Linear active disturbance rejection control of waste heat recovery systems with organic Rankine cycles

In this paper, a linear active disturbance rejection controller is proposed for a waste heat recovery system using an organic Rankine cycle process, whose model is obtained by applying the system identification technique. The disturbances imposed on the waste heat recovery system are estimated through an extended linear state observer and then compensated by a linear feedback control strategy. The proposed control strategy is applied to a 100 kW waste heat recovery system to handle the power demand variations of grid and process disturbances. The effectiveness of this controller is verified via a simulation study, and the results demonstrate that the proposed strategy can provide satisfactory tracking performance and disturbance rejection

Monitoring the Degradation of Island Permafrost Using Time-Series InSAR Technique: A Case Study of Heihe, China

In the context of global warming, the air temperature of the Heihe basin in Northeast China has increased significantly, resulting in the degradation of the island permafrost. In this paper, we used an elaborated time-series Interferometric Synthetic Aperture Radar (InSAR) strategy to monitor the ground deformation in the Heihe area (Heilongjiang Province, China) and then analyzed the permafrost deformation characteristics from June 2007 to December 2010. The results showed that the region presented island permafrost surface deformation, and the deformation rate along the line of sight mainly varied from –70 to 70 mm/a. Based on the analysis of remote sensing and topological measurements, we found that the deformation area generally occurred at lower altitudes and on shady slopes, which is consistent with the distribution characteristics of permafrost islands. Additionally, the deformation of permafrost is highly correlated with the increase of annual minimum temperature, with an average correlation value of –0.80. The accelerated degradation of permafrost in the study area led to the settlement, threatening the infrastructure safety. Our results reveal accelerated degradation characteristics for the island permafrost under the background of rising air temperature, and provide a reference for future relevant research

Direct and Rapid High-Temperature Upcycling of Degraded Graphite

Recycling the degraded graphite is becoming increasingly important, which can helped conserve natural resources, reduce waste, and provide economic and environmental benefits. However, current regeneration methods usually suffer from the use of harmful chemicals, high energy and time consumption, and poor scalability. Herein, we report a continuously high-temperature heating (≈2000 K) process to directly and rapidly upcycle degraded graphite containing impurities. A sloped carbon heater is designed to provide the continuous heating source, which enables robust control over the temperature profile, eliminating thermal barrier for heat transfer compared to conventional furnace heating. The upcycling process can be completed within 0.1 s when the degraded graphite rolls down the sloped heater, allowing us to produce the upcycled graphite on a large scale. High-temperature heating removes impurities and enhances the graphitization degree and (002) interlayer spacing, making the upcycled graphite more suitable for lithium intercalation and deintercalation. The assembled upcycled graphite||Li cell displays a high reversible capacity of ≈320 mAh g−1 at 1 C with a capacity retention of 96% after 500 cycles, comparable to current state-of-the-art recycled graphite. The method is a chemical-free, rapid, and scalable way to upcycle degraded graphite, and is adaptable to recycle other electrode materials.https://doi.org/10.1002/adfm.20230295

Carbon-Tailored Semimetal MoP as an Efficient Hydrogen Evolution Electrocatalyst in Both Alkaline and Acid Media

The electrolysis processes such as hydrogen evolution reaction (HER) require high efficient catalysts with robust surface stability. A high conductivity is also necessary to speed up the charge transport between the catalyst and the electrolyte. Recently, the observation of exceedingly high conductivity in the topological semimetal MoP, has provided a model catalyst to investigate the correlation between the electrical transport and the electrocatalytic activity for the HER. Thus, MoP is encapsulated in a Mo, P codoped carbon layer (MoP@C). This composite material exhibits outstanding HER performance, with an extremely low overpotential of 49 mV at a current density of 10 mA cm(-2) and a Tafel slope of 54 mV dec(-1) in an alkaline medium. In addition, electron transport analysis indicates that MoP exhibits high conductivity and mobility due to the existence of triple-point fermions and a complex Fermi surface. Furthermore, the presence of P-C and Mo-C bonds at the interface between the carbon layer and the MoP particles modulates the band structure of MoP@C and facilitates fast electron transfer, accumulation, and subsequent delocalization, which are in turn responsible for the excellent HER activity

Probing CENP-E function in chromosome dynamics using small molecule inhibitor syntelin

International audienc

Health economic assessment of Gd-EOB-DTPA MRI versus ECCM-MRI and multi-detector CT for diagnosis of hepatocellular carcinoma in China

<div><p>Limited data exists in China on the comparative cost of gadolinium ethoxybenzyl diethylenetriamine magnetic resonance imaging (Gd-EOB-DTPA-MRI) with other imaging techniques. This study compared the total cost of Gd-EOB-DTPA-MRI with multidetector computed tomography (MDCT) and extracellular contrast media–enhanced MRI (ECCM-MRI) as initial imaging procedures in patients with suspected hepatocellular carcinoma (HCC). We developed a decision-tree model on the basis of the Chinese clinical guidelines for HCC, which was validated by clinical experts from China. The model compared the diagnostic accuracy and costs of alternative initial imaging procedures. Compared with MDCT and ECCM-MRI, Gd-EOB-DTPA-MRI imaging was associated with higher rates of diagnostic accuracy, i.e. higher proportions of true positives (TP) and true negatives (TN) with lower false positives (FP). Total diagnosis and treatment cost per patient after the initial Gd-EOB-DTPA-MRI evaluation was similar to MDCT (¥30,360 vs. ¥30,803) and lower than that reported with ECCM-MRI (¥30,360 vs. ¥31,465). Lower treatment cost after initial Gd-EOB-DTPA-MRI was driven by reduced utilization of confirmatory diagnostic procedures and unnecessary treatments. The findings reported that Gd-EOB-DTPA-MRI offered higher diagnostic accuracy compared with MDCT and ECCM-MRI at a comparable cost, which indicates Gd-EOB-DTPA-MRI could be the preferred initial imaging procedure for the diagnosis of HCC in China.</p></div

High-Purity Fe₃S₄ Greigite Microcrystals for Magnetic and Electrochemical Performance

High-purity Fe₃S₄ (greigite) microcrystals with octahedral shape were synthesized via a simple hydrothermal method using a surfactant. The as-prepared samples have the inverse spinel structure with high crystallinity. The saturation magnetization (<i>M</i>_s) reaches 3.74 μ_B at 5 K and 3.51 μ_B at room temperature, which is larger than all reported values thus far. Electrical transport measurements show metallic behavior with a resistivity 40 times lower than in any previous report. The potential use of greigite as an anode in lithium-ion batteries was investigated by cyclic voltammery and galvanostatic discharge–charge cycling on as-prepared samples. The discharge capacity was 1161 mAh/g in the first cycle and 563 mAh/g in the 100th cycle. This excellent electrochemical performance can be attributed to the high purity, crystallinity, and favorable morphology of the products