Search

Background: Although the human adenovirus infection is common, adenovirus infection with liver dysfunction is rare. Methods: To retrospectively analyze and compare the clinical characteristics and outcomes of pediatric patients diagnosed with severe adenovirus pneumonia with and without liver dysfunction, who were admitted to the pediatric intensive care unit of Hunan Children’s Hospital (South China University) between January 2018 and June 2022. Results: Of the 330 severe adenovirus pneumonia cases analyzed (mean age, 19.88 ± 18.26 months), 102 were girls and 228 were boys. They were divided into two groups: those with liver dysfunction (n = 54) and without liver dysfunction (n = 276). Comparison analysis showed no significant between-group differences in body mass index and levels of white blood cells, neutrophils, platelets, albumin, total bilirubin, direct bilirubin, indirect bilirubin, creatine kinase, procalcitonin, creatinine, and urea nitrogen. However, the levels of alanine aminotransferase (175.99 U/L vs 30.55 U/L) and aspartate transaminase (215.96 U/L vs 74.30 U/L) were significantly higher in patients with liver dysfunction compared to those without liver dysfunction. Further analysis showed that pediatric patients with liver dysfunction had a significantly lower percentage of natural killer (NK) cells (6.93% vs 8.71%) and higher mortality rate (22% vs 9%) than those without liver dysfunction. Conclusion: A decrease in serum NK cell levels in pediatric patients with severe adenovirus pneumonia could serve as a marker for monitoring the onset or progression of hepatic damage.

Three-dimensional free bending is a new tube forming technology with continuous variable curvature. In order to improve the forming quality of tube, this paper studies the principle of three-dimensional free forming system and the numerical calculation of bending moment in detail, and it uses the finite element simulation to model the mechanism in the bending process. The simulation model is used to simulate the forming process of copper tube, and the influence of key process parameters on the forming process is analyzed,the shape of the inner cavity of the bending die and the gap between the tube and the bending die are studied, the distance between the bending die and the guide column is studied, the axial feed rate on the forming quality of tubular bending parts has also been studied. The optimum process parameters were determined by finite element simulation and analysis.

Background. Sepsis can lead to multiple organ damage, of which the heart is one of the most vulnerable organs. Vagal nerve stimulation can reduce myocardial injury in sepsis and improve survival rates. However, the potential impact of low-level tragus stimulation and disparate cell populations on sepsis-induced myocardial dysfunction remains undetermined. Methods. A cardiac single-cell transcriptomic approach was used for characterizing cardiac cell populations that form the heart. Single-cell mRNA sequencing data were used for selecting all cardiac macrophages from CD45+ cells. Then, echocardiography, western blot, flow cytometry, immunofluorescence, and immunohistochemistry were performed to verify the single-cell mRNA sequencing results. Results. Using single-cell mRNA sequencing data, we uncovered the multiple cell populations contributing to myocardial injury in sepsis under low-level tragus stimulation, thereby illustrating a comprehensive map of the cardiac cellular landscape. Pseudotiming analysis in single-cell sequencing showed that low-level vagal nerve stimulation played an anti-inflammatory role by promoting cardiac monocytes into M2 macrophages, which significantly increased α7nAChR expression in heart tissues. Echocardiography assessment indicated that low-level vagal nerve stimulation could also improve cardiac functions in mice with sepsis-induced myocardial dysfunction. In addition, the heart tissues of mice from the sepsis group with low-level tragus stimulation had significantly lower interleukin-1β expression levels than those from the sepsis group. Flow cytometry analysis showed that different acetylcholine concentrations promoted cardiac monocytes into M2 macrophages in in vitro experiments. Conclusion. Low-level tragus stimulation could improve sepsis-induced myocardial dysfunction by promoting cardiac monocytes to M2 macrophages.

The processing quality of steel bar thread has a large influence on its performance. Using the traditional thread processing technology, it is difficult to meet the requirements of steel bar thread processing with large diameter and high strength. A technical process for HRB500 high-strength steel bar thread processing, including face milling, rib stripping, chamfering, necking formation, and thread rolling, was proposed. The influences of cutting parameters on the cutting force of steel bar surface in face milling were analyzed by the finite element method. For the necking formation process, the effect of springback amount on necking formation was studied. The main parameters in rolling formation were analyzed and calculated, including extrusion pressure, rolling speed, and rolling feed. Experiments for uniaxial tensile of the processed high-strength steel bar threads were carried out. The results showed that cutting depth has the largest influence on the cutting force; the second is feed rate. The effect of the spindle speed was lowest during the face milling. After the necking formation process, the values of the maximum springback amount along the X, Y, and Z directions were 0.05 mm, 0.06 mm, and 0.98 mm, respectively. The finished thread met the precision and quality requirements of a grade I joint. This study provides a high-quality processing technology for large-diameter and high-strength steel bar threads.

Organogels are excellent drug carrier for controlled release. Organogels based on amino acid derivatives has been widely used in the area of drug delivery. In this study, a series of the organogel system based on amino acid derivatives gelators was designed and prepared to investigate the structure-property correlation in organogels. To investigate the factors that influence the property of drug release, we varied the formulation in the organogels: gelator structure, gelator concentration, volume of antigelation solvent, and drug loading. Through the Box–Behnken tests, the optimum organogel formulation in vitro was obtained. The self-healing properties of the organogel have been utilised for injection of a model lipophilic risperidone in situ, and sustained release of the drug has been studied over about one week in vivo. In conclusion, the gelation ability of gelators could be adjusted by the gelator structure. Gel property is related with the whole composition of the formulation. As drug carrier, the drug release property of organogels is affected by multiple factors. Our investigation of the gel release property will play a theoretical guiding role in the application in the in situ drug delivery system.

Sepsis is a life-threatening organ dysfunction caused by the disorder of the body's response to infection, and is one of the main causes of death in critically ill patients. Ferroptosis is a kind of iron dependent cell death, characterized by intracellular reactive oxygen species (ROS) accumulation. Sepsis can cause a substantial accumulation of ROS in cells. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a key regulator of antioxidant and plays a critical protective role in sepsis induced ferroptosis by regulating the expression of proteins related to the ferroptosis pathway. Current studies have found that activation of Nrf2 has a protective effect on ferroptosis induced by sepsis. In this paper, we summarized the regulation mechanism of Nrf2 in ferroptosis, in order to provide references for the treatment of sepsis.

The train communication Ethernet (TCE) of modern intelligent trains is under an ever-increasing threat of serious network attacks. Denial of service (DoS) and man in the middle (MITM), the two most destructive attacks against TCE, are difficult to detect by conventional methods. Aiming at their highly time-correlated properties, a novel dynamic temporal convolutional network-based intrusion detection system (DyTCN-IDS) is proposed in this paper to detect these temporal attacks. A semiphysical TCE testbed that is capable of simulating real situations in TCE-based trains is first built to generate an effective dataset for training and testing. DyTCN-IDS consists of two phases, and in the first phase, systematic feature engineering is designed to optimize the dataset. In the second phase, a basic detection model that is good at dealing with temporal features is first built by utilizing the temporal convolutional network with several architectural optimizations. Then, in order to decrease the computational consumption waste on network packet sequences with different lengths of inner temporal relationships, dynamic neural network technology is further adopted to optimize the basic detection model. Diverse experiments were carried out to evaluate the proposed system from different angles. The experimental results indicate that our system is easy to train, converges fast, costs less computational resources, and achieves satisfying detection performance with a macro false alarm rate of 0.09%, a macro F-score of 99.39%, and an accuracy of 99.40%. Compared to some canonical DL-based IDS and some latest IDS, our system acquires the best overall detection performance as well.

Background The coronavirus disease 2019 (COVID-19) pandemic brought remarkable disruption to the ways in which healthcare was delivered. This study aimed to examine changes in pediatric healthcare utilization in Hunan Province, China, during the COVID-19 pandemic. Methods An electronic survey was conducted among 142 hospitals in Hunan Province, China. Using data from January 1 to April 30, 2019 as a reference, the changes in the number of visits for different types of pediatric healthcare between January 1 and April 30, 2020 were calculated. Changes in the number of admissions for infections and injuries were also evaluated. Results The total number of pediatric healthcare presentations decreased by 53.3% in the first four months of 2020. The most remarkable reductions were observed in the utilization of emergency room (ranging from -45.7% to -94.9% among three hospital levels) and observation room (-55.8% to -77.7%); neonatal inpatient care experienced the smallest decreases (-21.2% to -25.5%). Approximately 85% of the total reduction in the number of pediatric inpatient admissions was attributable to the reduction in admissions for infections. A 13.3% increase in the number of admissions for injuries was observed among third-level hospitals. Conclusions The utilization of all types of pediatric healthcare services in Hunan Province declined markedly after the outbreak of COVID-19. The reasons, consequences, and responses to these changes should be addressed in future studies and actions.

OBJECTIVES Pancreatic injury is multifactorial and potentially devastating for critically ill children. We aimed to evaluate whether serum amylase and lipase among critically ill children could serve as an independent biomarker to predict pancreatic injury. DESIGN Retrospective cohort. SETTING PICU of a tertiary, pediatric medical center. PATIENTS Seventy-nine autopsies. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS A group of 79 children who died of different causes were investigated by autopsy. They were divided into pancreatic injury group and pancreatic noninjury group according to autopsy findings. Data based on patients' demographics, vital signs, laboratory findings, and clinical features at admission were collected and compared. Logistic regression was used to identify predictive factors for pancreatic injury. Receiver operating characteristic curve was constructed for assessing serum amylase and serum lipase to predicting pancreatic injury. Forty-one patients (51.9%) exhibited the pathologic changes of pancreatic injury. The levels of lactate, erythrocyte sedimentation rate, alanine transaminase, aspartate transaminase, and troponin-I in the injury group were significantly higher than that in the noninjury group, whereas the level of calcium was significantly lower than that in the noninjury group (p < 0.05). Multivariable logistic regression analysis showed that serum amylase, serum lipase, and septic shock were significantly associated with the occurrence rate of pancreatic injury. The statistically significant area under the curve results were as follows: serum amylase: area under the curve = 0.731, at a cutoff value of 97.5, sensitivity = 53.7, and specificity = 81.6; and serum lipase: area under the curve = 0.727, at a cutoff value of 61.1, sensitivity = 36.6, and specificity = 92.1. CONCLUSIONS Serum amylase and lipase could serve as independent biomarkers to predict pancreatic injury in critically ill children.

Patients with hemophagocytic lymphohistiocytosis (HLH) have high risk of early mortality. The purpose of this study was to test the hypothesis that the elevated level of serum myoglobin among patients with HLH is associated with disease severity and increased risk of mortality. We retrospectively investigated the serum myoglobin levels from 155 pediatric patients diagnosed with HLH in the Hunan Children's Hospital, China. The levels of myoglobin and creatine kinase at hospital admission among non-survivors and survivors were compared. The myoglobin level was dichotomized for the estimation of hazard ratio (HR) for mortality. Patients who died within 7 and 30 days of hospitalization had significantly higher myoglobin levels than did survivors (p 0.05). The myoglobin level was negatively associated with the days of survival among non-survivors (Spearman correlation coefficient = - 0.29, p = 0.04). An elevated myoglobin level ( 90 ng/mL) was significantly associated with increased mortality (unadjusted HR = 2.66, 95%CI: 1.41, 5.00, p = 0.0024) and persisted after adjusting for age, Epstein-Barr virus infection, admission department, acute kidney injury, myocardial damage, and shock. In conclusion, an elevated serum myoglobin level was associated with increased risk of early death among pediatric patients with HLH, suggesting the potential of myoglobin to be used as a reference indicator for monitoring and managing of HLH.

Purpose Our aim was to investigate the age-associated plasma protein profiles in pneumonia-derived sepsis between infants and toddlers and identify potential age-adapted prognostic markers for poor outcome of pneumonia-derived pediatric sepsis. Experimental design A nested case-control study strategy was applied. The plasma proteomes of pneumonia-derived pediatric septic patients with different outcomes between infants and toddlers were respectivly analysed compared to their age-matched controls. Results Compared to toddlers, pneumonia-derived sepsis in infants was characterized by increased upregulation of protein processing in the ER, proteasome and antigen processing and presentation; and reduced downregulation in complement and coagulation cascades and cholesterol metabolism. Among them, the pentose phosphate pathway as well as the complement and coagulation cascades were possibly associated with poor outcome of pneumonia-derived sepsis. Furthermore, we confirmed that HP, THBS1, and SAA1/2 were potential prognostic markers for poor outcome of pneumonia-derived sepsis in infant patient groups. Conclusions and clinical relevance Age-associated plasma protein profiles of pneumonia-derived pediatric septic patients provided potential age-adapted biomarkers for a more precise prognosis of poor outcome in pneumonia-derived pediatric sepsis and helped to improve the survival of septic children. This article is protected by copyright. All rights reserved.

Background Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder. How to stratify high risk patients is one of the current challenges for the treatment of HLH. HLH patients usually fulfill multiple but not all eight diagnostic criteria. Different combinations of the fulfilled criteria may naturally cluster into previously undescribed subsets or phenotypes that may have different pathophysiology and demonstrate different risks for a poor outcome. The objectives of this study were to identify HLH subgroups according to the fulfillment of diagnostic criteria and evaluate the risk of multiple organ dysfunction syndrome (MODS) and 30-day mortality for subgroups. We retrospectively collect medical records of patients with discharge diagnosis of HLH between June 2015 and October 2018 from a tertiary children’s hospital in China. Latent class analysis was used to identify class defining variables from HLH diagnostic items, and subgroups were defined according to different combinations of the class defining variables. Results Triglyceride and fibrinogen were identified as the class defining variables. When evaluated in combinations, patients with hypertriglyceridemia and normal fibrinogen levels during hospitalization had the lowest risks for MODS (27.8%, OR = 1) and 30-day mortality (18.8%, OR = 1), and patients with normal triglyceride and hypofibrinogenemia had the highest risks for MODS (86.2%, OR = 16.24, P = 0.0002) and 30-day mortality (57.1%, OR = 5.78, P = 0.0187). The fulfillment status of hypertriglyceridemia and hypofibrinogenemia within 72 h of hospital admission was also associated with the risk of adverse outcomes. Conclusions The fulfillment status of hypertriglyceridemia and hypofibrinogenemia were associated with the risks of MODS and 30-day mortality among pediatric HLH patients. Further studies are needed to validate this association and investigate its clinical utility in the severity evaluation for HLH.

This study focuses on the radiation noise of ceramic angular contact ball bearings for motorised spindles. The differential equations of the vibrations for each bearing component are established, and the characteristics of various sound sources are analysed. Then, a multi-sound source method for calculating the radiation noise of a ceramic angular contact ball bearing is developed. The accuracy and validity of the proposed method are verified through numerical calculations and a corresponding experiment. Subsequently, the frequency spectrum characteristics of the radiation noise of the bearing components are discussed in detail according to the multi-sound source method. The radiation noise of each bearing component varies nonlinearly with the rotation speed, and the variation is consistent with the total radiation noise of the bearing. The eigenfrequency noise of each component appears clearly in the noise frequency spectrum. The results show that the proposed method can well predict the radiation noise of a ceramic angular contact ball bearing and provide a theoretical reference for the study of silent ceramic angular contact ball bearings for motorised spindles.

Coalescence of conducting droplets dispersed in an immiscible medium can be facilitated by an electric field. However, droplets recoil promptly after contact in sufficiently high electric fields if the cone angle between droplets exceeds a critical value. To elucidate the critical condition for droplet coalescence, the behavior of two suspended droplets after contact with a direct current electric field is studied. It is shown that the critical angle is determined not only by the droplet geometry but also conductivity, surfactant concentration, and size. As the droplet conductivity increases, more identical ions accumulate on the adjacent interfaces of two droplets due to the faster ionic migration, which results in Coulombic repulsion between droplets and a reduced critical angle. For surfactant-laden droplets, film drainage induces a surfactant concentration gradient on the leading edges of droplets, and then Marangoni stress is formed to reduce the critical angle. In the case of large droplets, the bri...

In recent decades, the additive manufacturing technology has made great progress in software and methods in various fields, and gradually explored in a deeper and broader manner. It has changed from the mature homogenized lattice type and model design to a non-uniform direction. It has also started to improve from the aspects of material innovation, additive manufacturing printing technology, etc., to change the additive manufacturing technology and control parameters in the manufacturing process, Furthermore, the model or part can be improved to have better mechanical properties, such as stiffness, strength and wear resistance, which provides an important research methodology for the better development of this direction. These aspects include the software used, the type of structural analysis, the software used and verification, as well as the methods applied in the study of variable density lattices and the application and verification of improved research methods. In addition, there are density design optimization, variable density lattice design and lattice geometric characteristics’ design in geometric topology optimization design. The expected design of the model or part at the design level has reached the ideal model or part, which provides both a framework and ideas for the future research direction of non-uniform lattice design and a broader field of application, and will promote the future research and development prospects of variable density lattices.

Engineering ceramic has been widely used in various fields, especially in bearings, for its excellent characteristics, such as the outstanding tolerance to temperature and wear, good stiffness, high strength, and so on. Surface quality is vital for precision bearings. However, the machining of ceramic materials is difficult due to their high hardness and high brittleness. To investigate the effect of grinding parameters (grinding wheel speed, workpiece, and grinding depth) on the surface quality in internal grinding of Silicon Nitride (Si3N4) ceramics applied to bearing ring, an orthogonal experiment was carried out in this study. The surface roughness (SR), surface morphology, and subsurface damage of the ceramic material were analyzed based on a sequence of experimental results, respectively. Then, two prediction models on the SR in the internal grinding of Si3N4 ceramics were established combining the experimental results, internal grinding process, and empirical equation. This study provides a significant reference to obtain better surface quality in the internal grinding of ceramic material.

The difficulties and challenges of applying the HLH-2004 diagnostic criteria to early identification and diagnosis of haemophagocytic lymphohistiocytosis have been fully addressed in previous studies. However, the distribution of the diagnostic time lag of haemophagocytic lymphohistiocytosis and related patient characteristics remain unclear. This study investigated the time lags between symptom onset and diagnosis and between hospital admission and diagnosis among pediatric patients with haemophagocytic lymphohistiocytosis, and identified factors that associated with a shorter or longer diagnostic time lag. The cohort of patients with haemophagocytic lymphohistiocytosis was drawn from a tertiary children's hospital and consisted of 122 pediatric patients. The distributions of symptom-to-diagnosis and admission-to-diagnosis time lags were assessed. Clinical characteristics within 48 h of admission and the fulfillment of HLH-2004 diagnostic criteria were compared among admission-to-diagnosis time lag categories. Logistic regression analyses were conducted to identify factors associated with an admission-to-diagnosis time lag >3 days. The median interval from first symptom onset to HLH diagnosis was 12 days (range 4–71 days) and the median interval from hospital admission to HLH diagnosis was 2 days (range 0–23 days). The following factors were negatively associated with admission-to-diagnosis > 3 days: Epstein–Barr virus infection; admission through pediatric intensive care unit; diagnosis established without NK-cell activity and soluble CD25 tests; the performance of all readily available diagnostic tests for HLH (within 48 and 72 h); concurrent fever, splenomegaly, and cytopenias within 48 h; hemophagocytosis, hypertriglyceridemia and/or hypofibrinogenemia within 48 h; and elevated ferritin, total bilirubin, alanine aminotransferase, and prothrombin time within 48 h. Our findings suggest that performance of adequate diagnostic tests for HLH is essential for early diagnosis of HLH. Once suspected, immediate and adequate diagnostic tests for HLH should be arranged for PICU patients. Improvements in diagnostic procedures and monitoring plans are needed to promote early diagnosis of HLH.

Image processing technologies are available for high-throughput acquisition and analysis of phenotypes for crop populations, which is of great significance for crop growth monitoring, evaluation of seedling condition, and cultivation management. However, existing methods rely on empirical segmentation thresholds, thus can have insufficient accuracy of extracted phenotypes. Taking maize as an example crop, we propose a phenotype extraction approach from top-view images at the seedling stage. An end-to-end segmentation network, named PlantU-net, which uses a small amount of training data, was explored to realize automatic segmentation of top-view images of a maize population at the seedling stage. Morphological and color related phenotypes were automatic extracted, including maize shoot coverage, circumscribed radius, aspect ratio, and plant azimuth plane angle. The results show that the approach can segment the shoots at the seedling stage from top-view images, obtained either from the UAV or ground high-throughput phenotyping platform. The average segmentation accuracy, recall rate, and F1 score are 0.96, 0.98, and 0.97, respectively. The extracted phenotypes, including maize shoot coverage, circumscribed radius, aspect ratio, and plant azimuth plane angle, are highly correlated with manual measurements (R2=0.96-0.99). This approach requires less training data and thus has better expansibility. It provides practical means for high-throughput phenotyping analysis of early growth stage crop populations.

This paper focuses on the distribution characteristics of the radiation noise for a full-ceramic angular contact ball bearing (FCACBB). A model for calculating the radiation noise of a FCACBB was established based on the bearing dynamic characteristics and sound radiation theory, and the effectiveness and accuracy of the method were verified by corresponding experiments. The variation of the radiation noise for a FCACBB with the rotational speed was analyzed. The directivity of the sound field in the circumferential direction was found. The variation trends of the radiation noise in the friction load zone and the impact load zone were discussed. The attenuation of the radiation noise in the radial direction and in the axial direction was investigated. The directivity angle and the degree of directivity of the sound field were explored at different radial and axial distances. The results show that the inhomogeneous contacts between the bearing components in the circumferential direction result in different degrees of friction and impact vibration at different locations, which makes the radiation noise of the FCACBB have a larger component in the radial direction than in the axial direction. The conclusions can provide a reference for predicting the radiation noise of FCACBBs and further optimizing the sound field.

Recent studies have reported that the imbalance of T helper 1 cell (Th1), Th17 and regulatory T cell (Treg) have been confirmed to play a vital role in the development of sepsis and other inflammatory diseases. Baicalin (BA) has anti-inflammatory properties and improves survival in sepsis. We investigated whether baicalin could regulate Th1, Th17 and Treg responses to ameliorate sepsis-associated pancreatic injury through the ras homolog family member A (RhoA)-Rho kinase (ROCK) pathway. The sepsis model was established by using the cecal ligation and puncture (CLP) method. Fifty mice were randomly divided into five groups (n = 10): sham group, model group, low-dose group (BA-L, 100 mg/kg of baicalin), medium-dose group (BA-M, 200 mg/kg of baicalin) and highdose group (BA-H, 300 mg/kg of baicalin). The effects of baicalin on the pancreatic injury, on changes of Th1, Th17 and Treg cells in vivo and in vitro, on RhoA, ROCK1 and signal transducer and activator of transcription (STAT) signaling pathways, and on levels of interferon-γ (IFN-γ), interleukin-17 (IL-17) and IL-10 were examined. Treatment of the CLP mice with baicalin significantly reduced the extent, scope and severity of the pathological changes of sepsis-associated pancreatic injury. Baicalin evidently reduced Th1 and Th17 cells and increased Treg cells in peripheral blood, spleen, pancreatic tissue and significantly inhibited T-box protein expressed in T cells (T-bet), retinoic acid receptor-related orphan receptor γt (RORγt) and increased forkhead/winged helix transcription factor (Foxp3) expressions in the pancreatic tissue. Baicalin reduced the expressions of RhoA, ROCK1, phosphorylated STAT4 (p-STAT4), p-STAT3 and increased the expression of p-STAT5 in peripheral blood, spleen and pancreatic tissue. Baicalin reduced the expressions of IFN-γ and IL-17 and increased the IL-10 in serum and pancreatic tissue. Baicalin is capable of ameliorating sepsis-associated pancreatic injury and regulating Th1, Th17 and Treg responses in sepsis. The present study provided a potential adjunctive therapy for treating pancreatic injury in sepsis, and further study is needed to reveal its deeper mechanisms.

Additional file 1 Supplementary Table 1. Pathogens detected from 160 pediatric HLH patients according to survival groups. Supplementary Table 2. Pathogens detected from 86 pediatric HLH patients with infection-confirmed sepsis.

Ceramic angular contact ball bearing is widely used in a high-speed motorised spindle because of their excellent properties such as wear resistance, high temperature resistance, and corrosion resistance. In this study, the characteristics and influencing factors of the radiation noise for a full ceramic angular contact ball bearing applied in the motorised spindle are investigated. Based on a single factor test method, the variations of bearing noise with preload, oil supply, and rotation speed were investigated, and then, the optimal preload and oil supply under the specific speed were obtained. The sound field directivity in the circumferential distribution of the bearing noise was discussed, and the reasons for the uneven distribution of the sound field were elucidated. According to the experimental results, a prediction model on the radiation noise of a full ceramic angular contact ball bearing under certain conditions was proposed. The conclusions will provide a reference for reducing the radiation noise of full ceramic angular contact ball bearings in high-speed operation and improving the bearing performance.

The electrocoalescence behavior of surfactant-laden droplet pairs in oil under a DC electric field was investigated in this paper. The characteristic parameters such as coalescence time, liquid bridge diameter and contact angle were analyzed for varying surfactant concentrations and electric capillary numbers. The results show that the horizontal electrocoalescence of two identical droplets with the same physical properties is symmetrical. Moreover, the surfactant has a significant influence on the pressure difference at the liquid bridge, which results in a variation of the liquid bridge growth and coalescence time. The pressure difference between the droplet and the liquid bridge is significantly dependent on the initial contact angle, which is determined by the electric capillary number Ca and surfactant concentration. The theoretical analysis and experimental results show that the large initial contact angle restrains the growth of the liquid bridge in the initial coalescence stage. Considering the effect of the initial contact angle, a characteristic time is proposed to describe the evolution of the liquid bridge.

The current understanding and developments of phase separation technology based on ultrasonic standing waves (USWs) are reviewed. Most previous reviews have focused on microscale applications of this technology in the fields of biological materials and food processing. This review covers different applications of ultrasonic separation technology, especially in petrochemical industry. The kinetic mechanism of ultrasonic, design of reactors, separation principles, and related applications are discussed in detail. We lay special stress on the motion characteristics of particles in USWs. According to the particle numbers, particle properties, and frequency characteristics, the separation principles are reasonably categorized as: (1) Bands effect; (2) Acoustophoretic coefficient; (3) Particle density; (4) Sweep frequency. Diverse separation principles improve the universality of ultrasonic separation technology. However, acoustic streaming and acoustic cavitation are two of the main challenges in the application of ultrasonic separation. Based on the current research, the future research can focus on the following aspects: (1) Explore the mechanism of ultrasonic demulsification; (2) Establish unified evaluation criteria for acoustic separation systems; (3) Develop the basis for determination of acoustic cavitation and non-cavitation.

In this study, the electrocoalescence characteristic of two drops with different surfactant concentrations suspended in oil is revealed. Different from the symmetrical coalescence of identical drops, the asymmetrical liquid bridge is induced by the capillary force, which involves the interfacial tension gradient between the drops. In addition, a mushroom-like jet is formed during asymmetrical coalescence, causing mixing of drops. A characteristic time considering the interfacial tension gradient is proposed to describe the asymmetrical liquid bridge evolution. The mushroom-like jet is found to be driven by the pressure difference between drops, which has a positive correlation with the interfacial tension gradient. Moreover, it is found that the electrocoalescence time is shortened as the interfacial tension increases. This study indicates that increasing the interfacial tension gradient will enhance the jet flow rate and reduce the coalescence time, which is of significance to improve the mixing efficien...

The alkali-surfactant-polymer (ASP) flooding as one of efficient enhanced oil recovery technology has attracted great interest in the recent years. Nevertheless, the high stability of the oily water has become a threat to the environmental security. And most of the separation methods have been gained through trial-and-error approaches at present. However, there is a lack of clear microscopic scale study with respect to the mechanisms that govern the separation efficiency. In this paper, the effects of alkali (A), surfactant (S) and polymer (P) on the coalescence behavior of oil droplets are experimentally investigated with high-speed photography. The results indicate that the composition of the ASP flooding solution substantially influences the coalescence patterns of oil droplets. The optimum solute concentration of each component in ASP for oil droplet coalescence is obtained based on the microscopic experimental results. Statistical investigation on contact angles of the coalesced oil droplets is concluded that effective contact angles are distributed asymmetrically within the ranges of conditions studied. And most of the oil droplets are found to coalesce at small contact angles (5–25°) or large contact angles (50–80°). The research findings are of great significance for developing high-efficient processing technology for ASP flooding produced water.

The breakup behaviors of aqueous droplets with surfactant in oil under direct current (DC) electric field are investigated in this paper. Four different droplet breakup modes were observed, namely conical shape-conical jetting, ellipsoidal shape-conical jetting, ellipsoidal shape-filamentous breakup and cylindrical shape-filamentous breakup. The conversion of breakup modes was discussed with the electric capillary number (Ca)-surfactant concentration (CSDBS) phase diagram and the droplet elongation process. The mechanism validated here is that the lobes appear in all breakup modes, and the liquid volume at the both ends of droplet differentiate the breakup modes under different conditions. Different from previous studies, the criterion of droplet breakup modes was proposed based on the interfacial dynamics instead of the bulk phase properties. By analogy with stress–strain relationship, it is found that the electrostatic pressure shows a linear relationship with droplet specific surface area during the droplet elongation process, and the slope K could be employed to identify different breakup modes. These findings are of great significance to the promotion and application of electric-induced droplet breakup.

Low volumetric-energy-density caused by low tap density of nanomaterial seriously restricts the application of nanomaterial in lithium-ion batteries. Here, to solve this problem, micron-sized Fe2O3 secondary particles (MFSPs) with high tap density (2.8 g cm−3) are synthesized via a facile way. As a result, ultrahigh volumetric-energy-density of 1490 mA h cm−3 is obtained after 100 cycles at C/2 (∼500 mA g−1). Densely packed structure of MFSPs exhibits well structural stability and electrical conductivity. For the high areal mass loading of 4.02 mg cm−2, an areal capacity about 3 mA h cm−2 is achieved.

Alkali-surfactant-polymer (ASP) flooding is a high-efficient chemical enhanced oil recovery technology and has been utilized on a large scale in the oilfield. Nevertheless, the produced water treatment from ASP flooding is a great challenge to be resolved. In this paper, the separation mechanism and floating rules of oil droplet in ASP flooding produced liquid are experimentally investigated. The synergistic action of alkali, surfactant and polymer is systematically explored. The results showed that the electrostatic shielding effect induced by excessive sodium ions will lead to the curl of polymer chains and the decrease of viscosity, as a result the floating speed of oil droplet surrounded by ASP solution will increase. The solubilization of surfactant micelles will also reduce the viscosity of ASP solution, which is benefit to the separation of oil droplet in ASP flooding produced liquid. Furthermore, correction for the drag coefficient of oil droplet in ASP solution is developed.

The separation characteristics of W/O emulsion were investigated under ultrasonic standing wave field in this paper. The effects of the irradiation time, acoustic intensity, frequency, oil viscosity, and oil-water interfacial tension on the separation characteristics of emulsion were studied in details. It was proved that there existed an optimal irradiation time, acoustic intensity and oil-water interfacial tension to achieve the maximum separation efficiency in ultrasonic treatment process. Excessive long irradiation time had little effect on improving the dehydration rate of emulsion but rather increased unnecessary processing time. Excessive high acoustic intensity caused the occurrence of acoustic cavitation phenomenon. The acoustic cavitation would cause the aggregated droplets to be dispersed by oscillating bubbles or even emulsified again by high speed micro jets. The acoustic cavitation threshold is effectively and accurately obtained by a spectral analysis method. The micro acoustic streaming which resulted from the attenuation of acoustic energy occurred with the increase of frequency. It sheared the aggregated droplets, destroyed the stable droplets banding and reduced the separation efficiency of emulsion. The excess surfactant adsorbed on the oil-water interface resulted in the increase of the interfacial film strength, which hindered the coalescence process of droplets and reduced the separation efficiency.

The breakup process of aqueous droplet with surfactant suspended in oil under direct current (DC) electric field is investigated in this paper. The characteristics of the breakup process, stretching, necking and breakup, are discussed quantitatively with the electric capillary number Ca and the dimensionless surfactant concentration C∗ which is the ratio of surfactant concentration to the critical micelle concentration. The results show that the presence of surfactant reduces the steady deformation of droplet and significantly decelerates the stretching process, resulting from the redistribution of surfactant molecules within the oil/water interface. The law of droplet stretching process when C∗≥1 indicates that the exchange of surfactant molecules between the bulk phase and the interface could not catch up with the increase of oil/water interfacial area. Ca and C∗ count a great deal to the necking position and the daughter droplet size. The daughter droplet size decreases with the increase of surfactant concentration. These results provide a mechanistic framework to promote the electrocoalescence efficiency of oil/water emulsion and to the application of electric emulsification.