The Piston Slap Force Reconstruction of Diesel Engine Using WOA-VMD and Deconvolution.

In a diesel engine, piston slap commonly occurs concurrently with fuel combustion and serves as the main source of excitation. Although combustion pressure can be measured using sensors, determining the slap force is difficult without conducting tests. In this study, we propose a method to identify the slap force of the piston to solve this difficult problem. The traditional VMD algorithm easily receives noise interference, which affects the value of parameter combination [k, α] and thus affects the extraction accuracy of the algorithm. First, we obtain the transfer function between the incentive and vibration response through percussion tests. Secondly, a variational modal decomposition method based on whale algorithm optimization is used to separate the slap response from the surface acceleration of the block. Finally, we calculated the slap force using the deconvolution method. Deconvolution is a typical inverse problem of mathematics, often prone to ill-conditioning, and the singular value decomposition and regularization method is used to overcome this flaw and improve accuracy. The proposed method provides an important means to evaluate the angular distribution of the slap force, identify the shock positions on the piston liner, and determine the peak value of the waveform which helps us analyze the vibration characteristics of the piston and optimize the structural design of the engine.

Adaptive Convolution Sparse Filtering Method for the Fault Diagnosis of an Engine Timing Gearbox.

Due to the superior robustness of outlier signals and the unique advantage of not relying on a priori knowledge, Convolution Sparse Filtering (CSF) is drawing more and more attention. However, the excellent properties of CSF is limited by its inappropriate selection of the number and length of its filters. Therefore, the Adaptive Convolution Sparse Filtering (ACSF) method is proposed in this paper to implement an end-to-end health monitoring and fault diagnostic model. Firstly, a novel metric entropy-time function (He-T) is proposed to measure the accuracy and efficiency of signals filtered by the CSF. Then, the filtered signal with the minimum He-T is detected with particle swarm optimization. Finally, the failure mode is diagnosed according to the envelope spectrum of the signal with minimum He-T. The effectiveness and efficiency of the ACSF is demonstrated through the experiment. The results indicate the ACSF can extract the failure characteristic of the gearbox.

Effects of Nonthermal Plasma on Microstructure and Oxidation Characteristics of Particulate Matter.

To investigate the effect of nonthermal plasma (NTP) on the microstructure and oxidation characteristics of particulate matter (PM) from diesel engines at different oxidation stages, a self-designed NTP reactor was used to conduct a time-varying oxidation test on PM samples. The oxidized PM samples were analyzed via thermogravimetric analysis and Raman spectroscopy. The results indicated that the effect of NTP could allow the elemental carbon (EC) to more easily start ignition. The oxidation activity of the EC decreased when the action time of the NTP was less than 5 min. Conversely, when the NTP action time was more than 5 min, the EC oxidation activity gradually increased. When the NTP was active for more than 10 min, it rapidly reacted with the EC, and the oxidation priority of the volatile fraction was higher than that of the EC. During the oxidation process, there are many forms of carbon structures in the particles and they have a mutual transmission relationship. The variation trend of the graphitization degree was consistent with that of the thermogravimetric results, indicating that the degree of graphitization directly affected the PM oxidation activity.

The impact of thermal pretreatment on phytochemical profiles and bioactivity of freeze-dried lily bulbs (Lilium lancifolium).

Lily bulbs are susceptible to deterioration during storage if improperly handled. To resolve this problem, it is necessary to investigate suitable processing techniques. The aim of this study is to evaluate the effects of steaming, blanching and microwave pretreatment on freeze-dried lily bulbs in terms of color, phenolic content and bioactivity. Results showed that appropriate steaming and blanching pretreatment could contribute to product characteristics similar to those of freeze-dried lily bulbs, with the maximum L* value reduced by only 7.57% and 0.55% respectively. Thermal pretreatment affected the retention, degradation and transformation of polyphenol, especially for regalosides. The polyphenol was closely associated with the browning of lily bulbs. Thermal processing caused the decline of regaloside A and the increase of regaloside B, which were the major phenolic monomers that can effectively inhibit the browning of lily bulbs. The antioxidant activity of freeze-dried lily pretreated with blanching for 6 min was the highest (4.39 ± 0.32 µmol TE/g DW), with an improvement of nearly 25.39% compared to that of untreated freeze-dried lily. Thus, the combination of freeze-dried with steaming or blanching pretreatment could be proposed as a sustainable strategy to improve the quality of lily bulbs for industrial application.

A self-rotating, single-actuated UAV with extended sensor field of view for autonomous navigation.

Uncrewed aerial vehicles (UAVs) rely heavily on visual sensors to perceive obstacles and explore environments. Current UAVs are limited in both perception capability and task efficiency because of a small sensor field of view (FoV). One solution could be to leverage self-rotation in UAVs to extend the sensor FoV without consuming extra power. This natural mechanism, induced by the counter-torque of the UAV motor, has rarely been exploited by existing autonomous UAVs because of the difficulties in design and control due to highly coupled and nonlinear dynamics and the challenges in navigation brought by the high-rate self-rotation. Here, we present powered-flying ultra-underactuated LiDAR (light detection and ranging) sensing aerial robot (PULSAR), an agile and self-rotating UAV whose three-dimensional position is fully controlled by actuating only one motor to obtain the required thrust and moment. The use of a single actuator effectively reduces the energy loss in powered flights. Consequently, PULSAR consumes 26.7% less power than the benchmarked quadrotor with the same total propeller disk area and avionic payloads while retaining a good level of agility. Augmented by an onboard LiDAR sensor, PULSAR can perform autonomous navigation in unknown environments and detect both static and dynamic obstacles in panoramic views without any external instruments. We report the experiments of PULSAR in environment exploration and multidirectional dynamic obstacle avoidance with the extended FoV via self-rotation, which could lead to increased perception capability, task efficiency, and flight safety.

Effect of Microwave Treatments Combined with Hot-Air Drying on Phytochemical Profiles and Antioxidant Activities in Lily Bulbs (Lilium lancifolium).

Lily bulbs (Lilium lancifolium Thunb.) are rich in phytochemicals and have many potential biological activities which could be deep-processed for food or medicine purposes. This study investigated the effects of microwaves combined with hot-air drying on phytochemical profiles and antioxidant activities in lily bulbs. The results showed that six characteristic phytochemicals were identified in lily bulbs. They also showed that with an increase in microwave power and treatment time, regaloside A, regaloside B, regaloside E, and chlorogenic acid increased dramatically in lily bulbs. The 900 W (2 min) and the 500 W (5 min) groups could significantly suppress the browning of lily bulbs, with total color difference values of 28.97 ± 4.05 and 28.58 ± 3.31, respectively, and increase the content of detected phytochemicals. The highest oxygen radical absorbance activity was found in the 500 W, 5 min group, a 1.6-fold increase as compared with the control (57.16 ± 1.07 µmol TE/g DW), which was significantly relevant to the group's phytochemical composition. Microwaves enhanced the phytochemicals and antioxidant capacity of lily bulbs, which could be an efficient and environmentally friendly strategy for improving the nutrition quality of lily bulbs during dehydration processing.

[Raman spectroscopy analysis of carbon structural evolution of diesel particulate matters with the treatment of nonthermal plasma].

Original and nonthermal plasma treated particulate matters (PM) samples of a diesel were obtained and characterized by Raman spectroscopy. A five-bands model was adopted for Raman spectrum curve fitting. As parameters involving most information about carbon structure, variation of FWHM of D1 band and D3 relative intensity were analyzed. It was found that original PM presented higher graphical structural order and lower chemical heterogeneity with the increase in the diesel load. After the treatment of NTP, the graphical structural order and chemical heterogeneity of PM kept at a relative stable level, affected very slightly by diesel load. Meanwhile, the amount of molecular carbon in PM increased. Further study for relation between structural evolution and chemical reactivity of PM with chemical kinetics would make Raman spectroscopy of great promise to become an important method for PM characterization, which could provide basis for more effective removal.

Effect of temperature control conditions on DPF regeneration by nonthermal plasma.

A regeneration test of a diesel particulate filter (DPF) was conducted under different temperature conditions with air as the gas source and a nonthermal plasma (NTP) injection system. We investigated the influence of the ambient temperature on the DPF regeneration performance and the oxidative decomposition amount of particulate matter (PM) and analyzed the changes in the PM oxidation characteristics by thermogravimetric analysis (TGA). The higher the temperature, the lower the decomposition amount of PM was under constant temperature conditions. The decomposition amount of PM was the highest at 80 °C (3.74 g), and the PM at interface P2 was not completely removed. The volume concentrations of the DPF regeneration products (CO and CO2) were higher under variable than constant temperature conditions. In addition, the peak temperature of interface P1 occurred 10-30 min earlier, complete regeneration occurred at interface P2, and DPF regeneration occurred faster than under temperature conditions. The initial temperature of the control device was 110 °C, and the maximum mass of PM oxidation decomposition was 4.26 g after regeneration for 15 min cooling to 80 °C. The main form of elemental carbon (EC) transformed into the low ignition point component and the oxidation activity was improved after NTP injection.

Catalytic conversion of rape straw into biofuels by direct non-thermal plasma modified HZSM-5.

Fresh HZSM-5 catalyst modification experiment was carried out on the direct non-thermal plasma (DNTP) reactor. The aim of this work was to study the effects of modified voltages on the physicochemical properties of HZSM-5 and its enhancement in biomass catalytic pyrolysis. The results showed that DNTP modification was performed at different voltages of 20 kV, 22 kV, 24 kV, compared with fresh HZSM-5, the effect of 22 kV voltage was preferably. H-22 had the largest specific surface area and mesoporous volume, and the total acid content added 17.02%. The biomass catalytic pyrolysis test was used to test the HZSM-5 catalytic activity after modification. The results showed that the catalyst obtained by the catalyst under 22 kV modified voltage had the highest monocyclic aromatic hydrocarbon selectivity of 40.55%.

Well-controlled gestational diabetes mellitus without pharmacologic therapy decelerates weight gain in infancy.

Aim: There are no prospective longitudinal studies on the association between well-controlled gestational diabetes mellitus (GDM) without pharmacologic therapy and the physical growth of offspring in infancy. We aimed to identify the trajectories in physical growth (from 0-12 months of age) in the offspring of mothers with well-controlled GDM without pharmacologic therapy in a prospective cohort in China. Methods: This study included 236 offspring of mothers with GDM and 369 offspring of mothers without GDM. Mothers with GDM were not on pharmacologic therapy. The length and weight of infants were measured at 0, 1, 3, 6, and 12 months. Linear mixed-effect models and linear mixed-effect models were applied. Results: The fully adjusted model showed that the weight-for-age z-score (WAZ), length-for-age z-score (LAZ), and BMI-for-age z-score (BMIZ) were similar at birth for the GDM and control groups. However, subsequent increases in WAZ and BMIZ for the GDM group lagged the increases for the control group at the subsequent periods of observation, 0-1, 0-6, and 0-12 months. Conclusions: Well-controlled GDM without pharmacologic therapy may normalize physical growth of offspring at birth and decelerate their weight gain in infancy. Whether glycemic control can mitigate the long-term effects of GDM on the growth trajectory in offspring remains unclear.

Associations between gestational diabetes mellitus and the neurodevelopment of offspring from 1 month to 72 months: study protocol for a cohort study.

INTRODUCTION: Gestational diabetes mellitus (GDM) is a common gestational disease and an important global public health problem. GDM may affect the short-term and long-term health of offspring, but the associations between GDM and the neurodevelopment of offspring of mothers with GDM (OGDM) are still unclear, and studies based on the Chinese population are lacking. We aim to determine the associations between GDM and the neurodevelopment of OGDM by studying a cohort of OGDM and offspring of non-GDM mothers. METHODS AND ANALYSIS: The single-centre prospective cohort study is being conducted in China over 7 years. A total of 490 OGDM (GDM group) and 490 fromof healthy mothers (control group) will be enrolled during the same period. Baseline characteristics, neuropsychological development scores and clinical data at specific time points (at 0, 1, 3, 6, 12, 24, 36, 48, 60 and 72 months old) will be collected from the children in both groups until the age of 6 years. The associations between GDM and the neurodevelopment of OGDM from infancy to preschool age will be analysed using a multiple linear regression model adjusted for confounders. In addition, we will compare longitudinal data to further assess the effects of GDM on neurodevelopmental trajectories. ETHICS AND DISSEMINATION: The study has been approved by the Ethics Committee of the Children's Hospital of Chongqing Medical University (Approval Number: (2019) Institutional Review Board (IRB) (STUDY) No. 85). The findings of this study will be disseminated through open access journals, peer-reviewed journals and scientific meetings. TRIAL REGISTRATION NUMBER: NCT03997396.

Fatty-acid receptor CD36 functions as a hydrogen sulfide-targeted receptor with its Cys333-Cys272 disulfide bond serving as a specific molecular switch to accelerate gastric cancer metastasis.

BACKGROUND: Hydrogen Sulfide (H2S), a third member of gasotransmitter family along with nitric oxide (NO) and carbon monoxide (CO), exerts a wide range of cellular and molecular actions in our body. There is a large body of evidence suggesting that H2S plays an important role in cancer metastasis; however, the molecular mechanisms of H2S-mediated acceleration of cancer metastasis remain unknown. METHODS: We examined the promote effects of H2S on phenotype of gastric cancer (GC) cells (including those of express wild type CD36 and mutant CD36) in vitro and in vivo. GC patients' samples were used for clinical translational significance evaluation. FINDINGS: H2S triggered lipid metabolism reprogramming by significantly up-regulating the expression of the fatty-acid receptor CD36 (CD36) and directly activating CD36 in GC cells. Mechanistically, a disulfide bond located between cysteine (Cys)333 and Cys272 within the CD36 protein structure that was labile to H2S-mediated modification. The long chain-fatty acid (LC-FA) binding pocket was capped by a turn in the CD36 protein, located between helical and sheet structures that were stabilized by the Cys333-Cys272. This limited the secondary binding between LC-FAs and lysine (Lys)334. Breaking the Cys333-Cys272 disulfide bond restored the second LC-FA binding conformation of CD36. Targeting CD36 in vivo blocked H2S-promoted metastasis and improved animal survival. INTERPRETATION: These findings identify that the Cys333-Cys272 disulfide bond disrupted the integrity of the second LC-FA binding conformation of CD36. Therefore, CD36 can directly activate LC-FA access to the cytoplasm by acting as a direct target molecule for H2S.

Catalytic upgrading of pyrolysis vapor from rape straw in a vacuum pyrolysis system over La/HZSM-5 with hierarchical structure.

Catalytic upgrading of pyrolysis vapor from rape straw was performed in a vacuum pyrolysis system over La/HZSM-5 with hierarchical structure. When 3M Na2CO3 was used for alkali treatment, the desilication process of HZSM-5 zeolite was highly controllable and the hierarchical porous HZSM-5(Hi-ZSM-5) zeolite was formed. After that, Hi-ZSM-5 was modified by impregnation with lanthanum ion, the acid sites of Lewis increased and the concentrations ratio of Brönsted acid and Lewis acid of the catalyst was improved. The highest hydrocarbons selectivity (49.86%), the lowest carbonyl compounds content (11.06%), and reasonable catalytic stability were obtained by the La/Hi-ZSM-5 catalyst. In addition, La/Hi-ZSM-5 further reduced the coke content of the catalyst to 11.05%, while increasing the selectivity of high value aromatic hydrocarbons. Obviously, La/Hi-ZSM-5 zeolite had high catalytic activity, and exhibited good potential and a beneficial nature for efficient preparation of high-valued bio-oil from rape straw.