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Aimed to clarify the correlation characteristics between the internal partial discharge (PD) in the negative direct current (DC) gas‐insulated system (GIS) and gas pressure, and to establish an insulation fault diagnosis method based on decomposition component analysis, this study on PD decomposition of sulphur hexafluoride (SF6) was conducted under different pressures on the basis of constructing a SF6 decomposition experimental platform under DC PD. A stainless steel needle‐plate electrode was used to simulate the insulation defects of metal protrusions in GIS. SOF2, SO2 F2, CO2, SO2, and CF4 data generated from SF6 decomposition were obtained under different pressures. The variation law of component concentration and effective characteristic ratio with pressure were analysed in detail. In addition, a mathematical formula for pressure and decomposition components was deduced according to gas micro‐ionisation theory. The effective content and formation rate were defined to validate the relationship. Results show that the concentration of SF6 decomposition components decreased gradually with increasing pressure with a strong regularity. Furthermore, the relationship between pressure and component concentration derived from the theory can explain the relationship between the effective content of SF6 decomposition components and the effective formation rate and pressure variations. [ABSTRACT FROM AUTHOR]

Introduction: The clinical influence of smoking cessation on pain tolerance before surgery and postoperative pain perception is not fully understood. This clinical study investigated the effect of smoking cessation on pain threshold during the perioperative period in patients undergoing hepatic resection.Methods: We enrolled 148 male patients (68 non-smokers and 80 abstinent smokers) who underwent hepatic resection and received postoperative patient-controlled intravenous analgesia. Patients were tested for preoperative pain thresholds in response to electrical stimuli. We recorded the cumulative amount of extra morphine equivalent required during the first 48h after surgery. Pain intensity was evaluated at 1h, 6h, 24h and 48h after surgery using the visual analogue scale (VAS). Additionally, button-pressing consumption was recorded by a patient-controlled analgesia (PCA) pump.Results: The groups did not differ with respect to baseline clinical characteristics. Compared with non-smokers, abstinent smokers exhibited lower pain thresholds before surgery and demanded a larger quantity of extra morphine equivalent during the first 48h after surgery. Abstinent smokers also exhibited more severe postoperative pain than non-smokers. Postoperative complications, such as nausea, vomiting, dizziness, sedation, and respiratory depression, did not significantly differ between the two groups.Conclusions: In this study, smokers deprived of cigarettes exhibited decreased pain tolerance before surgery and required a larger quantity of postoperative extra morphine equivalent than non-smokers. Health care providers must be aware of the potential for increased narcotic requirements in smokers. [ABSTRACT FROM AUTHOR]

Boron is an attractive high-energy fuel additive. But it could not burn efficiently in practical systems due to its high ignition temperature and slow burning velocity. Finding methods to enhance the combustion of boron is desired. This work focused on the combustion characteristics of boron submicroparticles with and without plasma discharges in a hot environment supported by CH 4 /N 2 /O 2 flat flame based on the optical diagnostics. The boron submicroparticles were dispersed by the nebulization method to control the agglomeration. The well-dispersed boron flame exhibited two different burning modes, depending on the ambient temperature. As the ambient temperature was above 1520 K, the boron flame showed definitely two-stage characteristics where the upstream of particle flow was yellow, corresponding to the first-stage flame, while the downstream was green and diffusive, corresponding to the second-stage flame. The first-stage and second-stage burn times were respectively in the range of 0.46–1.08 ms and 0.92–1.87 ms, as the ambient temperature decreased from 1752 K to 1520 K. The chemical kinetics-controlled mechanism was confirmed by the nearly linear size dependence of the burn time (d 1 law). Nevertheless, as the ambient temperature was below 1520 K, the boron submicroparticles were partially burned or oxidized, exhibiting a mildly orange stream. This mild boron flame could be enhanced using a plasma discharge. The ignition delay time was shortened from 3.06 ms to 0.77 ms when the discharge was introduced at the ignition delay stage. The two-stage combustion characteristics occurred when the discharge was introduced at the combustion stage. [ABSTRACT FROM AUTHOR]

Background and objectives: The dismal prognosis of gastric cancer patients is a global problem. We aim to evaluate the clinicopathologic features and prognostic factors of proximal and distal gastric cancer. Materials and methods: Gastric cancer cases diagnosed and treated at the same surgical unit between 2007 and 2010 were reviewed. Follow-up data from all patients were collected for at least 5 years until 2015. A total of 964 patients were studied (distal gastric cancer [DG], n=777 and proximal gastric cancer [PG], n=187). Results: DG patients had a relatively higher percentage of females, more thorough therapy (R0 [D0/D1/D2]), fewer combined organ resections, younger age, smaller tumors (=5 cm), shorter surgery durations, less blood loss during surgery, and a relatively lower percentage of nodal metastases and a TNM stage of 4 (p=0.05). A significantly higher 5-year survival rate was observed in DG patients compared to PG patients (DG: 51%, PG: 28%; p=0.001). A multivariate analysis demonstrated that tumor size, blood loss during surgery, surgery approach of lymph node dissection, treatment with palliative surgery, histopathologic type, TNM stage, and tumor location were independent predictors of poor outcome. Conclusion: The different characteristics and prognosis of DG and PG cases have implications for the development of guiding strategies for a surgical program and assessment of prognosis of gastric cancer patients based on tumor location. [ABSTRACT FROM AUTHOR]

Mineral transformation and soot formation are the two governing mechanisms for fine particle formation in the early stage of coal combustion. The interaction between the evaporative alkali species and soot, which can have significant effect on fine particle formation, however, is not fully understood. To investigate the interaction between Na and soot in the early stage of coal combustion, we characterized the particles derived from four coals samples, including acid-washed and Na-loaded samples, under both the pyrolytic and oxidizing atmospheres. It was found that Na can reduce the soot yield and particle size under the pyrolysis condition. The Na-doped soot was formed by flame synthesis of vaporized minerals and soot precursors, and the Na content had a strong effect on soot oxidation activity. The Na-soot interaction was found to reduce the fine particle yield in the early combustion stage, as the high Na concentration and strong sooting tendency of a sodium doped bituminous (YK-Na) resulted in a lower fine particle yield. A schematic of the Na-soot interaction pathways is proposed based on the experimental results. Catalyzing soot oxidation and eliminating ultrafine mineral particles were found to be the two principal ways by which Na-soot interaction affects the formation and evolution of fine particles. [ABSTRACT FROM AUTHOR]

This study examined the application of 64-slice spiral double-low computed tomography (CT) to evaluate the degree of coronary artery stenosis. We examined 45 patients with coronary heart disease by 64-slice spiral double-low CT and coronary angiography (CAG) to determine CT accuracy in evaluating coronary artery stenosis. Imaging analysis from 64-slice spiral double-low CT identified 199 segments with coronary stenosis from 45 patients, including 46 segments with mild stenosis, 38 with moderate stenosis and 115 with severe stenosis or artery occlusion. CT analysis agreed with CAG on the identification of the degree of stenosis in 122 segments, with an overall accuracy of 61.3%. The accuracy for serious stenosis or occlusion was the highest at 69.6%. We also found a strong correlation between coronary plaque compositions and the degree of stenosis. Correspondence analysis showed that the presence of soft plaques closely correlated with severe stenosis, whereas mixed plaques closely correlated with moderate stenosis. Overall, 64-slice spiral double-low CT imaging can effectively assess the degree of coronary artery stenosis in patients with coronary heart disease and accurately detect plaque composition. Thus, 64-slice spiral double-low CT imaging can predict the risk of coronary heart disease and the degree of coronary artery stenosis, which is helpful for early diagnosis and treatment of coronary heart disease. [ABSTRACT FROM AUTHOR]

Macrophages and oxidized low-density lipoprotein (ox-LDL) have been verified playing vital roles in the pathogenesis of atherosclerosis (AS). Previous studies demonstrated that microRNA-29a (miR-29a) was upregulated in many atherogenic process and cells, thus acting as an important participant in AS. But the detailed regulation mechanism of miR-29a in AS has not been fully understood. In our study, we demonstrated a positive feedback loop of ox-LDL-SRA-miR-29a. Furthermore, we found that YY1 and STAT1 were upregulated in ox-LDL-stimulating macrophages followed by translocation in the nucleus and binding to the transcriptional promoter region of miR-29a, thus leading to the increase of miR-29a expression. In addition, we demonstrated that JAK1/2 signaling was involved in miR-29a upregulation. Finally, we found that miR-29a played important roles in the secretion of proinflammation factors and lipid uptake in macrophages. We uncovered the molecular mechanism and provide novel insights into the function and regulatory network of miR-29a expression regulated by ox-LDL in macrophages. [ABSTRACT FROM AUTHOR]

An experimental and theoretical investigation is conducted on the combustion of pulverized coal particle streams in either conventional or oxy-fuel conditions. The laboratory setup consisted of a Hencken flat-flame burner operated at the same temperatures of 1200, 1500 and 1800 K in N 2 and CO 2 environments. The visible light detection technique and the calibrated three-color pyrometry are separately used to characterize the ignition delay time and the luminous char surface temperature. First, experimental results indicate that the ignition delay time is relatively longer in CO 2 environment in heterogeneous mode or even heterogeneous-controlled joint mode. The ignition delay is obviously enhanced in O 2 /CO 2 ambient when the volatile-flame controlled joint mode is prevalent. The model predictions of particle temperature history further reveal that the extra gas flame radiation of CO 2 and the declined difference between the thermal conductivity are two main reasons. Then, during char combustion, the measurement shows that the char surface temperature is lower in an O 2 /CO 2 environment than in an O 2 /N 2 environment. It is noted that the temperature difference between N 2 and CO 2 environments enlarges with the increasing ambient temperature. In contrast to conventional O 2 /N 2 conditions, the lower O 2 diffusivity in CO 2 , the endothermic carbon reaction with CO 2 and the higher heat capacity of CO 2 , which are all temperature dependent, synergistically contribute to the enlargement of char surface temperature differences at high ambient temperature. [ABSTRACT FROM AUTHOR]

Particulate matter (PM) generated from pulverized coal combustion is influenced by a process of vaporization, nucleation and condensation/reaction of semi-volatile minerals. The objective of the work is to identify the controlling mechanism of the enrichment of volatile sodium (Na). Three representative kinds of coal with different rank and mineral content, Zhundong lignite, Hami lignite and high-ash-fusion (HAF) bituminous, were burned in a 25 kW self-sustained pulverized coal combustor. Zhundong lignite, possessing medium rank among the three coal samples, exhibits the highest formation ability of ultrafine PM 0.2 , indicating a prominent effect of mineral content over that of coal rank on PM formation. The size partitioning behavior of sodium is affected by the molar ratio Na 2 O/(SiO 2 +Al 2 O 3 ) instead of the absolute Na content. With this ratio increasing from 0.27 (HAF bituminous) to 20 (Zhundong lignite), the gas-to-particle conversion of Na transits from a surface-reaction controlled process to a nucleation-condensation/coagulation dominated pathway. The Na partitioning behavior of Zhundong lignite is then quantitatively interpreted by a population-balance-based theoretical approach. The model reveals the details on the competing processes of homogeneous nucleation and vapor condensation, resulting in that the simulated final particle mass size distribution exhibits reasonable agreement with the experimental result. The model has also successfully reproduced the d p 0 dependence of Na fraction in the ultrafine size regime from a process of homogeneous nucleation under the decreasing gas temperature from 1420 to 1270 K. [ABSTRACT FROM AUTHOR]

The decomposition characteristics of SF6 gas-insulated equipment remarkably vary under different working pressures (0.3?0.7 MPa). Thus, the influence of pressure should be considered when adopting decomposed components for spark discharge fault diagnosis. A series of experiments on SF6 spark discharge decomposition under various pressures were performed on the spark discharge simulation experimental platform. The influence of pressure on SF6 spark discharge decomposed components were analyzed quantitatively combined with molecule chemical decomposition mechanisms. Results show that the species of spark decomposed components do not vary under different pressures. However, pressure directly affects the accumulated energy of the electrons in the spark channel, leading to diverse dissociation intensities of electrons on SF6. This phenomenon further affects the rate of neutral-neutral molecule and ion-molecule reactions responsible for the decomposed components. Finally, the yields and effective generation rates of decomposed components CF4, SOF4, SO2F2, SOF2, and SO2 decline with varying degrees under increasing pressure. Moreover, mathematic regression equations were derived for the effective generation rates of the components influenced by pressure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanofiber membranes with good microscopic morphology and high porosity containing AKP were successfully prepared. • AKP increased the nanofiber membranes' cell coverage and relative cell viability. • The ordered secondary structure content of AKP showed a positive correlation with the its intermolecular hydrogen bonds. • AKP improved the thermal stability and mechanical properties of nanofiber membranes. Polyvinyl alcohol (PVA) and polyethylene oxide (PEO) nanofiber membranes with high porosity and specific surface area supply a suitable structural environment for cell growth, however the difficulty of cells adhesion to and growth has tremendously limited their application in biomedical materials. In this work, by incorporating Antarctic krill protein (AKP), the problem in cells adhesion and growth is successfully addressed for PVA/PEO nanofiber membranes. Meanwhile, it is worth noting that the problem that AKP is difficult to prepare nanofibers by electrospinning process is also effectively avoided. The intermolecular interactions ensure the uniform dispersion of AKP in the nanofiber membranes. And both the crystal structure content of nanofiber membranes and the ordered secondary structure content of AKP reach the maximum values of 37.41 % and 52.17 % at the AKP content of 20 %. The tensile strength is improved by 13.46 % notably. More importantly, the introduction of AKP enhances cell proliferation and viability and adds more recognition sites for cell attachment, solving the problem of difficult cell adhesion and growth. Thus, as-prepared nanofiber membranes containing AKP can supply suitable structural environment and excellent biocompatibility, for cell growth and reproduction. It is expected to be an essential candidate in biomedical materials with potential application prospects. [ABSTRACT FROM AUTHOR]

Introducing airflow into the low-intensity dry magnetic separator (LIDMS) is an effective means to improve the separating efficiency of ferromagnetic particles under dry conditions. In this study, a multi-physical coupling model was established to compare the separating performance of LIDMS under four typical air supply modes. The result shows that Mode D can maximize the competing force along the normal direction of the drum due to the vertically outward air supply mode, and its separating performance is the best, especially for the particles with a fine diameter. The mechanism of airflow under different modes which enhances the LIDMS is expounded by analyzing the characteristics of the magnetic field and the flow field and calculating the forces on particles with various properties. We expect that this study could provide a reference for the dry separation of magnetic minerals and the development or optimization of LIDMS under airflow conditions. [Display omitted] • The performance of magnetic separation under different air supply modes is compared. • A multi-physical model is established to simulate the magnetic separation process. • The difference in separation performance is explained by analyzing the flow field and forces on particles. • The airflow in a normal direction can maximize the dry magnetic separation efficiency. [ABSTRACT FROM AUTHOR]

A supported PdO nanocatalyst prepared by a facile in situ reduction process followed by an oxidation step showed significantly enhanced activity for the removal of pollutants from natural gas vehicles. The excellent catalytic performance is mainly due to high dispersion of the uniform PdO nanoparticles generated during the novel two-step method. [ABSTRACT FROM AUTHOR]

As an important issue in image processing and computer vision, online visual tracking acts a critical role in numerous lines of research and has many potential applications. This paper presents a novel tracking algorithm based on subspace representation with continuous occlusion handling, the contributions of which are threefolds. First, this paper develops an effective objective function to represent the tracked object, in which the object reconstruction, the sparsity of the error term and the spatial consistency of the error term are simultaneously considered. Then, we derive an iterative algorithm to solve the proposed objective function based on the accelerated proximal gradient framework, and therefore obtain the optimal representation coefficients and the possible occlusion conditions. Finally, based on the proposed representation model, we design an effective likelihood function and a simple model update scheme for building a robust tracker within the particle filter framework. We conduct many experiments to evaluate the proposed tracking algorithm in comparisons with other state-of-the-art trackers. Both qualitative and quantitative evaluations demonstrate the proposed tracker achieves good performance. [ABSTRACT FROM AUTHOR]

Pyrolysis and oxidation of heavy oil is the fundamental of in situ combustion process. Heavy oil from Xinjiang, China and its main components, saturates, aromatics and resins (SAR), were used as samples to study their pyrolysis and oxidation characteristics with a thermogravimetric analyzer (TGA) and a fixed-bed reactor. The DTG curves and the detected gas products differed between pyrolysis and oxidation of the heavy oil. Elemental analysis of pyrolysis and oxidation cokes indicates that low temperature oxidation (LTO) primarily accounted for the differences. Compared with independent pyrolysis and oxidation of saturates, aromatics and resins, they showed little interactions during co-pyrolysis, but significant interactions during co-oxidation. When saturates co-oxidized with aromatics or resins, both the beginning temperatures of LTO were increased, the DTG curve at high temperature oxidation (HTO) remained unchanged during co-oxidation with aromatics, while the DTG peaks at HTO changed from two into one during co-oxidation with resins. Co-oxidation of aromatics and resins showed similar effect at HTO. Oxygen-adding reactions of saturates, aromatics, and resins at low temperature promoted the polycondensation between intermediate products and altered the subsequent cracking reactions, which caused special characteristics during their co-oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] The nano-architectured CeO 2 -ZrO 2 -Nd 2 O 3 composite oxide support materials were successfully synthesized by a co-precipitation combined with a simple mechanical mixing with a serious amount of trialkyl amine (N235, N (C n H 2 n +1), n = 8–10), and the obtained Rh-based catalysts exhibit excellent catalytic activity and thermal stability. • High performance CeO 2 -ZrO 2 -Nd 2 O 3 is successfully prepared by a simple method. • N235 plays a key role in the formation of loose morphology. • The loose morphology improves the thermal stability of the material. • The prepared Rh-only three-way catalyst shows an excellent catalytic performance. Ceria-zirconia-neodymia composites are synthesized by a co-precipitation combined with mechanical mixing of trialkyl amine (N235, N (C n H 2 n +1), n = 8–10) process and the effect of the novel surfactant N235 on the properties of ceria-zirconia-neodymia composites and their supported Rh-only three-way catalysts are investigated. The physicochemical properties of the samples before and after aging treatment are characterized by N 2 adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H 2 -temperature programmed reduction (H 2 -TPR), oxygen storage capacity (OSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), particle size distribution analysis and CO chemisorption. The results indicate that the introduction of surfactant N235 is beneficial to form loose and porous morphology, which contributes to the high surface area, large OSC, superior redox property and high Rh dispersion, and thus the improved catalytic activity for Rh-only three-way catalyst is obtained. The more dosage of N235, the superior catalytic performance for Rh catalyst is. The modified support material (the molar ratio of N235 and total metals is 0.21:1) displays relatively better textural, structural, redox and OSC properties, and the corresponding fresh (Rh/CZN3f) and aged (Rh/CZN3a) catalysts deliver superior catalytic activity. [ABSTRACT FROM AUTHOR]

Particle impaction on a droplet surface directly affects the particle capture by the droplet, and this phenomenon is the basic process of wet scrubbing and wet deposition. The experimental system is established to in-situ observe the behavior of micron particles impacting on the liquid surface. 50–200 μm hydrophobic PMMA and PS particles were used. The particles showed two types of motion behavior, namely, submergence and oscillation, after impaction onto the liquid surface. During particle sinking, the advancing contact angle remained constant. The shape of the liquid surface met the Young–Laplace equation under the quasi-static assumption. After the angle of the three-phase line reached the critical value, the liquid surface was closed, and the particle submerged. A small bubble formed, adhering to the particle trailing surface. If the particle velocity decreases to zero before the angle of the three-phase lines reaches the critical value, the particle will reverse the direction of its motion. When the particle moves to the horizontal liquid surface, the movement ceases. Reciprocating oscillation behavior was not observed. During particle reversion, the receding contact angle gradually decreased and then remained unchanged. The large contact angle hysteresis is the main cause of failure observation in rebound motion mode in the experiment. The changing rule of the critical submergence/oscillation velocity with the particle diameter and surface tension coefficient was studied. As the particle diameter increases, the critical submergence/oscillation velocity decreases. As the surface tension coefficient increases, the critical submergence/oscillation velocity increases. The observed critical submergence/oscillation velocity in this experiment demonstrated the accuracy of the proposed model. [ABSTRACT FROM AUTHOR]

Dispersed palladium on the high-surface-area ceria support is synthesized via one-step flame-assisted spray pyrolysis method, which applies a highly-quenched stagnation-point flame controlling catalyst sizes and structures. The X-ray photoelectron spectroscopy (XPS) spectra of Pd show a significantly high binding energy for flame-made Pd/CeO 2 catalysts, possessing a value of 1.7 eV larger than the reference value in literature. It suggests that the partial electron transfer occurs from metal Pd to their supports during the synthesis process, which creates Pd electron-deficient (cationic Pd δ+ ) and Ce electron-rich (anion Ce δ − ), respectively. The catalytic activities of CH 4 oxidation are performed over the temperatures ranging from 200 °C to 600 °C. In comparison with inert support materials, the synergistic effect is found between palladium and support ceria that leads to the enhanced catalytic activity. During the heating and cooling cycles of CH 4 oxidation, Pd/CeO 2 catalysts exhibit an exceptional inhibition effect against the sintering of Pd cluster and its dispersion decrement, which is related to strong electronic interaction of metal-support interfaces induced by the aforementioned partial electron transfer. [ABSTRACT FROM AUTHOR]

Background: Utidelone, a genetically engineered epothilone analogue, has shown promise as a potential treatment for breast cancer in phase 1 and 2 trials. The aim of this phase 3 trial was to compare the efficacy and safety of utidelone plus capecitabine versus capecitabine alone in patients with metastatic breast cancer.Methods: We did a multicentre, open-label, superiority, phase 3, randomised controlled trial in 26 hospitals in China. Eligible participants were female patients with metastatic breast cancer refractory to anthracycline and taxane chemotherapy regimens. We randomly assigned participants (2:1) using computer based randomisation and block sizes of 6 to a 21-day cycle of either utidelone (30 mg/m2 intravenously once per day on days 1-5) plus capecitabine (1000 mg/m2 orally twice per day on days 1-14), or capecitabine alone (1250 mg/m2 orally twice per day on days 1-14), until disease progression or unacceptable toxicity occurred. Patients, physicians, and assessors were not masked to treatment allocation; however, an independent radiology review committee used to additionally assess response was masked to allocation. The primary endpoint was centrally assessed (by an independent radiology review committee) progression-free survival, and analysed using the Kaplan-Meier product-limit method in the intention-to-treat population. Safety was assessed in all participants who received at least one dose of study drug. Follow-up is ongoing. This study is registered at ClinicalTrials.gov, number NCT02253459.Findings: Between Aug 8, 2014, and Dec 14, 2015, we enrolled and randomly assigned 270 patients to treatment with utidelone plus capecitabine, and 135 to capecitabine alone. Median follow-up for progression-free survival was 6·77 months (IQR 3·81-10·32) for the utidelone plus capecitabine group and 4·55 months (2·55-9·39) for the capecitabine alone group. Median progression-free survival by central review in the utidelone plus capecitabine group was 8·44 months (95% CI 7·95-9·92) compared with 4·27 months (3·22-5·68) in the capecitabine alone group; hazard ratio 0·46, 95% CI 0·36-0·59; p<0·0001. Peripheral neuropathy was the most common grade 3 adverse event in the utidelone plus capecitabine group (58 [22%] of 267 patients vs 1 [<1%] of 130 patients in the capecitabine alone group). Palmar-plantar erythrodysaesthesia was the most prominent grade 3 adverse event in the capacitabine alone group (in 10 [8%] of 130 patients) and was the next most frequent grade 3 event in the utidelone plus capecitabine group (in 18 [7%] of 267 patients). 16 serious adverse events were reported in the combination therapy group (diarrhoea was the most common, in three [1%] patients) and 14 serious adverse events were reported in the monotherapy group (the most common were diarrhoea, increased blood bilirubin, and anaemia, in two [2%] patients for each event). 155 patients died (99 in the combination therapy arm, 56 in the monotherapy arm). All deaths were related to disease progression except for one in each group (attributed to pericardial effusion in the combination therapy group and dyspnoea in the monotherapy group) that were considered possibly or probably treatment-related.Interpretation: Despite disease progression with previous chemotherapies, utidelone plus capecitabine was more efficacious compared with capecitabine alone for the outcome of progression-free survival, with mild toxicity except for peripheral sensory neuropathy, which was manageable. The findings from this study support the use of utidelone plus capecitabine as an effective option for patients with metastatic breast cancer.Funding: Beijing Biostar Technologies, Beijing, China. [ABSTRACT FROM AUTHOR]

To figure out the influence rules of trace H2O on SF6 decomposition characteristic components under spark discharge, a series of spark discharge decomposition experiments with various H2O contents were performed using needle-plate electrode to simulate metal protrusion insulation defect. The changing rules and mechanisms of five decomposition characteristic components were achieved quantitatively, indicating that no matter how much H2O was, there exist five main decomposition components: CF4, SOF2, SO2, SOF4 and SO2F2. The contents of the five decomposition components increased with the time extended, and resulting in the contents of SF6 spark decomposition components by the order: SOF2 > SO2F2 > SOF4 > SO2 > CF4. Additionally, the higher H2O content is, the stronger promoting effect on the generation of SO2F2, SOF2, SOF4 and SO2 is. [ABSTRACT FROM AUTHOR]

To prepare novel medical dressings with excellent comprehensive properties, this work uses the polyvinyl alcohol-allyl polyethylene glycol graft copolymer (PVA-g-APEG) synthesized in our previous work as a modifier. The polyvinyl alcohol (PVA)/polyethylene oxide (PEO)/PVA-g-APEG nanofiber membranes with different PVA-g-APEG contents are successfully prepared by electrospinning technology. The biomimetic natural extracellular matrix structure of nanofiber membranes is achieved by regulating the PVA-g-APEG contents. As the content of PVA-g-APEG is 4 wt%, the diameter distribution of nanofibers is the narrowest. The average diameter of nanofibers reaches the minimum value of 267.18 nm, and the porosity of nanofiber membranes reaches the maximum value of 77.90%. Meanwhile, nanofiber membranes possess excellent biocompatibility. The absorption capacity of the nanofiber membranes for different liquids is improved with higher PVA-g-APEG content. The nanofiber membranes become soft and slippery after contact with liquid, effectively avoiding adhesion with cells. The cell proliferation rate is higher than 100%, and the cytotoxicity grade is 0. Additionally, the mechanisms of intermolecular interactions, crystallization and mechanical properties change of nanofiber membranes are discussed systematically. It provides a method and idea for preparing high-strength PVA/PEO nanofiber membranes and realizing the practical application of PVA/PEO composite systems in medical dressings. [Display omitted] [ABSTRACT FROM AUTHOR]

The plasma-assisted ignition enhancement of pulverized lignite particles is intensively studied in a laminar, upward Hencken flat-flame burner. By applying a pair of pin-to-pin electrodes with a high-voltage DC power supply, the apparent reductions of ignition delay time, about 0.8–3.5 ms, are observed for all three ambient temperatures, 1200 K, 1500 K and 1800 K, across which the ignition mode transits from heterogeneous ignition (HI) to hetero-homogeneous combined one. Concentrated on 1200 K ambience where HI mode prevails, the plasmas-induced reduction of ignition delay time as a function of the applied voltage (0–20 kV) is explored, in which the chemical effect is found to play a key role in cases with voltage less than 3 kV. Then, under the conditions of different oxygen mole fractions, the discharge mechanisms and the reductions of ignition delay time are further examined to distinguish the chemical and thermal effects on the ignition enhancement. Finally, the gas temperature rise, both measured and predicted at a point located 6 mm above the electrodes, verifies the thermal effect. This paper provides a preliminary understanding of plasma-assisted ignition mechanisms on dispersed coal particles that may be applied in practical combustion system. [ABSTRACT FROM AUTHOR]

Two in situ optic methods on CH ∗ chemiluminescence and coal particle temperature, are newly applied to investigate the devolatilization/homogeneous and heterogeneous ignition behaviors of dispersed coal particle streams, with ambient temperature from 1200 K to 1800 K and oxygen mole fractions from 10% to 30%. The dispersed coal particles of 65–74 μm are injected into an optical Hencken flat-flame burner by a novel de-agglomeration feeder. First, the consecutive images through multiple filters near CH ∗ emission band, centered at 420 430 and 440 nm, are exquisitely processed to subtract the interferences from continuum blackbody radiation of particles and soots in the CH ∗ band. Then, the signal of CH ∗ chemiluminescence is capable of providing a good indicator of the coal devolatilization process. Secondly, 3 color pyrometry is adopted to detect particle surface temperature and determine the heterogeneous ignition delay time. The prevalent devolatilization/homogeneous-ignition are observed at high temperatures (1500 and 1800 K) with apparent CH ∗ signals, whereas CH ∗ emission can rarely be detected in the initial stage of 1200 K case that implies a dominated heterogeneous ignition mode. The effect of oxygen concentration on devolatilization is further discussed. The particles temperatures history after injected into Hencken burner are represented by 3 color pyrometry based on a two stage principle, and thus the role of oxygen in determining particle temperature and heterogeneous ignition is finally examined. [ABSTRACT FROM AUTHOR]

Formation of ultrafine particles during coal combustion is believed to be governed by the solid–vapor–particle process of evaporative inorganic species. In this work, a down-fired flat-flame burner with a two-stage dilution sampling system were used to characterize the particulate matter formed in the early stage of high-sodium coal combustion. It was found that 33.9% of Na and 33.1% of Mg in the coal were enriched in the ultrafine particles through the solid–vapor–particle process at 1500 K, 20% O 2 . The control mechanisms of homogeneous condensation and surface reaction were identified with elemental particle size distributions. Below 1500 K, either increasing the oxygen concentration or the ambience temperature lead to a higher ultrafine particle yield, which was caused by the intensification of gas-phase release. At 1700 K, however, the gas-to-particle conversion process became the control step, resulting in reduced particle yield with lower molar fraction of Na, Mg and S. This change in particle elemental composition is correlated to the thermodynamic behavior of the Na–Mg–Ca–Si–S–Cl system, which is of great importance during the gas-to-particle conversion process at high temperature. [ABSTRACT FROM AUTHOR]

With the increasing use of low-rank coal, the upgraded semi-char produced through low-temperature pyrolysis of lignite is one of promising alternatives towards the clean and high efficient utilization. The co-firing of these pyrolytic semi-chars with parent coals has received more attention. In this paper, a kind of semi-char, produced from Hulunbuir (HB) lignite under a pyrolysis temperature of 504 °C, was burned in a 25 kW self-sustained pulverized coal combustor. Different mass blending ratios of semi-char (0%, 40%, 60% and 100%) were used. The results indicate that the PM 0.1 yield from pure combustion of HB lignite is ∼1.6 times of that from semi-char. The PM 0.1 yields of the coal/char blends are much less than the linear summation of yields of two blending fuels without considering their interactions. As for coarser PM mode, the reductions still exist for both PM 0.1–1 and PM 1–10 particles. The different PM yields of pure combustion cases are attributed to less volatile mineral species and also less fragmentation degree of semi-chars during combustion. A mechanism is postulated for PM reduction during the combustion of coal blends. PM 0.1 amounts are decreased since the volatilized mineral species is considerably scavenged by the previously formed semi-char surfaces, as partly evidenced from a time scale analysis. The scavenged compounds then serve as “glue” to convert ash particles to larger agglomerates, which may result in the reduction of PM 0.1–10 yields. [ABSTRACT FROM AUTHOR]

• Thermal stability analysis of As clarifies dominance of chemical adsorption. • As amount adsorbed by ash in flue gas is far less than ash's adsorption capacity. • Chemical adsorption by ash is mainly through the joint action of Ca and Fe in ash. • As Adsorption by high-Ca ash increases with temperature due to the stable product. • Instability of Fe 2 O 3 product make As amount adsorbed by high-Fe ash peak at 800 °C. Arsenic (As) transformation during flue-gas cooling process determines terminal As emission. In this study, the dominant role of chemical adsorption in gaseous As transformed to ash was confirmed. Dynamic curves of As 2 O 3 adsorption by ash at 500–900 °C were obtained. The adsorbed As amount increased linearly with time, far from reaching saturation, and the maximum amount was approximately 10 times the As content in ash collected from power plant dust collectors, indicating that the actual capacity of ash was far higher. Analysis of As form and elemental distribution directly proved that chemical adsorption by ash was mainly through the joint action of Ca and Fe, and its correlation with other components was weak. At 500–900 °C, as temperature increased, the amount of As adsorbed by CaO gradually increased, whereas that of Fe 2 O 3 first increased and then decreased. The adsorption product of CaO was stable, whereas certain forms of products of Fe 2 O 3 released at 800 °C. Therefore, as temperature increased, the amount of As adsorbed by ash with high Fe content first increased and then decreased, reaching a maximum at 800 °C °C, whereas that of ash with higher Ca content kept increasing. The strong adsorption capacity of ash with high Ca and Fe contents helps reduce terminal As emission. [ABSTRACT FROM AUTHOR]

[Display omitted] • SF 6 and Ti 3 C 2 (OH) 2 surface have strong interaction during adsorption process. • Structure of SF 6 changes obviously with low-fluorine sulfide formed as a result of chemical adsorption. • Ti 3 C 2 T x terminated by hydroxyl is potential to be a catalyst for SF 6 decomposition. At present, searching for efficient methods to degrade sulfur hexafluoride (SF 6) is a worldwide hotspot. Due to the abundant active groups on the surface, MXene is regarded as an ideal catalyst support. In this paper, the potential active sites of Ti 3 C 2 T x (T = OH, F, O) for SF 6 degradation were studied using density functional theory (DFT) method. The results show the adsorption of SF 6 on Ti 3 C 2 (OH) 2 is significantly stronger than that on Ti 3 C 2 F 2 and Ti 3 C 2 O 2. Among typical adsorption sites on Ti 3 C 2 (OH) 2 , SF 6 exhibited the strongest interaction at OH-1 site. Complex electron orbital interactions occurred between SF 6 and Ti 3 C 2 (OH) 2. Adsorption energy reached −6.739 eV and about 1.414e transferred from Ti 3 C 2 (OH) 2 to SF 6. Structure of SF 6 changed obviously and chemical adsorption occurred in this process. However, on Ti 3 C 2 F 2 and Ti 3 C 2 O 2 , gas–solid interactions were weak and the structures had little change, which was mainly physical adsorption. Compared with common catalysts such as Ag, α ‑Al 2 O 3 and BaTiO 3 , Ti 3 C 2 (OH) 2 showed better catalytic activity for SF 6 degradation. By strong adsorption of the active site on the surface, the degradation products were separated from each other, which weakened SF 6 recombination and promoted the further degradation. The results provide theoretical support for MXene acting as a catalyst to efficiently degrade SF 6. [ABSTRACT FROM AUTHOR]

Background: Platelet and blood coagulation abnormalities frequently occur in cancer patients. Fibrinogen is an important hemostatic factor that regulates the hemostatic pathway. Hyperfibrinogenemia is increasing recognized as an important risk factor influencing cancer development and outcome. However, few reports have investigated the prognostic potential of fibrinogen for predicting the survival of gastric cancer (GC) patients. The primary aim of this study was to evaluate the usefulness of preoperative serum fibrinogen as a biomarker for predicating tumor progression and survival of patients with GC.Patients and Methods: This retrospective study was conducted in GC patients who underwent gastrectomy from 2005 to 2007. Patient demographics, clinicopathological characteristics, preoperative plasma fibrinogen levels and median survival time (MST) were analyzed. Univariate and multivariate proportional hazard analysis of risk factors were used.Results: This study included 1196 patients (885 males and 311 females) with GC, more than half of whom had advanced GCs. Radical lymph node dissection was performed in 71.6 % of these patients. MST was 41.9 ± 32.4 months. Patient survival was significantly affected by family GC history (p <0.05), lymph node dissection mode (p <0.001), tumor size (≥5 cm; p <0.001), tumor location (p < 0.001), poor tumor differentiation (p <0.001), tumor histologic classification (p <0.001), extent of tumor invasion (p <0.001), number of metastatic lymph nodes (p <0.001), advanced stage of disease (p <0.001), extended operation duration (>150 min; p <0.001), higher operative bleeding volume (>200 ml; p <0.001), postoperative transfusion, preoperative serum fibrinogen levels, CEA levels and CA 19-9 levels (p <0.001). Multivariate analysis indicated that the independent prognostic factors significantly associated with poor survival included non-radical lymph node dissection, palliative lymph node dissection, multi-organ involvement, advanced TNM stages, poor tumor differentiation, higher preoperative serum fibrinogen levelsand higher CA19-9 levels.Conclusions: Serum fibrinogen levels are positively correlated with advanced tumor stages and poor survival in GC patients undergoing gastrectomy. Preoperative plasma fibrinogen levels are an independent risk factor for survival in these patients. Serum fibrinogen is a useful biomarker for patients with clinically advanced GC. [ABSTRACT FROM AUTHOR]

We study the extinction time τ of the contact process started with full occupancy on finite trees of bounded degree. We show that, if the infection rate is larger than the critical rate for the contact process on Z , then, uniformly over all trees of degree bounded by a given number, the expectation of τ grows exponentially with the number of vertices. Additionally, for any increasing sequence of trees of bounded degree, τ divided by its expectation converges in distribution to the unitary exponential distribution. These results also hold if one considers a sequence of graphs having spanning trees with uniformly bounded degree, and provide the basis for powerful coarse-graining arguments. To demonstrate this, we consider the contact process on a random graph with vertex degrees following a power law. Improving a result of Chatterjee and Durrett (2009), we show that, for any non-zero infection rate, the extinction time for the contact process on this graph grows exponentially with the number of vertices. [ABSTRACT FROM AUTHOR]

Photoacoustic (PA) spectrum is a promising method in SF6 decomposition product detection. To develop an on-line monitoring device, a gas detection system based on PA effect was introduced. Three kinds of gases, SO2, CO2, and CF4, were chosen to test the device performance. Some experiments were conducted to get the relationship of PA signal and gas concentration. The minimum detection limit of each gas was also measured. After that, the influence of temperature on PA detection was studied under 30 °C−50 °C. It is found that the PA signals of SO2 (1360 cm ^-1 ), CO2 (2347 cm ^-1 ), and CF4 (1285 cm ^-1 ) all have negative temperature characteristics within that temperature range. Then, a temperature linear correction model was proposed. The maximum error between correction result and standard PA signal under reference temperature was <4%. The temperature correction method lays a foundation for manufacturing SF6 decomposition components on-line monitoring device. [ABSTRACT FROM PUBLISHER]

The oxidation of aluminium nanoparticles coupled with crystallisation of amorphous alumina shell is investigated through the thermogravimetric analyser and differential scanning calorimetry (TGA-DSC) and the transmission electron microscope (TEM). The thermogravimetric (TG) curves show stepwise shapes with temperature increase and could be divided into four stages. The reaction at the second stage is complex, including the simultaneous crystallisation of amorphous alumina (am-Al2O3) and Al oxidation. The crystallisation of am-Al2O3promotes the reaction through generating fast diffusion channels, like micro-cracks and grain boundaries in the oxide shell to accelerate the ionic diffusion. An enhancement factor (freact), which follows a power-law formula with the crystallisation rate, is introduced to quantify the impact of crystallisation on reaction. With heating rate increase, the second stage of TG curves shifts to the high temperature regime and the total weight gain at the second stage decreases slowly. A crystallisation-reaction model is constructed to fit and predict the weight gain after derivation of diffusivities and crystallisation kinetics. Modelling indicates that with heating rate rise, the mass increment at the second stage of TG curves decreases owing to the reduced reaction time, although the reaction is accelerated. The shift of TG curve to higher temperature is due to the polymorphic phase transition. Actually the derived kinetics of the crystallisation of amorphous alumina indicates that the polymorphic phase transformation mechanism works mainly below the heating rate of 3 K s–1. At higher heating rate, the melting of Al takes place firstly and the crystallisation of am-Al2O3follows to enhance the ionic diffusion. Therefore, when the heating rate is fast during ignition or combustion, the Al nanoparticles undergo both the melting of Al and the polymorphic phase transition of am-Al2O3to accelerate the reaction. [ABSTRACT FROM PUBLISHER]

We explored the thermal decomposition characteristics of SF6 with partial overthermal fault in organic solid insulating materials. Results show that when organic solid insulating materials were around the fault point, the main overthermal decomposition characteristic products of SF6 were CS2, CO2, CF4, H2S, SO2F2, SOF2, and SO2. The difference in the generating reaction and degree of reaction of the seven decomposition components resulted in the complexity of concentration and growth regularity. Surface component analysis after the experiment showed that the thermode surface contained numerous S, O, C and F. Fe existed in the form of Fe2O3 and FeF2. The organic insulating materials added new elements, such as F and S, because HF and H2S easily reacted with O in the epoxy group. [ABSTRACT FROM AUTHOR]

The environmental impacts of grid-connected photovoltaic (PV) power generation from crystalline silicon (c-Si) solar modules in China have been investigated using life cycle assessment (LCA). The life cycle inventory was first analyzed. Then the energy consumption and greenhouse gas (GHG) emission during every process were estimated in detail, and finally the life-cycle value was calculated. The results showed that the energy payback time ( T EPBT ) of grid-connected PV power with crystalline silicon solar modules ranges from 1.6 to 2.3 years, while the GHG emissions now range from 60.1 to 87.3 g-CO 2 ,eq/kW h depending on the installation methods. About 84% or even more of the total energy consumption and total GHG emission occupied during the PV manufacturing process. The solar grade silicon (SoG-Si) production is the most energy-consuming and GHG-emitting process, which accounts for more than 35% of the total energy consumption and the total GHG emission. The results presented in this study are expected to provide useful information to enact reasonable policies, development targets, as well as subsidies for PV technology in China. [ABSTRACT FROM AUTHOR]

Falling droplets significantly deform during the wet deposition and wet scrubbing processes, which affects particle capture. On the basis of studies on the deformation of droplets falling at terminal velocity with typical diameters, the flow and the temperature fields around deformed and spherical droplets were simulated by large eddy simulation. The deposition behavior of particles with varying diameters was studied in both flow processes. The effect of droplet deformation on the inertial capture efficiency and thermophoretic efficiency of particles was analyzed. Inertial capture efficiency is enhanced by droplet deformation when Stokes number ( St ) > 0.4 and reduced when St < 0.4. The relative difference in the inertial capture efficiencies of the deformed and spherical droplets with the same equivalent diameter increases first and then decreases and converges as St increases. The aforementioned phenomenon is a result of a change in windward area, the shield effects of the boundary layer, and particle inertia. Thermophoretic efficiency is reduced by droplet deformation, but the decrement is independent of temperature difference. The difference in thermophoretic efficiencies is a consequence of the shift in superficial area and in the Nusselt number caused by droplet deformation. A methodology to predict capture efficiency of deformed droplet is established based on comparing the capture efficiencies of deformed and spherical droplets. [ABSTRACT FROM AUTHOR]

Sulfur hexafluoride (SF₆) gas-insulated equipment (GIE) has been widely used in extra/ultra high voltage power transmission systems. During its operation, GIE inevitably experiences partial overthermal faults caused by poor contact. In this study, the SF₆ decomposition characteristic of partial overthermal faults was used to solve problems that cannot be detected effectively in GIE. First, a large number of experiments were conducted on an SF₆ overthermal decomposition system to obtain the overthermal decomposition characteristic of SF₆ below 400 °C. Then, from the perspective of the physical significance of engineering, three feature parameters, namely, total decomposition amount, effective formation rate, and ratio of characteristic components, were proposed to reveal the deterioration degree of the gas insulation medium as well as to represent the development trend and severity of a partial overthermal fault. Results show that total decomposition amount CT, CT1, and CT2 can depict the degradation degree of the GIE insulation medium and the carbonic metal structure caused by a partial overthermal fault, which can be a good index to differentiate partial overthermal fault temperatures. The effective formation rate of each characteristic component RRMS is closely related to temperature and can reflect the development trend of a partial overthermal fault. The feature ratio CO2/(SO₂F₂+SOF₄+SOF₂+SO₂+H2S) can reveal whether a partial overthermal fault involves organic insulation materials. H2S/(SO₂F₂+SOF₄) can depict the severity of a partial overthermal fault. Log10(SOF₂+SO₂)/(SO₂F₂+SOF₄) and its effective value TCRRMS3 can represent the deterioration degree of GIE and provide excellent correlation with the severity of a partial overthermal fault, and thus, it can be used to evaluate the severity of a partial overthermal fault quantitatively. [ABSTRACT FROM PUBLISHER]

Two Ce–Zr–La/Al2O3 composite oxides, CZLA-C and CZLA-B, were synthesized using a co-precipitation method in a continuous stirred-tank reactor (CSTR) and a batch reactor (BR), respectively. Two Rh-based three-way catalysts (TWCs), Rh/CZLA-C and Rh/CZLA-B were obtained by a wet-impregnation method using the two composites as the supports. The physicochemical properties of the samples before and after thermal treatment at 1000 °C were characterized by N2 adsorption–desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), H2-temperature programmed reduction (H2-TPR) and CO chemisorption. The results indicated that CZLA-C shows higher thermal stability than CZLA-B due to a sparsely-agglomerated morphology. Compared with Rh/CZLA-B, Rh/CZLA-C displayed better reducibility and higher thermal stability and exhibited significantly higher activity in the catalytic removal of the simulated gasoline vehicle exhaust emission (NO, CO and C3H8). Our work can provide a facile and economical synthesis route to advanced support materials and catalysts for exhaust emission control. [ABSTRACT FROM AUTHOR]

A disk-type two- and three-dimensional (2D, 3D) X-ray dose imaging detector was developed based on the radiation-induced silver (Ag)-related species in Ag-activated phosphate glass. This luminescent detector is based on the blue and orange radiophotoluminescence (RPL) phenomena. A comparative study of the steady- and transient-state optical properties of blue and orange RPL, such as the time-resolved luminescence spectra and the RPL decay curves, was performed. In addition, the combination of a confocal optical detection system with a transparent glass detector enables 3D reconstruction through the stacking of dose images collected at different depths within the material. The capabilities of this detector for 2D and 3D dose imaging applications are discussed. [ABSTRACT FROM AUTHOR]

The reaction between NO and biomass volatiles is important during biomass reburning deNOx technology. NO reduction by the simulated biomass volatiles (CH 4 , CO, H 2 , and CO 2 ) was studied by experiments and kinetic modeling. The effect of inherent K/Na release on NO reduction by biomass volatiles was also studied. Results showed that the primary constituent in NO reduction was CH 4 , and NO reduction by other constituents in biomass volatiles alone was negligible at the same conditions. There existed an interaction between the constituents during NO reduction, which reduced the optimum excess air coefficient ( λ ) to 0.6 at T = 1300 K, and the optimum temperature to 1200 K at λ = 0.7. The synergetic deNOx effect was caused by CH 4 and H 2 , whereas CO has little effect. Kinetic analysis indicated that H 2 promoted CH 4 oxidation and CH 3 generation by enhancing the concentrations of H, O, and OH, and then promoted NO reduction. The influence of alkali released from biomass on NO reduction by multi-constituent biomass volatiles was different from on NO reduction by CH 4 . At 1300 K, when λ < 0.55, K/Na could improve NO reduction by biomass volatiles, and when λ > 0.55, K/Na could not improve and even inhibited NO reduction by biomass volatiles. Hydroxide was better than chloride in improving NO reduction. K and Na affected NO reduction by biomass volatiles through enhancing active species, which was similar to the effect of H 2 . The trade-off between K/Na and H 2 made the deNOx performance of biomass volatiles different from that of CH 4 . [ABSTRACT FROM AUTHOR]

In this work, the pulverized coal combustion of Zhundong lignite was conducted in an optically-accessible, downward Hencken flat-flame burner to investigate the incipient formation of ultrafine particulate matter (PM). The ultrafine PM were collected in - flame from distinct positions under 1800 K, 1500 K and 1200 K using a self-designed thermophoretic sampler, together with extensive conventional transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDS) examinations. A novel in situ low-intensity phase-selective laser-induced breakdown spectroscopy (PS-LIBS) was further introduced to diagnose the dynamic behavior of particle-phase sodium during the pulverized coal combustion. The primary particles in the collected ultrafine PM have mean diameter of 8–15 nm, with Si and Na as main mineral components based on TEM/HRTEM–EDS results. The formation of ultrafine PM is regarded as a process of multi-component flame syntheses of mineral precursors, in which the competition between the devolatilization and the coalescence of particles are of most significance. Finally, based on an approach of time scale analysis, three characteristic times of minimum mean diameter of primary particles, the initial increment point of particle-phase sodium and the maximum devolatilization are found to be highly correlated. [ABSTRACT FROM AUTHOR]

Background: Intravenous iron sucrose and oral iron therapy are the main therapies for iron deficiency anaemia (IDA), but there is still a debate regarding their efficacy and especially as to which one is the best choice during pregnancy.Methods: A meta-analysis of randomised controlled trials comparing patients treated with intravenous iron sucrose (intravenous group) with those treated with oral iron (oral group) for IDA during pregnancy was performed. The primary outcomes of interest were mean maternal haemoglobin and serum ferritin levels at the end of treatment. Secondary outcomes were treatment-related adverse events and foetal birth weight.Results: Six randomised controlled trials, involving a total of 576 women, were included in the present review. Significant increases in haemoglobin [mean difference (MD), 0.85; 95% confidence interval (CI), 0.31-1.39; p = 0.002] and ferritin levels (MD, 63.32; 95% CI, 39.46-87.18; p < 0.00001) were observed in the intravenous group. Compared with the oral group, there were fewer adverse events in the intravenous group (risk ratio, 0.50; 95% CI, 0.34-0.73; p = 0.0003). There was no significant difference in birth weight between the two groups.Conclusion: For pregnant women who could not tolerate the side effects of oral treatment or required a rapid replacement of iron stores, intravenous iron sucrose was associated with fewer adverse events and was more effective than regular oral iron therapy. [ABSTRACT FROM AUTHOR]

In this study, Al 2 O 3 , ZrO 2 , La 2 O 3 , and Y 2 O 3 were separately introduced into Pt/CeO 2 -MnO x catalyst to improve the thermal stability of catalysts and obtain a better soot and NO oxidation activity after thermal treatment. CeO 2 -MnO x -RO x (R = Al, La, Y, or Zr) mixed oxides were prepared by a co-precipitation method. The catalysts were characterized by XRD, BET, H 2 -TPR, CO chemisorption, XPS, TG analysis, soot–TPO, and NO–TPO. It is found that the introduction of R n + into CeO 2 -MnO x markedly increases the thermal stability of the catalysts for soot and NO oxidation, remaining a better catalytic oxidation activity. On the one hand, after high-temperature aging, for the modified catalyst Pt/CeMnRO x , the ignition temperature of soot oxidation ( T i ) and maximal soot oxidation rate temperature ( T m ) increase by 30–50 °C and 4–32 °C, respectively, whereas Al 3 + -modified catalyst shows the best thermal stability. On the other hand, due to a key role of NO 2 as a strong oxidizing agent in soot oxidation process, the NO oxidation activity is often considered as an important aspect. This work shows that R n + -modified catalysts display a better stability on NO oxidation activity after aging. Some factors leading to the thermal deactivation of catalysts are also discussed in this paper. [ABSTRACT FROM AUTHOR]

The projected warming trend in the 21st century is likely to alter the global distribution of mangroves. However, the migratory pattern of different mangrove species is still unclear, especially in the subtropical Brazilian littoral. This study utilizes pollen, diatom, and organic geochemistry to document the late Holocene morphological and ecological transformation in São Francisco do Sul Bay, the mangrove sub-range limit in south Brazil. This multi-proxy dataset indicates the establishment of saltmarshes and mangroves on muddy tidal flats at ∼1720 and ∼870 cal yr BP, and Laguncularia , Avicennia , and Rhizophora colonized the study area at ∼870, ∼390, and ∼70 cal yr BP, respectively. This stepwise succession of three mangrove species in São Francisco do Sul Bay, and poleward mangrove expansion toward the austral mangrove range limit, indicate that the migratory histories of different mangrove species were not synchronized during the late Holocene, and temperature is the primary climatic factor regulating the mangrove distribution in south Brazil. More importantly, the Medieval Climate Anomaly and the Current Warm Period were clearly registered in the pollen record, suggesting that the two climate anomalies likely facilitated the mangroves colonization into higher latitudes in south Brazil. Overall, our dataset indicates that mangrove expansion into more temperate zones will likely accelerate in South America. [Display omitted] • Temperature is the primary climatic factor regulating the mangrove distribution in South America. • Medieval Climate Anomaly and the Current Warm Period likely facilitated the poleward mangrove migration in south Brazil. • The migratory histories of different mangrove species in South America were not synchronized during the late Holocene. [ABSTRACT FROM AUTHOR]

• The addition of ion-exchangeable calcium reduces the soot mass yield during coal pyrolysis. • Ion-exchangeable calcium decreases the sizes of soot primary particles and soot aggregates. • Calcium loading shrinks the disordered cores of soot, promotes the soot graphitization, and leads to more compact aggregates. • The size distributions of inorganic species show that calcium and sodium play different roles in soot formation. This work investigated the effect of ion-exchangeable calcium on the mass yield, size distribution and structural properties of carbonaceous particulate matter from coal pyrolysis. The raw, acid washed and calcium-exchanged coal samples were pyrolyzed in a flat-flame burner at 1600 K. The particulate matter was collected with a three-stage dilution sampler. Then, the particle size distributions were measured by a low pressure impactor (DLPI+) and a scan mobility particle sizer (SMPS). The results show that, with the addition of ion-exchangeable calcium, the soot yield reduces, and the size growth of soot particles is inhibited. Transmission electron microscopy (TEM) analysis shows that ion-exchangeable calcium diminishes the sizes of disordered cores in soot primary particles, accelerates the graphitization of soot and makes the soot aggregates more compact. The chemical structures derived from Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR) indicate that the graphitization degree of the soot is first enhanced and then inhibited with increasing calcium loading amount. Additionally, the inorganic species in the size-segregated soot particles were characterized. The fractions of calcium and sodium in soot show opposite trend with particle size. Unlike Na, which nucleates before soot inception, Ca tends to participate in both the soot nucleation and surface growth processes, and is enriched at larger particle size. [ABSTRACT FROM AUTHOR]

To explore the influence mechanism of trace H2O on SF6 decomposition characteristics under partial thermal fault and establish the foundation of using SF6 thermal decomposition principle to diagnose the thermal fault of SF6 electrical equipment, a series of artificial thermal fault decomposition experiments with different H2O concentrations were conducted on the designed SF6 thermal decomposition experimental system. A trace water injector was used to control the content of trace H2O accurately and gas chromatograph, chromatography-mass spectrometry as well as Fourier transform infrared spectroscopy were used to measure decomposed components. Finally, the thermal decomposition characteristic under 340 ° was achieved. The analysis results indicate no matter how much H2O content is, SF6 can decomposes into many kinds of decomposition characteristics, such as CO2, SOF2, SO2, SOF4, SO2F2, H2S, HF. The concentrations of all these decomposition characteristics increase with the time extended, but change differently with the increase of H2O content, because H2O plays different role in the formation process of each decomposition characteristic components. The variation of H2O content not only affects the production of the decomposition characteristic components, but also makes SO2 and HF gradually evolved into the main characteristic components of SF6 thermal decomposition. In addition, the higher the H2O content is, the stronger the promoting effect on SO2 and HF is. [ABSTRACT FROM AUTHOR]

The high-reserve Zhundong lignite, rich in Alkali and Alkaline Earth Metal (AAEM) elements, causes severe fouling and slagging problems in stationary combustion systems. In this paper, the ash deposition propensity as well as its relation to AAEM-rich fine particulates was investigated in a 25 kW down-fired furnace possessing similar conditions to practical combustors. The high content AAEM (mainly calcium) species in Zhundong lignite results in the molten slag at the vicinity of the burner inlet, differing from other case burning high-ash-fusion (HAF) bituminous coal. The ash deposits were collected at a position with gas temperature of 800 °C, whereas the fine particulates were sampled at the same position by a two-stage nitrogen-dilution isokinetic probe. The deposition tendency of ash particles from Zhundong lignite is apparently higher than those from contrast fuels and even herbaceous biomass. It is then related to the sticky surfaces of both bare deposition tube and bulk fly ash particles, forming from large amounts of AAEM species, which enhances the deposition propensity. [ABSTRACT FROM AUTHOR]

The interactions between high density polyethylene (HDPE) and potato during their primary and secondary co-pyrolysis process were investigated by a thermogravimetric analyzer (TGA) and a tubular furnace. Kinetic analysis has shown that the devolatilization of potato was relatively faster compared to those of cellulosic materials, which has been ascribed to the multi-side-chain structure and lower polymerization degree of starch. The pyrolysis process of potato can be divided into three stages, and the main thermal degradation took place between 178 and 378 °C, while the HDPE decomposition occurred in a single stage in the temperature range of 380–517 °C. In the case of blends, the weight loss differences (Δ W ) between experimental and theoretical ones were less than ±8% in all cases, and the co-pyrolysis process of potato and HDPE can be described as two consecutive first order reactions, the apparent activation energies of blends were almost invariable, suggested that only physical step limitation was found in the primary co-pyrolysis process of potato and HDPE. On the contrary, the results of tubular furnace experiment showed that due to the relatively long gas resident time, the interaction occurred in the gas phase not only favored the formation of gaseous products, but also improved the bio-oil quality by significantly reducing the oxygen-to-carbon ratios (O/C) of the pyrolysis oil. [ABSTRACT FROM AUTHOR]

The temporal release of K from single pinewood particles of four different initial masses (20–50 mg) in a Hencken burner was measured in-situ by laser-induced break down spectroscopy (LIBS). Particle temperature during the combustion was measured by two-color pyrometry. A calculation method was developed to determine the K release flux across the plume based on LIBS measurement and computational fluid dynamics (CFD) model. For all the 4 particle sizes, the temporal release rate of K showed a peak during devolatilization, a monotonous increase during char combustion and a monotonous decrease during the ash stage. It is found that the cumulative fraction of released K was below 4% in the devolatilization stage and ∼20% in the char combustion stage. The particle mass did not have significant influence on the K release. The mechanism of the K release during the char combustion was analyzed, based on the initial portioning of K as inorganic K and organically-bound Char-K. The inorganic K releases mainly by thermal decomposition. The Char-K releases mainly by converting first to inorganic K when the char is burnt and then by releasing to gas phase from the inorganic K. A kinetic model for the release of K during pinewood char combustion was developed on this basis. The kinetic parameters for the release of K was found to be influenced by the initial partitioning between the inorganic K and the Char-K. The correlated initial proportion of inorganic K in pinewood char was found to be 0.37, while the correlated pre-exponential factor and the activation energy for K release were 12.5 1/s and 89.9 kJ/mol, respectively. [ABSTRACT FROM AUTHOR]

SF6 decomposition characteristics under partial discharge (PD) are not only associated with insulation fault type and its severity but also closely related to the H2O content of in the equipment. This paper studies the decomposition characteristics of mixture gas SF6/H2O with six different gradients of trace H2O under the same PD energy, selects SO2F2, SOF2, CO2, and CF4 as the characteristic components, and analyzes the influence regularity of trace H2O on each of the component concentration, effective formation rate and characteristic ratio. Results show that H2O creates favorable conditions for generating SO2F2 and SOF2 owing to the capacity to capture F atom and inhibit low fluorine sulfides from recombining into SF6. As a result, the concentration and effective formation rate of SO2F2 and SOF2is positively related with H2O. Whereas H2O has no evident influence on CO2, it can consume intermediate by-products CF2 and CF3 which restrain CF4 generation. Each characteristic ratio decreases sharply and then becomes stable with increment of H2O. The defined effective characteristic ratio effectively reflects its relationship with H2O, whereas obtained mathematical expression between each effective characteristic ratio and trace H2O lays solid foundation for fault diagnosis of SF6 insulated equipment based on SF62 decomposition characteristics. [ABSTRACT FROM AUTHOR]

Highlights: [•] CaO catalyzes NH3 decomposition, NO reduction by NH3, and NH3 oxidation by O2. [•] NH3 dissociation to NH2 is the rate-controlling step of NH3 conversion. [•] NH3 conversion on the CaO surface is mainly influenced by O2. [•] The selectivity of NH3 conversion is influenced by both O2 and NO. [•] Mechanism and kinetic model are proposed to describe the CaO-involved SNCR process. [ABSTRACT FROM AUTHOR]

To obtain the influence regularity of trace O2 on SF6 decomposition characteristics under partial discharge (PD) and establish the foundation of using SF6 decomposed components to diagnose the insulation status of SF6 electrical equipment, first, a series of PD decomposition experiments with different O2 concentrations (%)were conducted on a special experiment platform. The variation regularity between the concentrations of characteristic components and the different content of O2 were obtained quantitatively. Second, the correlation coefficient r testing method was applied to identify the associated influence of trace O2 on the decomposed characteristic components and characteristic ratios. Based on this, an exponential regression model of the related characteristics was developed. Finally, the influence mechanism of trace O2 on SF6 decomposition progress was explained reasonably. The results show that under the PD caused by metal protrusion insulation fault without organic solid insulated materials, CO2, SO2F2, and SOF2 were the mainly decomposed components in the specific range of trace O2. Although no obvious influences of the trace O2 on the concentrations of CO2 and SOF2 as well as the ratio c(CO2)/c(SO2F2+SOF2), it is notable that the trace O2 is negatively and positively related to the concentration of SO2F2 and the ratio c(SOF2)/c(SO2F2), respectively. The exponential regression model can minimize the effect of trace O2 on the fault diagnostic result when using SF6 decomposed components. [ABSTRACT FROM AUTHOR]