an inequality constraint and consider classic transient stability constrained OPF (TSCOPF) as a tradeoff procedure using Pareto ideology. Second, a master-slave parallel elitist non-dominated sorting genetic algorithm II is used to solve the proposed multi-objective optimization problem, the parallel algorithm shows an excellent acceleration effect and provides a set of Pareto optimal solutions for decision makers to select. An innovative weight assigning technique based on fuzzy membership variance is also introduced for a more scientific and objective optimal solution decision. Case study results demonstrate the proposed multi-objective method has many advantages, compared with traditional TSCOPF methods.
•Novel pin fin-interconnected reentrant microchannels (PFIRM) were developed.•Operational characteristics of PFIRM in flow boiling were systematically explored using two coolants.•Effects of heat ...flux, mass flux, inlet subcooling and coolants on flow boiling performance of PFIRM were assessed.•PFIRM facilitated to provide ideal spaces for the bubble nucleation and movement and suppress bubble confinement effect.
Pin fin-interconnected reentrant microchannels (PFIRM) are proposed and developed for microchannel heat sinks cooling systems to combine both merits of reentrant cavities and micro pin fins in heat transfer enhancement. They feature two directions of reentrant microchannels with a intersection angle of 30° in the downside, and staggered arrays of micro diamond pin fins on the upper side. Micro-milling process is utilized to process the interconnected reentrant microchannels, which simultaneously induces the formation of micro diamond pin fins. Flow boiling experiments are conducted using two coolants (deionized water and ethanol) at inlet subcoolings of 40 °C and 10 °C, mass fluxes of 125–300 kg/(m2 s). Flow boiling heat transfer, pressure drop and two-phase flow instabilities of the PFIRM are systematically assessed. It is found that the PFIRM showed a 39–284% enhancement in two-phase heat transfer in water tests, and a 29–220% in ethanol tests compared to the parallel reentrant microchannels. Decrease of bubble confinement effect by the interconnected microchannels and ideal spaces for the bubble nucleation and movement supplied by the reentrant chambers contributed to the above boiling heat transfer enhancement of PFIRM. The PFIRM heat sink operated more efficiently using the coolant of water than ethanol.
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