The rotational frequency (RF) is an important information for multi-fault features detection of rolling bearing under varying speed conditions. In the traditional methods, such as the computed order ...analysis (COA) and the time–frequency analysis (TFA), the RF should be measured using an encoder or extracted by a complex algorithm, which bring challenge to bearing fault diagnosis. In order to address this issue, a novel iterative generalized demodulation (IGD) based method guided by the instantaneous fault characteristic frequency (IFCF) extraction and enhanced instantaneous rotational frequency (IRF) matching is proposed in this paper. Specifically, the resonance frequency band excited by bearing fault is first obtained by the band-pass filter, and its envelope time–frequency representation (TFR) is calculated using the Hilbert transform and the short-time Fourier transform (STFT). Second, the IFCF is extracted using the harmonic summation-based peak search algorithm from the envelope TFR. Third, the time-varying RF ridge is transformed into a line paralleling to the time axis using the IGD with the phase function (PF). The PF is calculated by the IFCF function and fault characteristic coefficient (FCC). Lastly, the iterative generalized demodulation spectrum (IGDS) is obtained using the fast Fourier transform (FFT) for identifying fault type corresponding to the extracted IFCF. Based on obtained fault type and FCC ratios, new PFs and frequency points (FPs) are calculated for detecting other faults. Both simulated and experimental results validate that multi-fault features of rolling bearing under time-varying rotational speeds can be effectively identified without RF measurement and extraction.
•An IGD-based bearing multi-fault diagnosis strategy under time-varying speeds conditions is proposed.•The technique is guided by IFCF extraction and enhanced RF matching.•The IGD is used to eliminate influence of rotational speed fluctuation.•The IGDS is constructed to quantitatively diagnose bearing fault.
Grasslands cover 41.7% of China's land surface and distribute mainly in NW China. To project future change of grassland fires, it is essential to explore paleofire dynamics. However, comparatively ...little is known about the patterns and driving forces of grassland fires in NW China due to the scarcity of paleorecords. Here, we present Holocene sedimentary records of grassland fire and vegetation in westerly‐dominated Xinjiang (NW China) to examine fire‐fuel‐climate interactions. We find that grassland fire regime is fuel‐limited, consistent with other grasslands worldwide. We reveal that burning increased throughout the Holocene, due to increasing moisture, grass cover, fuel load, and temperature of spring fire season. The Holocene pattern of burning coincides with several other records nearby and a global‐scale grassland fire record. Our results are different from monsoonal China where fuel load is not a constraining factor and more (less) fires occurred during colder/drier (warmer/moister) periods in the Holocene.
Plain Language Summary
Recently, catastrophic fires occurred frequently, such as California (2018), Amazon (2019), and Australia (2020), causing tremendous losses to natural resources, human/animal lives, and socioeconomic assets. The fire risks with considerable costs are projected to increase under global warming. To estimate the effects of forthcoming climatic fluctuations on fire activity for large‐scale fire‐prone ecosystems, we need sufficient long‐term information regarding the fire‐fuel‐climate interactions on various spatial‐temporal scales. Notably, widespread grasslands make up roughly 40.5% and 41.7% of the Earth's and China's land surface, respectively. However, Holocene fire dynamics across extensive grassland areas of NW China are not well understood, owing to the scarcity of paleofire records. Here, we provide Holocene sedimentary records of grassland fire and vegetation in Xinjiang of NW China to explore the linkages among fire, fuel, and climate during the Holocene. We suggest that climatic conditions of spring fire‐season and moisture availability are essential for driving the fire‐regime evolution. We find that intensified fire activity has been caused by increased flammability (fire‐season) and enhanced cumulative biomass (fuel‐load) along with increased humidity throughout the Holocene. More importantly, we critically need more grassland paleofire records to understand long‐perspective fire dynamics of interior China.
Key Points
The study examines Holocene fire and vegetation records to explore fire‐fuel‐climate interactions in Bortala Basin of Xinjiang in NW China
Grassland fire regime is fuel‐limited and burning shows a gradually increasing trend over the last ca. 10,000 years
Relative humidity and temperature of the spring fire season are the primary drivers of fire‐regime dynamics during the Holocene
Highlights ► Necroptosis is one particular form of programmed necrosis induced by stimulating death receptors with agonists. ► Necroptosis has its own unique signaling pathway which requires the ...involvement of receptor interaction protein kinase 1 and 3. ► Necroptosis plays an important role in immune system regulation, tissue injury, and cancer development.
The poor performance and high cost of the starch-sisal fibre composites with open-cell structures prevent their usage as biodegradable biomass to replace plastics. Therefore, inorganic fillers talcum ...powder (TP), CaCO3 (CC) and a bio-filler eggshell powder (EP) were added, and the resulting mechanical properties, water resistance, thermal stability and biodegradation characteristics were compared. Results show that the tensile strength of the EP-composite increases by 34% and the compressive strength of the CC-composite increases by 69% when compared with those of the non-filler (NF) composite. The mechanical properties of the composites improved because of the reduction of starch crystallinity and the formation of new hydrogen bonds. The EP-composite offered optimal cushioning owing to its uniform and dense open-cell structures. Besides, the CC- and EP-composites offered better thermal stability. The composites with fillers were more waterproof than the NF-composite (by approximately 33%). After conducting biodegradability tests for 30 days, the EP-composite lost 67% of its mass, which was more than those associated with the TP- and CC-composites and can be attributed to the presence of organic matter in the EP-composite. These results demonstrate the potential of EP to replace CC and TP for reinforcing the starch-fibre composites with open-cell structures.
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•A filler-reinforced rapidly degradable starch-fibre composite with open-cell structures was prepared.•Both bio-fillers and inorganic fillers can improve the mechanical properties, thermal stability and water resistance.•Bio-fillers were advantageous for rapid biodegradation.•Bio-fillers (eggshell powder) have the potential to replace inorganic fillers (talcum powder and CaCO3).
In abrasive belt rail grinding, understanding the abrasive belt wear mechanisms is important for improving grinding accuracy and abrasive belt service life. Taking a single ceramic grit in a stable ...grinding state as an example, this study investigated the critical transition conditions and recognition methods between the different wear modes. Based on the crack growth equation, the critical transition condition from abrasion to fracture was modeled by calculating the stress around the cracks hiding in the grit tip. The transition condition between fracture and pull-off was determined by comparing the external stress around the grit root and the bonding strength of the resin binder. These critical conditions were verified by single grit scratching experiments and the improved Sc wear map method.
•Two recognition models to distinguish abrasive belt wear modes were established.•Critical condition from abrasion to fracture was given by crack growth equation.•Critical condition from fracture to pull off was related to grits' root stress.•An improved wear map was given to visualize and project the belt wear transition.
B cell receptor (BCR) signaling is involved in the pathogenesis of B cell malignancies. Activation of BCR signaling promotes the survival and proliferation of malignant B cells. Bruton tyrosine ...kinase (BTK) is a key component of BCR signaling, establishing BTK as an important therapeutic target. Several covalent BTK inhibitors have shown remarkable efficacy in the treatment of B cell malignancies, especially chronic lymphocytic leukemia. However, acquired resistance to covalent BTK inhibitors is not rare in B cell malignancies. A major mechanism for the acquired resistance is the emergence of BTK cysteine 481 (C481) mutations, which disrupt the binding of covalent BTK inhibitors. Additionally, adverse events due to the off-target inhibition of kinases other than BTK by covalent inhibitors are common. Alternative therapeutic options are needed if acquired resistance or intolerable adverse events occur. Non-covalent BTK inhibitors do not bind to C481, therefore providing a potentially effective option to patients with B cell malignancies, including those who have developed resistance to covalent BTK inhibitors. Preliminary clinical studies have suggested that non-covalent BTK inhibitors are effective and well-tolerated. In this review, we discussed the rationale for the use of non-covalent BTK inhibitors and the preclinical and clinical studies of non-covalent BTK inhibitors in B cell malignancies.
PD-1-PD-L1 interaction is known to drive T cell dysfunction, which can be blocked by anti-PD-1/PD-L1 antibodies. However, studies have also shown that the function of the PD-1-PD-L1 axis is affected ...by the complex immunologic regulation network, and some CD8
T cells can enter an irreversible dysfunctional state that cannot be rescued by PD-1/PD-L1 blockade. In most advanced cancers, except Hodgkin lymphoma (which has high PD-L1/L2 expression) and melanoma (which has high tumor mutational burden), the objective response rate with anti-PD-1/PD-L1 monotherapy is only ~20%, and immune-related toxicities and hyperprogression can occur in a small subset of patients during PD-1/PD-L1 blockade therapy. The lack of efficacy in up to 80% of patients was not necessarily associated with negative PD-1 and PD-L1 expression, suggesting that the roles of PD-1/PD-L1 in immune suppression and the mechanisms of action of antibodies remain to be better defined. In addition, important immune regulatory mechanisms within or outside of the PD-1/PD-L1 network need to be discovered and targeted to increase the response rate and to reduce the toxicities of immune checkpoint blockade therapies. This paper reviews the major functional and clinical studies of PD-1/PD-L1, including those with discrepancies in the pathologic and biomarker role of PD-1 and PD-L1 and the effectiveness of PD-1/PD-L1 blockade. The goal is to improve understanding of the efficacy of PD-1/PD-L1 blockade immunotherapy, as well as enhance the development of therapeutic strategies to overcome the resistance mechanisms and unleash the antitumor immune response to combat cancer.
Facing the dual pressures of carbon mitigation and trade barrier, it is desired that variations of water footprints (WFs) with the related policy interferences be investigated in Yangtze River ...Economic Belt (YREB). In this study, a factorial equilibrium WFs model is developed to (a) tackle the interactive effects (on blue‐ and gray‐WFs) of different policy alternatives presented as multiple levels of carbon tax and import tariff; (b) explore the variations of blue‐ and gray‐WFs in specific socio‐economic sectors under multiple scenarios of the dual pressures; and (c) investigate the provincial WFs from the perspective of commodity consumption. It is found that increased import tariffs can boost the WFs of primary energy and resource‐conversion sectors, and can promote inter‐sectoral virtual‐water exchanges; carbon tax can suppress the WFs for most of the sectors, and can result in entirely declined industrial production. Moreover, carbon tax can lead to reduced water productivity in YREB, and thus exacerbate water shortage. Through this research, desired policies for water‐footprint management policies could be identified with maximized socio‐economic and environmental benefits.
Key Points
A factorial equilibrium water footprint (WF) model for exploring the contributions of multiple policy alternatives on changes in WFs is proposed
High carbon tax may sacrifice China's economy; trade barrier between China and the US may lead to negative impacts on China's food security
Carbon tax and trade barrier would reduce the blue WFs in the upper reach and would have opposite effects on the gray WFs in the lower reach
Our understanding on the spatial-temporal patterns of climatic variability over the last few millennia in the East Asian monsoon-dominated northern China (NC), and its role at a macro-scale in ...affecting the prosperity and depression of Chinese dynasties is limited. Quantitative high-resolution, regionally-synthesized palaeoclimatic reconstructions as well as simulations, and numerical analyses of their relationships with various fine-scale, numerical agro-ecological, social-economic, and geo-political historical records during the period of China's history, are presented here for NC. We utilize pollen data together with climate modeling to reconstruct and simulate decadal- to centennial-scale variations in precipitation or temperature for NC during the last 2200 years (-200–2000 AD). We find an overall cyclic-pattern (wet/warm or dry/cold) in the precipitation and temperature anomalies on centennial- to millennial-scale that can be likely considered as a representative for the entire NC by comparison with other related climatic records. We suggest that solar activity may play a key role in driving the climatic fluctuations in NC during the last 22 centuries, with its quasi ∼100, 50, 23, or 22-year periodicity clearly identified in our climatic reconstructions. We employ variation partitioning and redundancy analysis to quantify the independent effects of climatic factors on accounting for the total variation of 17 fine-grained numerical Chinese historical records. We quantitatively illustrate that precipitation (67.4%) may have been more important than temperature (32.5%) in causing the overall agro-ecological and macro-geopolitical shifts in imperial China with NC as the central ruling region and an agricultural heartland over the last 2200 years.
•A high-resolution dataset for precipitation and temperature over the last 2200 years in monsoonal northern China.•A fine-grained numerical dataset for 17 Chinese historical proxy records during the pre-industrial era.•Precipitation has been more important than temperature in causing geopolitical shifts in monsoonal northern China.
In this paper, an improved APF-GFARRT* (artificial potential field-guided fuzzy adaptive rapidly exploring random trees) algorithm based on APF (artificial potential field) guided sampling and fuzzy ...adaptive expansion is proposed to solve the problems of weak orientation and low search success rate when randomly expanding nodes using the RRT (rapidly exploring random trees) algorithm for disinfecting robots in the dense environment of disinfection operation. Considering the inherent randomness of tree growth in the RRT* algorithm, a combination of APF with RRT* is introduced to enhance the purposefulness of the sampling process. In addition, in the context of RRT* facing dense and restricted environments such as narrow passages, adaptive step-size adjustment is implemented using fuzzy control. It accelerates the algorithm's convergence and improves search efficiency in a specific area. The proposed algorithm is validated and analyzed in a specialized environment designed in MATLAB, and comparisons are made with existing path planning algorithms, including RRT, RRT*, and APF-RRT*. Experimental results show the excellent exploration speed of the improved algorithm, reducing the average initial path search time by about 46.52% compared to the other three algorithms. In addition, the improved algorithm exhibits faster convergence, significantly reducing the average iteration count and the average final path cost by about 10.01%. The algorithm's enhanced adaptability in unique environments is particularly noteworthy, increasing the chances of successfully finding paths and generating more rational and smoother paths than other algorithms. Experimental results validate the proposed algorithm as a practical and feasible solution for similar problems.
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