ARTICLE | doi:10.20944/preprints202110.0255.v1
Subject: Engineering, Mechanical Engineering Keywords: electromagnetic tuned mass damper; H2 optimization; structural vibration control; negative inductance; negative resistance.
Online: 18 October 2021 (15:37:50 CEST)
To realize structural vibration control,a two parameters H2 optimization design was proposed to optimize the tuning ratio and damping ratio for electromagnetic tuned mass damper (EMTMD). The control effect of this two parameters optimization design is better than that of classical tuned mass damper (TMD).For this two parameters optimization,the most important thing is that the inductance of the coil can be set very small and the external load resistance can be positive ,which can avoid the use of complex negative impedance circuit. If Ref. were designed according to the H2 optimization of two parameters, the EMTMD can be used for multi-modal vibration control of structures without connecting negative inductance and negative resistance spontaneously.
ARTICLE | doi:10.20944/preprints202309.0133.v1
Subject: Engineering, Aerospace Engineering Keywords: Star image registration; Radial module feature; Rotation angle feature; Robustness; Real-time
Online: 4 September 2023 (07:16:38 CEST)
Star image registration is the most important step in the application of astronomical image differencing, stacking and mosaicking, which requires high robustness, accuracy and real--time of the algorithm, but there is no high--performance registration algorithm in this field. In this paper, we propose a star image registration algorithm that relies only on radial module features (RMF) and rotation angle features (RAF), which has excellent robustness, high accuracy, and good real--time performance. The test results on a large amount of simulated and real data show that the comprehensive performance of the proposed algorithm is significantly better than the four classical baseline algorithms in the presence of rotation, insufficient overlapping area, false stars, position deviation, magnitude deviation and complex sky background, which is a more ideal star image registration algorithm.
ARTICLE | doi:10.20944/preprints202309.2024.v2
Subject: Environmental And Earth Sciences, Remote Sensing Keywords: target detection; side-scan sonar images; seabed object; frequency domain
Online: 2 November 2023 (07:13:35 CET)
Side-scan sonar (SSS) detection is a key method in applications such as underwater environmental security and subsea resource development. The use of acoustic images for seabed target detection has gradually become a mainstream underwater detection method. However, many existing detection approaches primarily concentrate on tracking the evolution path of optical image object detection tasks, resulting in complex structures and limited versatility. To tackle this issue, we introduce a pioneering Dual-Domain Multi-Frequency Network (D2MFNet) meticulously crafted to harness the distinct characteristics of SSS image detection. In D2MFNet, aiming at the underwater detection requirements of small scenes, we introduce a novel method for optimize and improve the detection sensitivity of different frequency ranges and propose a Multi-Frequency Combined Attention Mechanism (MFCAM). This mechanism amplifies the relevance of dual-domain features across different channels and space. Moreover, recognizing that SSS images can provide richer insights after frequency domain conversion, we introduce a Dual-Domain Feature Pyramid Network (D2FPN). By incorporating frequency domain information representation, D2FPN significantly augments the depth and breadth of feature information in underwater small datasets. Our methods are seamlessly designed for integration into existing networks, offering plug-and-play functionality with substantial performance enhancements. We have conducted extensive experiments to validate the efficacy of our proposed techniques, and the results showcase their state-of-the-art performance. MFCAM improves the mAP by 16.9% in the KLSG dataset and 15.5% in the SCTD dataset. The mAP of D2FPN was improved by 8.4% in the KLSG dataset and by 9.8% in the SCTD dataset. We will make our code and models publicly available at https://dagshub.com/estrellaww00/D2MFNet.
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: Novel coronavirus pneumonia; COVID-19; SARS-CoV-2; Pathology; Critical patient
Online: 9 March 2020 (10:31:10 CET)
Background Critical patients with novel coronavirus pneumonia ( COVID-19) have worse outcome and high mortality. However, the histopathology of critical patient with COVID-19 remains undisclosed. Methods We performed the whole lung biopsy, and described the pathological changes of critical COVID-19 patient done with transplant by HE staining, immunohistochemistry and special staining observed under the microscopy. Findings The whole lungs displayed diffuse congestive appearance and partly haemorrhagic necrosis on gross examination. The haemorrhagic necrosis was prominently present in outer edge of the right lower lung. The cut surfaces of the lung displayed severe congestive and haemorrhagic changes. The main pathological changes showed massive pulmonary interstitial fibrosis, and partly hyaline degeneration, variable degrees of hemorrhagic pulmonary infarction. Small vessels hyperplasia, vessel wall thickening, lumen stenosis, occlusion and microthrombosis formation. Focal monocytes, lymphocytes and plasma cells infiltrating into pulmonary interstitium. Bronchiolitis and alveolitis with proliferation, atrophy, desquamation and squamous metaplasia of epithelial cells. Atrophy, vacuolar degeneration, proliferation, desquamation and squamous metaplasia in alveolar epithelial cells. Alveolar cavity congestion was prominent, and contained mucus, edema fluid, desquamated epithelial cells, and inflammatory cells. We also found several multinucleate giant cells and intracytoplasmic viral inclusion bodies. Special stains including Masson stain, sirius red staining, reticular fibers staining indicated massive pulmonary interstitial fibrosis. Immunohistochemistry showed positive for immunity cells including CD3, CD4, CD8, CD20, CD79a, CD5, CD38 and CD68. Interpretation We demonstrate the pathological findings of critical patient with COVID-19, which might provide a deep insight of the pathogenesis and severity of this disease.
ARTICLE | doi:10.20944/preprints202311.0810.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: cut chrysanthemum; continuous cropping wilt; pathogen invasion; plant physiological response; rhizosphere microorganisms
Online: 14 November 2023 (05:26:04 CET)
Cut chrysanthemum, renowned as a highly favored floral choice globally, experiences a significant decline in production due to the practice of continuous cropping. The adverse physiological effects on cut chrysanthemums have been observed as a result of the degradation of soil physical and chemical properties, coupled with the proliferation of pathogens. It is noteworthy that the 'Guangyu' cultivar in Xinxiang, Henan province, China, has been specifically impacted by these effects. This study effectively identified and validated the precise pathogen accountable for wilt disease initially. Subsequently, an analysis was conducted to examine the invasion pattern of the pathogen and the physiological response of the chrysanthemum. Finally, PacBio platform was employed to investigate the dynamic alterations in the microbial community within the soil rhizosphere, comparing the effects of seven years of monocropping with the first year. The findings indicated that Fusarium solani was the primary causative agent responsible for wilt disease, as it possessed the ability to invade and establish colonies in plant roots, leading to alterations in various physiological parameters of the plants. Furthermore, the practice of continuous cropping had been observed to significantly disturb the microbial community composition, potentially acting as an additional influential factor in the advancement of wilt.
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: storage tank; continuous real–time; release model; leakage test; hole discharge
Online: 8 July 2019 (04:34:54 CEST)
The calculation of the release of liquid hazardous chemicals storage tanks is an important part of the quantitative risk assessment of accidents. This paper mainly establishes a continuous real–time release model based on the instantaneous mass flow Qm model. Meanwhile, the software function module was analyzed, and programming software was developed using C# language for model solving. A series of experiments for repeated leakage tests was designed and the discharges through three small holes with different heights for 200 s were observed. The results show that the continuous real–time leakage model is effective, and the deviation between theoretical and experimental release amounts are within a reasonable range. The higher the liquid level above the leak hole is, and the smaller the height of the leak hole from the ground is, the greater the flow rate at the leak orifice is and the smaller discharge rate change is. Therefore, the deviation between the theoretical release amount Mt and the experimental average release amount Ma is greater while the height of the leak hole from the ground is smaller, which indicates that the smaller the distance from the leak orifice to the ground, the greater the influence of the empirical discharge coefficient C0 on the release amount M.
ARTICLE | doi:10.20944/preprints202311.0071.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: material distribution; digital twin; scheduling model; scheduling mechanism; improved ACO
Online: 2 November 2023 (04:48:50 CET)
. Manufacturers are increasingly adopting mixed-flow manufacturing models to meet the growing customized, diverse, and dynamic customer demand. In such an environment, material distribution scheduling optimization is vital for smooth operations and is integral to production management. However, manufacturers frequently encounter problems like disordered and delayed material distribution. Traditional scheduling methods suffer from problems like inadequate transparency, delayed decision directives, and suboptimal results, impacting performance. To this end, this study proposes a dynamic material distribution scheduling optimization model and strategy based on digital twin (DT) to address these problems. Firstly, we introduce workstation satisfaction and establish a material distribution path optimization model minimizing total distribution cost while maximizing workstation satisfaction. Subsequently, we present a cloud-edge computing-based decision framework and explain the DT-based material distribution system's components and operation. Furthermore, a dynamic material distribution scheduling optimization mechanism based on DT is designed. By incorporating a savings method and incentive, penalty strategies, improvements are made to the path node selection probabilities and the information pheromone update rules of the traditional ant colony optimization (ACO) algorithm. Finally, a numerical case study, using real data from collaborating enterprises, validates the proposed algorithm and strategy. This research offers valuable insights into logistics management and algorithm design in smart manufacturing environments.
ARTICLE | doi:10.20944/preprints202003.0308.v1
Online: 20 March 2020 (07:01:44 CET)
Novel coronavirus (COVID-19) can lead to multiple organ injuries such as acute respiratory distress syndrome (ARDS), acute renal injury (AKI) and so on. ACE2 is an important part of the renin-angiotensin system (RAS) and a key protein needed for COVID-19 to invade cells. First of all, we searched the HPA, GTEx and FANTOM5 Databases and found that the expression of ACE2 in kidney tissue was significantly higher than that in lung tissue. Then, by searching the Nephroseq Database, it is further verified that ACE2 is highly expressed in renal tissue and plays a protective role in renal tissue. However, current studies have found that the incidence of AKI caused by COVID-19 is much lower than that of ARDS. Because of this, we further searched the proteins interacting with ACE2 protein through the STING Database and analyzed the expression of tissue protein mRNA in the HPA Database. It was noted that AGTR2 mRNA was highly expressed in lung tissue, but low in kidney tissue, and hard tissue specificity in lung tissue. Through further research, it is found that AGTR2 plays a major role in the development of pulmonary fibrosis. Therefore, AGTR2 may be a key protein in COVID-19 pneumonia, and AGTR2 may be a potential new therapeutic target for the treatment of COVID-19 patients.
ARTICLE | doi:10.20944/preprints201906.0088.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: ricin; marker peptides; unambiguous identification; mass spectrometry
Online: 11 June 2019 (08:27:32 CEST)
Both ricin and R. communis agglutinin (RCA120), belonging to the type II ribosome-inactivating proteins (RIPs-Ⅱ), are derived from the seeds of castor bean plant. They share very similar amino acid sequences, but ricin is much more toxic than RCA120. It is urgently necessary to distinguish ricin and RCA120 in response to public safety. Currently, mass spectrometric assays are well established for unambiguous identification of ricin by accurate analysis of differentiated amino acid residues after trypsin digestion. However, diagnostic peptides are relatively limited for unambiguous identification of trace ricin, especially in complex matrices. Here, we demonstrate a digestion strategy of multiple proteinases to produce novel peptide markers for unambiguous identification of ricin. LC-HRMS was used to verified the resulting peptides, among which only the peptides with uniqueness and good MS response were selected as peptide markers. Seven novel peptide markers were obtained from tandem digestion of trypsin and endoproteinase Glu-C in PBS buffer. From the chymotrypsin digestion under reduction and non-reduction conditions, eight and seven novel peptides were selected respectively. Using pepsin under pH 1~2 and proteinase K digestion, 6 and 5 peptides were selected as novel peptide markers. In conclusion, the obtained novel peptides from the established digestion methods can be recommended for the unambiguous identification of ricin during the investigation of illegal use of the toxin.
ARTICLE | doi:10.20944/preprints202306.1549.v1
Subject: Chemistry And Materials Science, Physical Chemistry Keywords: Lithium-ion battery; thermal runaway,; gas emission,; cell result multiplication
Online: 21 June 2023 (12:10:40 CEST)
Thermal safety of lithium-ion traction batteries is a highly concerned issue in the field of electric transportation. The large amount of gas emission during the thermal runaway process of batteries has highly safety hazards such as fire and explosion. Quantitative analysis of emission is one of the important challenges for testing and evaluating battery safety. Focus on quantifying the gas emission through large-scale thermal propagation in battery modules and packs, based on the idea of cell result multiplication, this article conducts thermal runaway emission analysis on single cell and modules, and compares the behavior of thermal runaway and gas emission of the cell and module from the aspects of temperature, pressure, gas composition and battery morphology. The feasibility of the cell result multiplication method was verified from the perspective of experimental data.
Subject: Biology And Life Sciences, Virology Keywords: COVID-19; coronavirus; fulminant myocarditis; infection; echocardiography.
Online: 7 April 2020 (01:03:22 CEST)
Background: Coronavirus Disease 2019 (COVID-19) has been demonstrated to be the cause of pneumonia. Nevertheless, it has not been reported as the cause of acute myocarditis or fulminant myocarditis. Case presentation: A 63-year-old male was admitted with pneumonia and cardiac symptoms. He was genetically confirmed as having COVID-19 according to sputum testing on the day of admission. He also had elevated troponin I (Trop I) level (up to 11.37 g/L) and diffuse myocardial dyskinesia along with a decreased left ventricular ejection fraction (LVEF) on echocardiography. The highest level of interleukin-6 was 272.40 pg/ml. Bedside chest radiographs showed typical ground-glass changes indicative of viral pneumonia. Laboratory test results for viruses that cause myocarditis were all negative. The patient conformed to the diagnostic criteria of the Chinese expert consensus statement for fulminant myocarditis. After receiving antiviral therapy and mechanical life support, Trop I was reduced to 0.10 g/L, and interleukin-6 was reduced to 7.63 pg/ml. Moreover, the LVEF of the patient gradually recovered to 68%. The patient died of aggravation of secondary infection on the 33rd day of hospitalization. Conclusion: COVID-19 patients may develop severe cardiac complications such as myocarditis and heart failure. This is the first report of COVID-19 complicated with fulminant myocarditis. The mechanism of cardiac pathology caused by COVID-19 needs further study.
ARTICLE | doi:10.20944/preprints202110.0284.v1
Subject: Biology And Life Sciences, Ecology, Evolution, Behavior And Systematics Keywords: Watershed; biogeographic patterns; microbial biogeography; biodiversity; spatial distribution; research unit
Online: 20 October 2021 (09:34:27 CEST)
Biogeography research is flawed by the poor understanding of microbial distributions due to the lack of a systematic research framework, especially regarding appropriate study units. By combining pure culture and molecular methods, we studied the biogeographic patterns of nematode-trapping fungi by collecting and analysing 2,250 specimens from 228 sites in Yunnan Province, China. We found typical watershed patterns at the species and genetic levels of nematode-trapping fungi. The results showed that microbial biogeography could be better understood by 1) using watersheds as research units, 2) removing the coverup of widespread species, and 3) applying good sampling efforts and strategies. We suggest that watersheds could help unify the understanding of the biogeographic patterns of animals, plants, and microbes and may also help account for the historical and contemporary factors driving species distributions.
ARTICLE | doi:10.20944/preprints201703.0126.v1
Subject: Chemistry And Materials Science, Metals, Alloys And Metallurgy Keywords: 5754 Aluminum alloy; Two-pass hot compression; Dynamic softening; Metadynamic recrystallization
Online: 16 March 2017 (18:28:52 CET)
Isothermal interrupted hot compression tests of 5754 aluminum were conducted on Gleeble-3500 thermo-mechanical simulator at temperature 350 °C and 450 °C, strain rate 0.1 s-1 and 1s−1. These tests simulated flat rolling to investigate how softening behaviors respond to controlled parameters, such as deformation temperature, strain rate and delay times. This data allowed the parameters for the hot rolling process to be optimized. The delay times during interrupted compression vary between 5s and 60s. The dynamic softening at each pass and metadynamic recrystallization at the intervals of deformation passes were analyzed in detail. 0.2% offset yield strength is applied to calculate the softening fraction undergoing metadynamic recrystallization. A kinetic model was developed to describe metadynamic recrystallization behaviors of the hot deformed 5754 aluminum alloy. Furthermore, the time constant for 50% recrystallization was expressed as functions related to the temperature and the strain rate. The experimental and calculated results were found to be in close agreement, which verified the developed model.