Considering the interrelatedness of river and bay ecosystems, river and bay water quality management is shifting to integrated management across coastlines. Here, an integrated management indicator ...for the coordinated and efficient nitrogen abatement of the Bohai Sea and its basin was proposed. The terrigenous total nitrogen (TN) allocated load was optimized under the dual water quality constraints for both river and bay using a simulation–optimization method. The contributing jurisdictions were identified by their TN overload rates, and their responsibility apportionment rate for specific nitrogen-polluted segment was quantified. Integrated TN reduction scheme resulted in a 29 % greater reduction in bay and river nitrogen pollution than the equal proportion reduction approach. In 18 % of the watersheds in the Bohai basin, the water quality standards of the river were more restrictive than the standards of the bay. Integrated management scheme has higher coordination of river and sea management objectives.
Display omitted
•Allocated load is for water quality objectives of both Bohai Sea and its basin.•Contributing jurisdictions for each nitrogen-polluted segment was indentified.•Integrated nitrogen management scheme for bay and its basin is high-efficient.•Simulation-optimization method is suitable for multi-objective management.
Using phosphogypsum (PG) as a raw material to prepare calcium sulphoaluminate cement (CAS) is an effective way of treating phosphogypsum. In order to meet the different application requirements of ...CSA cement and promote the application of CAS cement, it is necessary to add mineral admixtures to adjust the performance of cement. This paper incorporated two minerals, gypsum dihydrate (C$H2) and calcium hydroxide (CH), into cement clinker prepared from phosphogypsum. The compressive strength and hydration process of the mixtures with different blending levels were investigated around the C4A3$-C$H2 system (SC) and the C4A3$-C$H2-CH system (SCC). The optimum dosing level was determined on the basis of the strength and hydration properties. In the SC system, adding C$H2 promoted the hydration of C4A3$. The compressive strength of the cement was highest at a C$H2/C4A3$ molar ratio of 1.5, with a 7-day compressive strength of 56.5 MPa. AFt was mostly needle-rod and columnar and was tightly cemented to the gel phase, improving the denseness of the matrix. When the molar ratio was 2, the strength of the cement was inverted, and the shape of the AFt changed from needle and rod to columnar, the size of the grains increased, and it could not be filled with the AH3 phase in an excellent staggered manner. At the same time, C$H2 was not fully reacted, increasing matrix porosity and inversion of strength. In the SCC system, adding CH reduced the cement’s compressive strength, and the compressive strength reduction increased with the increase in admixture. According to the experimental results, CH inhibited the formation of AFt, resulting in the appearance of new hydration products, AFm. As the amount of CH increased, the amount of hydration products, AFm, increased, while the amount of AFt and AH3 decreased. However, adding CH raised the paste’s pH and later facilitated the development of strength. The optimum admixture of CH/C4A3$ was 0.5 mol.
Effective thermal management of SOFCs is necessary for their long life and highly efficient operation, while the conventional method through excess air cooling is limited due to the inherently low ...thermal conductivity and capacity of air. In this study, a novel temperature control strategy is proposed by using liquid metal as a new kind of coolant that can work in both the stable operation stage and start-stop stage of an SOFC stack. A three-dimensional model is developed considering chemical/electrochemical reactions, mass, momentum and heat transfer processes to assess the effect of liquid metal cooling. The simulation results show that liquid metal has an excellent ability to improve the temperature uniformity and electric performance of the cell unit. The temperature difference of the cell unit cooled by air cooling is 60 K, which can be decreased to 15 K with liquid tin cooling. Furthermore, inlet air has little effect on the performance of the cell unit when liquid metal is chosen as coolant. The pumping powers of the air and liquid metal are compared at different excess air ratios and inlet velocities of liquid metal. The total pumping power consumption could be dramatically decreased when liquid metal is utilized as the coolant. Furthermore, the variations in the conductivity, heat capacity and convective resistance at different liquid metal inlet velocities are discussed.
•A 3D model is developed for a planar SOFC unit with a liquid metal cooling plate.•Highly efficient temperature control can be achieved using liquid metal coolant with very low power consumption.•The excess air ratios can be reduced resulting in the dramatical decrease in the pumping power.
Abstract The theoretical results indicate that iced bundled conductors experience spatial galloping due to wind-induced vibration, involving in-plane, out-of-plane, and torsional movements. To better ...understand the dynamic response of this behavior from an experimental perspective, an innovative experimental method has been proposed. The method can simultaneously measure the in-plane, out-of-plane, and torsional vibration signals of iced bundled conductors’ galloping. A testing system was established, and the method is applied in the galloping experiment of continuous iced bundled conductors, validating some theoretical results. This paper describes the construction of a wide-aperture, low-speed wind tunnel suitable for testing the galloping of continuous iced bundled conductors. A ‘cut-bury-glue’ method was proposed to create a model of continuous iced bundled conductors effectively, along with a method for connecting subconductors to improve experimental precision. The tests utilized laser displacement sensors and wireless posture sensors, considering the installation and data collection characteristics of the sensors. Through signal conversion, error correction, and other technical methods, simultaneous measurement of in-plane, out-of-plane, and torsional vibration signals was achieved. The spatial galloping behavior, changing with wind speed, exhibits limited-amplitude and synchronous characteristics. The participation of different modes shows elliptical orbital motion in single-mode galloping and ‘8’ shaped orbital motion in coupled-mode galloping. These results are consistent with previous theoretical research, offering a new approach to studying iced bundled conductors’ galloping.
Automatic identification system (AIS) is a vessel-based system for the automatic broadcast and reception of vessel information, and it also supports data for trajectory prediction. Since the vessel’s ...sailing route is flexible and changeable and the AIS broadcast is unconfirmed, the trajectory varies greatly and the original AIS data contains some noisy trajectory, which leads to low prediction accuracy and stability. Therefore, to solve the above problem, this paper proposes a trajectory prediction method based on bidirectional gate recurrent unit (BiGRU) and trajectory direction vector (TDV) with attention mechanism. This paper firstly proposes a TDV to associate latitude and longitude with the course and speed. Then the paper proposes an attention mechanism to self-adaptively update weight to the TDV in different stages to eliminate unreasonable predicted trajectory points. Finally, this paper combines the TDV attention mechanism and the BiGRU network to train a vessel trajectory prediction model.
Display omitted
•A vessel trajectory prediction method based on BiGRU and TDV attention is proposed•The TDV attention self-adoptively tunes feature weights in different navigation•A BiGRU with attention mechanism is constructed to train a trajectory prediction model•A trajectory prediction prototype is implemented to predict vessel trajectory
Computer science; Artificial intelligence; Machine learning
Catheter-based renal denervation (RDN) has been introduced to treat resistant hypertension. Although the technology of RDN has been largely improved, denervation of tortuous renal arteries remains ...challenging.
This is a case report of a 49-year-old man with drug resistant hypertension. The patient was selected for RDN after ruling out possible causes of secondary hypertension. Computed tomography angiography showed a highly tortuous left renal artery. An Iberis multielectrode ablation catheter failed to reach the target vessel with a regular guiding catheter. A 5-French extension catheter was introduced into the proximal segment of the main left renal artery to provide extra support force, which enabled successful ablation of the highly tortuous left renal artery. His ambulatory blood pressure was significantly decreased at 1 month follow-up.
It is feasible and effective to use a guide extension catheter for denervation of highly tortuous renal arteries. The present study provides a useful method to ablate tortuous and angled renal arteries and branches.
Weakly Aggregative Modal Logic (
WAML
) is a collection of
disguised
polyadic modal logics with
n
-ary modalities whose arguments are all the same.
WAML
has interesting applications on epistemic ...logic, deontic logic, and the logic of belief. In this paper, we study some basic model theoretical aspects of
WAML
. Specifically, we first give a van Benthem–Rosen characterization theorem of
WAML
based on an intuitive notion of bisimulation. Then, in contrast to many well known normal or non-normal modal logics, we show that each basic
WAML
system
K
n
lacks Craig interpolation. Finally, by model theoretical techniques, we show that an extension of
K
2
does have Craig interpolation, as an example of amending the interpolation problem of
WAML
.
Primary dysmenorrhea (PDM) is cyclic menstrual pain in the absence of pelvic anomalies, and it is thought to be a sex‐hormone related disorder. Existing study has focused on the effects of menstrual ...cramps on brain function and structure, ignoring the psychological changes associated with menstrual pain. Here we examined whether pain empathy in PDM differs from healthy controls (HC) using task‐based functional magnetic resonance imaging (fMRI). Fifty‐seven PDM women and 53 matched HC were recruited, and data were collected at the luteal and menstruation phases, respectively. During fMRI scans, participants viewed pictures displaying exposure to painful situations and pictures without any pain cues and assessed the level of pain experienced by the person in the picture. Regarding the main effect of the pain pictures, our results showed that compared to viewing neutral pictures, viewing pain pictures caused significantly higher activation in the anterior insula (AI), anterior cingulate cortex, and the left inferior parietal lobule; and only the right AI exhibited a significant interaction effect (group × picture). Post‐hoc analyses confirmed that, relative to neutral pictures, the right AI failed to be activated in PDM women viewing painsss pictures. Additionally, there was no significant interaction effect between the luteal and menstruation phases. It suggests that intermittent pain can lead to abnormal empathy in PDM women, which does not vary with the pain or pain‐free phase. Our study may deepen the understanding of the relationship between recurrent spontaneous pain and empathy in a clinical disorder characterized by cyclic episodes of pain.
Our study may deepen the understanding of the relationship between recurrent spontaneous pain and empathy in a clinical disorder characterized by cyclic episodes of pain.
This letter presents a <inline-formula> <tex-math notation="LaTeX">{K} </tex-math></inline-formula>-/ Ka -band gallium arsenide (GaAs) low-noise amplifier (LNA) for high dynamic range (DR) radar ...systems. The proposed LNA adopts a two-stage topology to acquire a compact chip size and low power consumption. A feedback circuit is employed in the second stage to achieve a wideband gain response. A diode-based adaptive bias circuit is designed to simultaneously improve the linearity and maintain a low drain current. In the 3-dB bandwidth from 18.7 to 36.5 GHz, the LNA achieves a maximum small-signal gain of 15.9 dB and a minimum noise figure (NF) of 1.5 dB. The measured input 1-dB compression point (IP 1dB ) is higher than −1 dBm, and the measured input-referred intercept point (IIP 3 ) is higher than 3.2 dBm in the operation band. The LNA has a chip size of 1.2 mm <inline-formula> <tex-math notation="LaTeX">\times0.8 </tex-math></inline-formula> mm and the power consumption is 66 mW.
•A modeling method of Kirigami patterns based on chemical corrosion is proposed.•The proposed machine learning approach for prediction is efficient and accurate.•Multi-objective prediction including ...deformation fields and stress fields is realized using a general machine learning approach.
Kirigami-inspired designs hold great potential for the development of functional materials and devices, but predicting the morphological configuration of these structures under various loading conditions remains a challenge for traditional experimental and numerical methods. Here, we present a novel approach that utilizes machine learning algorithms to accurately predict the deformation and stress field of kirigami-inspired programmable active composites. To train our model, first, we used a chemical corrosion algorithm to generate a dataset of kirigami-inspired imaging model accompanied by utilizing finite element simulations to obtain their deformation and stress fields as the ground truth, and subsequently trained the machine learning model to offer robust predictions of the displacement and stress fields of the designated structures. The graphically preprocessing transformation between color space and deformation(stress) fields is used to match the fields prediction of mechanical problems with powerful machine learning approaches in image processing. Our results demonstrate the effectiveness of this approach in predicting the morphological and mechanical behaviors of kirigami-inspired active structures, paving the way for the development of advanced and functional composite designs that are programmable and active.
Display omitted
PDF
