305 research outputs found
Anti-rollover control of a heavy-duty vehicle based on lateral load transfer rate
With the rapid development of the highway network construction and heavy-duty vehicle market, the rollover accidents of heavy-duty vehicle continue to increase. In order to improve rollover stability of vehicle, a four degree of freedom (DOF) heavy-duty vehicle model is established. An anti-rollover control strategy is designed by using differential braking system to control the lateral load transfer rate (LTR). The dynamic simulation of vehicle with and without control is fulfilled in Matlab/Simulink. Then, the vehicle responses under typical angle step input are compared and analyzed with different road surface adhesion coefficient, vehicle speed, steering wheel angle and vehicle load. The results show that the proposed control strategy is able to improve vehicle rollover stability greatly and is also beneficial to vehicle yaw stability. The increase of road surface adhesion coefficient, vehicle speed, steering wheel angle or vehicle load has positive correlation with the rollover control effect
A bead sequence-driven deposition pattern evaluation criterion for lowering residual stresses in additive manufacturing
Deposition patterns can significantly influence the distribution and magnitude of residual stress in additively manufactured parts. Time-consuming thermal-mechanical simulations and costly experimental studies are often required to identify the optimal patterns. A simple and generic method to evaluate and optimize the deposition pattern for the purpose of minimizing residual stress is in urgent need. To overcome the shortcomings of the current practice, here we propose a novel pattern evaluation criterion. Starting from the discretization of the deposition pattern by a series of sequence numbers, we introduce two interconnected concepts. The first is called âequivalent bead sequence numberâ which can be physically interpreted as an index of the localized heat accumulation induced by the deposition process. Based on this point-wise âequivalent bead sequence numberâ, the second concept called âbead sequence number dispersion indexâ which can be considered as a representation of the global heat accumulation gradient, is proposed as a criterion for assessing the resulting residual stress. The temperature fields and residual stresses of a square part with six typical deposition patterns predicted by thermo-mechanical finite element simulations are used to develop and verify the proposed criterion. It is found that the âequivalent bead sequence numberâ of a given pattern is closely correlated to the distribution of the associated temperature and residual stress. More interestingly, both the highest equivalent and highest maximum principal residual stress of a pattern linearly increase with its corresponding value of âbead sequence number dispersion indexâ. Guided by this relation, two new patterns with lower residual stress are developed and evaluated. Among all the patterns considered, the so-called S pattern shows the lowest value of the âbead sequence number dispersion indexâ which corresponds to the lowest residual stress. The proposed sequence-driven approach provides a new candidate for real-time evaluation and optimization of the deposition pattern in additive manufacturing.publishedVersio
A method for determining the ductile damage parameters of high strength steels and weld metal
The microvoid based Gurson-Tvergaard-Needleman (GTN) model is a powerful tool for predicting ductile fracture behavior, and application of such model to steels and welds needs the identification of microvoid related damage parameters. Currently, there is no standard damage parameter identification method available. In this study the previously proposed complete Gurson model (CGM) where a physical void coalescence mechanism is incorporated into the GTN model is revisited. According to the CGM, the void nucleation process dictates ductile fracture. By adopting the cluster nucleation model with an effective initial void volume fraction as the only controlling parameter, a method is proposed to explicitly determine the effective initial void volume fraction from the strain at maximum load and strain at fracture of a specially designed notched tensile specimen. The proposed equation has been experimentally verified by applying to three high strength materials, including a X80 pipeline steel and associated weld metal, and a 15CrMo steel. A general procedure for damage parameter identification is also suggested. It is argued that the obtained effective initial void volume fraction can be treated as a type of material ductility indicator.A method for determining the ductile damage parameters of high strength steels and weld metalpublishedVersio
Effect of heat input on nanomechanical properties of wire-arc additive manufactured Al 4047 alloys
Heat input is one of the most important process parameters during additive manufacturing (AM). It is of great significance to understand the effect of heat input on the microstructure and nanomechanical properties, as well as the underlying mechanisms. Wire-arc additive manufactured (WAAM-ed) Al 4047 alloys under different heat inputs were produced and studied in this work. The as-manufactured Al alloys showed hypoeutectic microstructure that consisted of primary Al (Îą-Al) dendrite and ultrafine AlâSi eutectic. The effect of heat input on hardness and strain rate sensitivity (SRS) were investigated through nanoindentation. The nanohardness decreased with the increasing heat input, in accordance with the trend of yield strength and microhardness in the previous studies, in which the mechanism was usually explained by the grain growth model and Hall-Petch relationship. This work suggests a distinct mechanism regarding the effect of heat input on nanohardness, which is the enhanced solid solution strengthening produced by lower heat input. In addition, the heat input had little effect on the SRS and activation volume. It is hoped that this study leads to new insights into the understanding of the relation between heat input and nanomechanical properties, and further benefits to improve the targeted mechanical properties and engineering applications of the AM-ed materials.publishedVersio
Maliciously Secure Circuit-PSI via SPDZ-Compatible Oblivious PRF
Circuit Private Set Intersection (Circuit-PSI) allows two parties to compute any functionality on items in the intersection of their input sets without revealing any information about the intersection set. It is a well-known variant of PSI and has numerous practical applications. However, existing circuit-PSI protocols only provide security against \textit{semi-honest} adversaries. One straightforward solution is to extend a pure garbled-circuit-based PSI (NDSS\u2712) to a maliciously secure circuit-PSI, but it will result in non-concrete complexity. Another is converting state-of-the-art semi-honest circuit-PSI protocols (EUROCRYPT\u2721; PoPETS\u2722) to be secure in the malicious setting. However, it will come across \textit{the consistency issue} since parties can not guarantee the inputs of functionality stay unchanged as obtained from the last step.
This paper addresses the aforementioned issue by introducing the first maliciously secure circuit-PSI protocol. The central building block named Distributed Dual-key Oblivious PRF (DDOPRF), provides an oblivious evaluation of secret-shared inputs with dual keys. Additionally, we ensure the compatibility of DDOPRF with SPDZ, enhancing the versatility of our circuit-PSI protocol. Notably, our construction allows us to guarantee fairness within circuit-PSI effortlessly. Importantly, our circuit-PSI protocol also achieves online linear computation and communication complexities
Effects of Reheating Methods on the Quality of Prepared Pork Rib Soup with Carrot and Corn
In order to investigate the effects of different reheating methods (microwave, steam, water bath, and open flame) on the quality of quick-frozen prepared pork rib soup with carrot and corn, heating characteristics, texture, soup color, taste substances, volatile components, and sensory quality were determined. The results demonstrated that microwave reheating was the most efficient, providing uniform heating. In terms of texture, microwave and water bath reheating had less effects on the hardness, stickiness, and meat firmness of pork ribs, while microwave and open-flame reheating maintained the hardness and stickiness of corn and carrot significantly better (P < 0.05). The steam reheated soup was golden and clear in color, whereas the open-flame reheat soup became thick and milky white due to oil emulsification. The steam reheated soup exhibited a good combination of umami amino acids and nucleotides, presenting the strongest umami taste with an equivalent umami concentration (EUC) of 178.4 g/100 g, followed by those reheated by microwave, open flame, and water bath (EUC of 109.9, 100.2, and 56.5 g/100 g, respectively). A total of 61 volatile components were identified across all samples. In total, 29, 33 and 32 volatile components were found in the microwave, steam and open-flame reheated samples, respectively, with aromatic substances being the major ones; 31 volatile components in the water bath reheated sample, alcohols being the major ones. There were significant differences in the contents of some volatile components (P < 0.05). Sensory evaluation showed that the microwave and steam reheated soups were more favored by consumers in terms of color and taste (P < 0.05), with the highest overall sensory score. In summary, steam and microwave reheating are ideal reheating methods for frozen pork rib soup with carrot and corn
Transcriptome profiling of genes regulated by phosphate-solubilizing bacteria Bacillus megaterium P68 in potato (Solanum tuberosum L.)
The insoluble phosphorus in the soil is extremely difficult to be absorbed and used directly through the potato root system. Although many studies have reported that phosphorus-solubilizing bacteria (PSB) can promote plant growth and uptake of phosphorus, the molecular mechanism of phosphorus uptake and growth by PSB has not been investigated yet. In the present study, PSB were isolated from rhizosphere soil in soybean. The data of potato yield and quality revealed that the strain P68 was the most effective In the present study, PSB identification, potato field experiment, pot experiment and transcriptome profiling to explored the role of PSB on potato growth and related molecular mechanisms. The results showed that the P68 strain (P68) was identified as Bacillus megaterium by sequencing, with a P-solubilizing ability of 461.86âmg¡Lâ1 after 7-day incubation in National Botanical Research Instituteâs Phosphate (NBRIP) medium. Compared with the control group (CK), P68 significantly increased the yield of potato commercial tubers by 17.02% and P accumulation by 27.31% in the field. Similarly, pot trials showed that the application of P68 significantly increased the biomass, total phosphorus content of the potato plants, and available phosphorus of the soil up by 32.33, 37.50, and 29.15%, respectively. Furthermore, the transcriptome profiling results of the pot potato roots revealed that the total number of bases was about 6G, and Q30 (%) was 92.35â94.8%. Compared with the CK, there were a total of 784 differential genes (DEGs) regulated when treated with P68, which 439 genes were upregulated and 345 genes were downregulated. Interestingly, most of the DEGs were mainly related to cellular carbohydrate metabolic process, photosynthesis, and cellular carbohydrate biosynthesis process. According to the KEGG pathway analysis, a total of 46 categorical metabolic pathways in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database were annotated to 101 DEGs found in potato roots. Compared with the CK, most of the DEGs were mainly enriched in glyoxylate and dicarboxylate metabolism (sot00630), nitrogen metabolism (sot00910), tryptophan metabolism (sot00380), and plant hormone signal transduction (sot04075), and these DEGs might be involved in the interactions between Bacillus megaterium P68 and potato growth. The qRT-PCR analysis of differentially expressed genes showed that inoculated treatments P68 significantly upregulated expression of the phosphate transport, nitrate transport, glutamine synthesis, and abscisic acid regulatory pathways, respectively, and the data from qRT-PCR were consistent with that obtained from RNA-seq. In summary, PSB may be involved in the regulation of nitrogen and phosphorus nutrition, glutaminase synthesis, and abscisic acid-related metabolic pathways. This research would provide a new perspective for studying the molecular mechanism of potato growth promotion by PSB in the level of gene expression and related metabolic pathways in potato roots under the application of Bacillus megaterium P68
11β-HSD1 inhibition ameliorates metabolic syndrome and prevents progression of atherosclerosis in mice
The enzyme 11βâhydroxysteroid dehydrogenase (HSD) type 1 converts inactive cortisone into active cortisol in cells, thereby raising the effective glucocorticoid (GC) tone above serum levels. We report that pharmacologic inhibition of 11β-HSD1 has a therapeutic effect in mouse models of metabolic syndrome. Administration of a selective, potent 11β-HSD1 inhibitor lowered body weight, insulin, fasting glucose, triglycerides, and cholesterol in diet-induced obese mice and lowered fasting glucose, insulin, glucagon, triglycerides, and free fatty acids, as well as improved glucose tolerance, in a mouse model of type 2 diabetes. Most importantly, inhibition of 11β-HSD1 slowed plaque progression in a murine model of atherosclerosis, the key clinical sequela of metabolic syndrome. Mice with a targeted deletion of apolipoprotein E exhibited 84% less accumulation of aortic total cholesterol, as well as lower serum cholesterol and triglycerides, when treated with an 11β-HSD1 inhibitor. These data provide the first evidence that pharmacologic inhibition of intracellular GC activation can effectively treat atherosclerosis, the key clinical consequence of metabolic syndrome, in addition to its salutary effect on multiple aspects of the metabolic syndrome itself
International expert consensus on diagnosis and treatment of lung cancer complicated by chronic obstructive pulmonary disease
Background: Lung cancer combined by chronic obstructive pulmonary disease (LC-COPD) is a common comorbidity and their interaction with each other poses significant clinical challenges. However, there is a lack of well-established consensus on the diagnosis and treatment of LC-COPD. Methods: A panel of experts, comprising specialists in oncology, respiratory medicine, radiology, interventional medicine, and thoracic surgery, was convened. The panel was presented with a comprehensive review of the current evidence pertaining to LC-COPD. After thorough discussions, the panel reached a consensus on 17 recommendations with over 70% agreement in voting to enhance the management of LC-COPD and optimize the care of these patients. Results: The 17 statements focused on pathogenic mechanisms (n=2), general strategies (n=4), and clinical application in COPD (n=2) and lung cancer (n=9) were developed and modified. These statements provide guidance on early screening and treatment selection of LC-COPD, the interplay of lung cancer and COPD on treatment, and considerations during treatment. This consensus also emphasizes patient-centered and personalized treatment in the management of LC-COPD. Conclusions: The consensus highlights the need for concurrent treatment for both lung cancer and COPD in LC-COPD patients, while being mindful of the mutual influence of the two conditions on treatment and monitoring for adverse reactions
Cryptosporidiosis caused by Cryptosporidium parvum subtype IIdA15G1 at a dairy farm in Northwestern China
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