28 research outputs found
Design of porous media burner control system based on arm embedded processor
Because the traditional porous media burner control system has the problems of low control accuracy and long control time, a porous media burner control system based on Advanced RISC Machines (ARM) embedded processor is designed. The hardware of the system is designed through ARM embedded processor, FPGA data acquisition card, power supply circuit, reset circuit and audible and visual alarm module, and the system software is designed based on it. According to the structure of fuzzy controller, fuzzy control rules, assignment table of fuzzy variables, fuzzy control table, and defuzzification, the fuzzy controller is used to fuzzy control the porous media burner. The simulation results show that the designed system has the highest precision and the shortest control time
Gradation segregation analysis of warm mix asphalt mixture
In this study, properties of warm mix asphalt (WMA) compacted with various levels of gradation segregation were evaluated in the laboratory. Six segregated gradations were designed to compare with the control gradation and test sections were paved with the control gradation. Then pavement quality indicator (PQI) and field coring were used to evaluate the uniformity of the WMA test sections with the statistical method. In addition, sieve analysis of the cores was conducted to evaluate the level of segregation. The test results show that gradation segregation has a remarkable effect on water stability, high-temperature stability, low-temperature cracking, and tensile strength of WMA mixtures. Statistical analysis results show that the levels of segregation in localized areas are quite typical because the air void contents follow a normal distribution and the mixtures along the central line are denser than other areas. Sieve analyses of the cores show that most places of the typical segregated localized areas in the test sections have no segregation or low-level segregation, so the construction quality is good. It also shows that the air void content increases as the gradation gets coarser, which is consistent with laboratory test results
Experimental Study of Pulsating Heat Pipes Filled with Nanofluids under the Irradiation of Solar Simulator
Developing renewable energy technologies, especially solar technology, is of vital importance to cope with increasing energy consumption. The existing solar thermal systems have the disadvantages of capturing solar energy inefficiently and needing additional pumping power to circulate the working fluid. A concept of a direct absorption pump-free solar thermal system that combines the advantages of nanoparticles and pulsating heat pipes (PHP) is proposed in this work. The effects of a variety of parameters including nanoparticle types, nanoparticle concentration, and nanofluid filling rate on the performance of PHP were studied. It was found that PHP has the best filling rate (80â90%) making the best heat transfer performance and minimizing the thermal resistance. The concentration of nanoparticles affects the input power of the pulsating heat pipe and thus the operation of the PHP. The nanofluid with relatively low concentration cannot absorb enough solar energy to drive the PHP to operate normally. Experimental research shows that the new solar thermal system can absorb solar energy efficiently and transfer the heat into the targeted area spontaneously, which may be an approach for future solar thermal utilization
Deep learning pathological microscopic features in endemic nasopharyngeal cancer: Prognostic value and protentional role for individual induction chemotherapy
Abstract Background To explore the prognostic value and the role for treatment decision of pathological microscopic features in patients with nasopharyngeal carcinoma (NPC) using the method of deep learning. Methods The pathological microscopic features were extracted using the software QuPath (version 0.1.3. Queen's University) in the training cohort (Guangzhou training cohort, n = 843). We used the neural network DeepSurv to analyze the pathological microscopic features (DSPMF) and then classified patients into highârisk and lowârisk groups through the timeâdependent receiver operating characteristic (ROC). The prognosis accuracy of the pathological feature was validated in a validation cohort (n = 212). The primary endpoint was progressionâfree survival (PFS). Results We found 429 pathological microscopic features in the H&E image. Patients with highârisk scores in the training cohort had shorter 5âyear PFS (HR 10.03, 6.06â16.61; P < .0001). The DSPMF (Câindex: 0.723) had the higher Câindex than the EBV DNA (Câindex: 0.612) copies and the N stage (Câindex: 0.593). Furthermore, induction chemotherapy (ICT) plus concomitant chemoradiotherapy (CCRT) had better 5âyear PFS to those received CCRT (P < .0001) in the highârisk group. Conclusion The DSPMF is a reliable prognostic tool for survival risk in patients with NPC and might be able to guide the treatment decision
A FBG-OCT Catheter to Reconstruct Vascular Shape in Intravascular Optical Coherence Tomography
Study on applicability of data collection frequency for heavy-duty vehicles based on remote monitoring
The remote online system of heavy-duty vehicles is composed of vehicle terminal and monitoring platform based on the specified communication protocol, data format and data transmission frequency, which is an important embodiment of heavy-duty vehicle pollution control in the application for Internet of Vehicles. The influence of different collection frequencies and compute cycles on vehicle energy consumption and emission calculation is studied in this paper. The calculation errors of mileage, vehicle fuel consumption per 100 kilometers and emission factors of 14 collection frequencies and 7 compute cycles were calculated by continuously monitoring the emission and energy consumption data for 10 heavy-duty vehicles uploaded in 1 month. The result shows that decreasing the data collection frequency will lead to the increase of error and the decrease of correlation, while increasing the computing cycle can reduce the error. When the calculation error is 1%, 5% and 10%, the collection frequency shall be at least 0.5Hz, 0.2Hz and 0.1Hz, and the computing cycle shall be greater than 1800 seconds, 3600 seconds and 7200 seconds. The study content of this paper provides the theoretical foundation for the application and storage of remote monitoring data of heavy-duty vehicles, and provides a solution to the waste of data storage space caused by the problem of remote monitoring big data set
The Role of Work Engagement in the Association between Psychological Capital and Safety Citizenship Behavior in Coal Miners: A Mediation Analysis
With the development of science and technology and the increasing importance attached by to these domains by the state and government departments in recent years, Chinaâs coal production and safety supervision level continue to increase. However, the prevalence of frequent coal mine safety accidents has not been effectively curbed. The main purpose of this study was to explore the mediating role of work engagement in the relationship between psychological capital and safety citizenship behavior among Chinese coal miners. Data for 317 coal miners were collected from five coal and energy enterprises. The Psychological Capital Questionnaire (PCQ), the Job Engagement Scale (JES), and the Safety Citizenship Behavior Scale (SCBS) were used to evaluate the coal minersâ psychological capital, work engagement, and safety citizenship behavior. The causal steps approach and bootstrap Method were used in this study to assess the proposed mediation models. A correlation analysis indicated that psychological capital, work engagement, and safety citizenship behavior were significantly correlated with each other. Furthermore, the mediation analysis showed that work engagement mediated the relationship between psychological capital and safety citizenship behavior. Psychological capital does not only have a direct impact on coal minersâ safety citizenship behavior, but it also has an indirect impact on coal minersâ safety citizenship behavior via work engagement. Therefore, effectively enhancing an individualâs psychological capital and work engagement may be a basic factor determining coal minersâ safety citizenship behavior, which further promotes safety production within the enterprise
Mom, dad, put down your phone and talk to me: how parental phubbing influences problematic internet use among adolescents
Abstract Background The positive association of parental phubbing with internalising and externalising problems among adolescents has gained academic traction. To date, limited research has investigated the association of parental phubbing and adolescentsâ Problematic Internet Use (PIU). Furthermore, the mechanism underlying this association is largely unknown. These gaps limit our understanding of family-related issues affecting PIU among adolescents. The present study explores whether there is a relation between parental phubbing and PIU and investigates the mechanisms underlying this relation among adolescents. Methods The participants were 495 junior high schoolers aged 11â15 years. Participants completed questionnaires on their experiences with PIU, parental phubbing, parentâchild relationships, and basic psychological needs satisfaction. Results The results showed a direct and indirect positive association between parental phubbing and PIU. Furthermore, parental phubbing indirectly influenced PIU and was mediated by the parentâchild relationship and basic psychological needs satisfaction, respectively. Moreover, the parentâchild relationship and basic psychological needs satisfaction were sequentially mediated. Conclusions Our study highlights the crucial role of parents in the development of adolescent PIU and provides theoretical and practical guidelines for PIU prevention and intervention
Can Glacial SeaâLevel DropâInduced Gas Hydrate Dissociation Cause Submarine Landslides?
We conducted twoâdimensional numerical simulations to investigate the mechanisms underlying the strong spatiotemporal correlation observed between submarine landslides and gas hydrate dissociation due to glacial seaâlevel drops. Our results suggest that potential plastic deformation or slip could occur at localized and small scales in the shallowâwater portion of the gas hydrate stability zone (GHSZ). This shallowâwater portion of the GHSZ typically lies within the area enclosed by three points: the BGHSZâseafloor intersection, the seafloor at âŒ600 m below sea level (mbsl), and the base of the GHSZ (BGHSZ) at âŒ1,050 mbsl in lowâlatitude regions. The deep BGHSZ (>1,050 mbsl) could not slip; therefore, the entire BGHSZ was not a complete slip surface. Glacial hydrate dissociation alone is unlikely to cause largeâscale submarine landslides. Observed deepâwater (much greater than 600 mbsl) turbidites containing geochemical evidence of glacial hydrate dissociation potentially formed from erosion or detachment in the GHSZ pinchâout zone.
Plain Language Summary
Many submarine landslides spatiotemporally correlate with gas hydrate dissociation. However, direct mechanical evidence supporting whether the overpressure and deformation due to glacial seaâlevel dropâinduced hydrate dissociation are adequate for triggering submarine landslides is lacking. Here, we present twoâdimensional thermalâhydraulicâchemical and geomechanical models of a gasâhydrate system in response to glacial seaâlevel drops and conduct sensitivity analyses of the model behavior under a wide range of key conditions from a global perspective. Our simulations suggest that glacial hydrate dissociation might induce plastic deformation or slip at localized and small scales only possibly within the shallowâwater portion of the hydrate stability zone. The deep part (>1,050 m below sea level) of the bottom boundary of the hydrate stability zone could not slip; therefore, the entire bottom boundary of the hydrate stability zone was not a complete slip surface. We demonstrate that glacial hydrate dissociation alone is unlikely to trigger largeâscale submarine landslides. Our work highlights the vicinity of the upper limit of the hydrate stability zone (where the base of the hydrate stability zone intersects the seafloor) as an important area for investigating overpressure and focused fluid flow, localized plastic deformation or slip, and downslope sediment transport related to glacial hydrate dissociation.
Key Points
Glacial hydrate dissociation might cause potential plastic deformation or slip at localized and small scales in shallow parts of the GHSZ
The large deformation surface at the BGHSZ boundary of the potential plastic deformation zone was not a complete slip surface
Glacial seaâlevel dropâinduced gas hydrate dissociation alone is unlikely to have caused largeâscale submarine landslide
Elevated expression of HIGD1A drives hepatocellular carcinoma progression by regulating polyamine metabolism through c-MycâODC1 nexus
Abstract Background Hypoxia contributes to cancer progression through various molecular mechanisms and hepatocellular carcinoma (HCC) is one of the most hypoxic malignancies. Hypoxia-inducible gene domain protein-1a (HIGD1A) is typically induced via epigenetic regulation and promotes tumor cell survival during hypoxia. However, the role of HIGD1A in HCC remains unknown. Methods HIGD1A expression was determined in 24 pairs of human HCC samples and para-tumorous tissues. Loss-of-function experiments were conducted both in vivo and in vitro to explore the role of HIGD1A in HCC proliferation and metastasis. Results Increased HIGD1A expression was found in HCC tissues and cell lines, which was induced by hypoxia or low-glucose condition. Moreover, HIGD1A knockdown in HCC cells arrested the cell cycle at the G2/M phase and promoted hypoxia-induced cell apoptosis, resulting in great inhibition of cell proliferation, migration, and invasion, as well as tumor xenograft formation. Interestingly, these anti-tumor effects were not observed in normal hepatocyte cell line L02. Further, HIGD1A knockdown suppressed the expression of ornithine decarboxylase 1 (ODC1), a rate-limiting enzyme of polyamine metabolism under c-Myc regulation. HIGD1A was found to bind with the c-Myc promoter region, and its knockdown decreased the levels of polyamine metabolites. Consistently, the inhibitory effect on HCC phenotype by HIGD1A silencing could be reversed by overexpression of c-Myc or supplementation of polyamines. Conclusions Our results demonstrated that HIGD1A activated c-MycâODC1 nexus to regulate polyamine synthesis and to promote HCC survival and malignant phenotype, implying that HIGD1A might represent a novel therapeutic target for HCC