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Oil-in-water (O/W) emulsion droplet formation in a co-flowing capillary device was observed through experiments and simulated by using the volume-of-fluid/continuum-surface-force (VOF/CSF) method. Two flow regimes in droplet formation, namely dripping and jetting, were observed in the experiment and perfectly simulated by the numerical method. Further the effects of two phase flow rates, viscosities, interfacial tension, and wall effect as well as the wetting property of capillary surface on the droplet forming process were extensively investigated by numerical simulation. It is found that the droplet diameter mainly depends on the flow rate and viscosity of the continuous phase and the interfacial tension. With increasing the flow rate and viscosity of the continuous phase or decreasing the interfacial tension, the droplet diameter decreases. Based on the experimental and simulated results, a correlation of dimensionless droplet diameter with the Capillary number, Reynolds number and a wall effect factor was presented for the dripping regime in different-sized devices. Finally the transition from dripping to jetting flow regime was studied. The results indicate that the Capillary number of the dispersed phase (Cad) plays a significant role in this transition. When Cad exceeds about 0.3, the transition from dripping to jetting regime occurs. These study results can provide a useful guide for the preparation of monodisperse droplet with controllable size by using the co-flowing microfluidic device.

Drying is one of the most important processes to prepare the hollow polystyrene (PS) shells which meet the requirements for the inertial confined fusion experiments. A tracing experiment was taken by white light interferometer to explore the drying process. The results indicate that the inner water drop passed through the PS shells with the state of water stream molecule. During the experiment, three structures were observed by digital microscope: the structure of craze, mixture of craze and cracks, and cracks. With ongoing drying, the decrease in the interfacial energy was regarded as the inducing factor for the formation of craze, while the residual stress inside the PS shells was the primary cause. Once the craze formed, it not only reduced the strength of the PS shells but also served as the stress concentration point. In the function of adequate time and stress, the voids of craze would coalesce resulting in the cracks formation. High-temperature treatment to the PS shells at 75°C for 3 h was...

Interleukin-32 (IL-32) is a newly discovered proinflammatory cytokine. However, there are limited data regarding IL-32 as a biomarker for heart failure (HF). In this study, we assessed the prognostic value of IL-32 in patients with chronic HF after myocardial infarction (MI).Over a period of 1.8years, we prospectively enrolled 100 patients with chronic HF after MI. IL-32, NT-proBNP, Matrix metallopeptidase 9 (MMP-9), procollagen type I (PI) and type III (PIII) were measured at baseline. Study endpoint was adverse cardiac events. High IL-32 levels were associated with numerous factors that are related to deteriorate cardiac function and cardiac fibrosis. Strong expression of IL-32 was detected in human cardiomyocytes from HF tissue. ROC curve revealed the area under the curve of IL-32 for predicting negative outcome of HF was 0.72 (95% CI: 0.60-0.83, P0.01). Kaplan-Meier statistics showed that the risk of adverse cardiac event was 5.75 fold (hazard ratio 5.75, 95% CI 1.53-21.58, P=0.009), which increased in the highest quartile (296pg/mL). Cox regression analysis revealed IL-32 was an independent predictor for cardiac events (hazard ratio 2.78, 95% CI 1.02-7.57, P=0.046). Recombinant IL-32 significantly exacerbated infarct size in a mouse model of MI. IL-32 upregulated expression of MMP-9, PIII and transforming growth factor beta in rat fibroblasts.IL-32 might be a novel predictor of adverse cardiac event in patients with HF after MI. The pro-fibrotic effect of IL-32 may contribute to adverse cardiac remodeling and progression to HF.

BackgroundThe associations between anemia and household water source and sanitation remain unclear.ObjectivesWe aimed to assess the associations between anemia and household water source or sanitation in preschool children (PSC; age 6-59 mo) using population-based surveys from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project.MethodsWe analyzed national and subnational data from 21 surveys, representing 19 countries (n = 35,963). Observations with hemoglobin (Hb) and ≥1 variable reflecting household water source or sanitation were included. Anemia was defined as an altitude-adjusted Hb concentration

Background:Bronchiectasis is a known extra-articular manifestation of rheumatoid arthritis (RA) and can lead to decreased quality of life as well as increased risk for infection and mortality. Understanding the burden of bronchiectasis in RA may lead to a better understanding of pathogenesis and improved management. We performed a systematic review and meta-analysis to determine the prevalence of bronchiectasis in RA.Objectives:We investigated the prevalence of RA-related bronchiectasis (RA-BR) using a systematic review and meta-analysis.Methods:We followed the PRISMA-P 2015 guideline for systematic reviews and registered this analysis (ID#199080) on PROSPERO. We queried PubMed and EMBASE databases using the search strategy “rheumatoid arthritis; AND; bronchiectasis” as of July 31, 2020. The inclusion and exclusion criteria were assessed for study eligibility by two independent abstractors. Exclusion criteria included: (1) non-primary literature (i.e., review articles, editorials); (2) case reports involving less than 5 patients; (3) published in a language other than English; (4) did not relate to both RA and bronchiectasis; and (5) studies not involving humans (e.g., mouse models). After the initial screen, we conducted a full text review to verify that inclusion criteria were met: (1) reported frequency of RA-BR and denominator of all RA patients in the study sample. Data including type of study design, method of RA-BR detection, and RA characteristics were extracted by two independent abstractors. We performed meta-analyses using random effects models to estimate prevalence of RA-BR among RA overall and restricted to retrospective or prospective studies.Results:Out of a total of 208 studies, 37 studies were identified that reported frequency of RA-BR among RA. The included studies had heterogeneous methods to identify RA-BR that were based on either clinical or research chest computed tomography (CT) imaging and had varying methods to adjudicate images. Some studies focused on patients with respiratory symptoms or suspected RA-associated interstitial lung disease (RA-ILD). There were a total of 8,646 patients with RA, and 612 were identified as having RA-BR. The pooled overall prevalence of RA-BR in the random effects meta-analysis was 18.2% (95%CI 13.3-23.7%, Figure 1). Among prospective studies (n=24), the prevalence of RA-BR in the meta-analysis was 20.7% (95% CI 14.7-27.4%). Among retrospective studies (n=13) reporting RA-BR, the prevalence was 14.5% (95% CI 7.2-23.7%). Prevalence was lowest in retrospective studies where RA-BR was identified through clinical care (e.g., two large retrospective studies that investigated 4,000 and 1,129 RA patients reported RA-BR prevalence of 0.6% and 2.7%, respectively). The two largest prospective studies that incorporated a research protocol performing chest CT imaging on all enrolled patients investigated 150 and 332 patients with RA and reported a RA-BR prevalence of 8.0% and 9.6%, respectively. Smaller studies of both study design types generally reported higher prevalence of RA-BR.Figure 1.Pooled prevalence of RA-related bronchiectasis in RA among all studies identified (n=37).Conclusion:The prevalence of RA-BR in this systematic review and meta-analysis was 18.2%, emphasizing that bronchiectasis is a common extra-articular feature of RA. However, some studies may have identified subclinical RA-BR through research imaging or RA-BR may have been secondary to RA-ILD. Future studies should standardize methods to identify RA-BR cases and investigate the natural history and clinical course given the relatively high prevalence that we report.Disclosure of Interests:Lily Martin: None declared, Lauren Prisco: None declared, Weixing Huang: None declared, Gregory McDermott: None declared, Nancy Shadick Consultant of: Consultant < 5K Bristol-Myers Squibb, Grant/research support from: BMS Amgen Lilly, Mallinckrodt, and Sanofi, Tracy Doyle Consultant of: Boehringer Ingelheim (

Minimum ignition temperature of dust clouds (MITC) was studied experimentally and theoretically in different atmospheres. Three carbonaceous dusts were tested in both air and O2/CO2 atmospheres with CH4 mole fraction from 0% to 2%. Results showed that the ignition risk of the three dusts significantly increases (decrease of MITC by ~100 ℃) with increasing XO2 from 21% to 50%, but significantly decreases replacing N2 in air with CO2. The inhibition effect of CO2 on MITCs could be diminished by increasing XO2 or adding CH4. The addition of small amount of CH4 has different effects on the MITCs of different dust samples, following the opposite order of volatile matter content: anthracite>bituminous coal>starch. Two modified steady-state ignition models, considering the density of mixture gas and dust cloud, XO2 and its diffusivity, were developed to interpret the experimental observations. The analysis revealed that the global heterogeneous ignition model suits well for the hybrid mixtures of anthracite or bituminous coal dusts. In contrast, the proposed global homogeneous ignition model was found to be only valid for the pure starch dust, and the extra CH4 addition could strongly affect the ignition process of starch, particularly in O2/CO2 atmospheres with higher XO2.

Effects of fluid property on the formation of millimeter-scale compound droplets in a co-flowing device were systematically investigated via a simulation method using the VOF-CSF model. The simulation shows that compound droplets are formed in three regimes, namely, dripping regime, transition regime, and jetting regime. Increasing the flow rate or viscosity of outer fluid cause flow regime to convert from dripping to jetting, and the diameter of droplet significantly decreases. However the effects of inner fluid viscosity on formation dynamics always appear various, where the breakup mode of core droplet can be significantly changed, but the influences on its geometric dimensions can be ignored. In addition, the effects of internal and external interface tension are also further discussed. Finally, a dimensionless number ξ is proposed to predict the flow regimes of compound droplets formation. The results could provide theoretical guidance for controllably preparing monodisperse millimeter-scale compound droplets with specific size.

A novel technical solution about helically coiled tube-in-tube (HCTT) heat exchanger with double cooling source is proposed to obtain regeneratively cooled air for advance aeroengine. 54 simulation runs are performed according the Box-Behnken design table, in which the effect of geometrical and operating parameters on performance of heat exchanger are well considered. Grid independence was carefully carried out referring to ASME VV the regression models have a good prediction performance; outer tube curvature ratio (δo) is the most significant structure parameter affecting Ne and Ta,out, while inner tube curvature ratio (δi) is the most significant linear term for predicting η, indicating that δo and δi are key structure parameters. It also shows that heat transfer characteristics of the HCTT heat exchanger are complicated engineering problem subjected to multi factors interaction. For instance, total number of terms in model for predicting η reaches to 18, including 5 linear terms, 10 interaction terms along with 3 square terms. The influences of all interaction terms on Ne, η, and Ta,out were displayed using 3D surface graph, the effect rule of interaction terms were discussed in details. Desirability function approach was employed to conduct multi-objective optimization for goals of Ta,out = 630 K, and minimum Ne and η. The optimum values of design variable were obtained. This method possesses practical significances for prediction and optimization of HCTT heat exchanger.

Gas–liquid concurrent downward flow through a new structured packing was investigated by experiment systematically. The experimental packing consisted of 21 sieve plates. Each plate was 190 mm×190 mm in side length and 1 mm in thickness. Three sets of packing with different sizes of sieve holes were tested. During experiment, four flow states have been observed, i.e., the trickling flow at low gas and liquid flux, the continuous flow at low gas but high liquid flux, the semi-dispersed flow at high gas flux and the completely dispersed flow as gas flux increases further. Another important phenomenon observed is the occurrence of pulsing flow, i.e., in some range of gas and liquid flow fluxes, both two phases will no longer flow smoothly through the sieve plates but flow downward in pulse regularly. Through extensive experiment, the rough boundaries for flow regime transition were obtained. Then, the pressure losses of gas flow and gas–liquid two phase flow in non-pulsing flow regime were systematically measured. The analysis for pressure differences measured at different locations show that for a given packing, the pressure loss through each plate is nearly the same. Its magnitude depends on the gas and liquid flow rates. The comparisons between pressure losses of different packings indicate that the pressure loss is associated with the hole diameter, hole pitch, free area ratio of sieve plate and the mounting distance between two adjacent plates. Finally, considering these factors, the correlations for pressure drops were developed, which approximates the experimental values with an average deviation less than 10%.

Based on the analysis of multi-objective flexible job-shop scheduling problem (FJSP), a multi-objective low-carbon job-shop scheduling problem(MLFJSP) with variable processing speed constraint is proposed in this paper. The optimization objectives of MLFJSP include minimizing the makespan, total carbon emission and machine loading. Meanwhile, an improved artificial bee colony algorithm (IABC) is designed to solve the MLFJSP. The improvement of algorithm mainly includes: (1) an effective three-dimensions encoding/decoding mechanism and a mixed initialization strategy are designed to generate a better initial population; (2) special crossover operators and mutation operators were designed to increase the diversity of the population in the employed bee phase; (3)an efficient dynamic neighbor search (DNS) is applied to enhance local search capabilities in the onlooker bee phase; (4) the new food sources generation strategy was proposed to reduce the blindness in the scout bee phase. Finally, this paper carried out a series of comparative experimental studies, including the comparison before and after algorithm improvement, and the comparison between the improved algorithm with MOPSO, MODE and NSGA-II. The results demonstrate that the IABC can achieve a better performance for solving the MLFJSP.

In this study, a SPICE model for negative capacitance vertical nanowire field-effect-transistor (NC VNW-FET) based on BSIM-CMG model and Landau-Khalatnikov (LK) equation was presented. Suffering from the limitation of short gate length there is lack of controllable and integrative structures for high performance NC VNW-FETs. A new kind of structure was proposed for NC VNW-FETs at sub-3nm node. Moreover, in order to understand and improve NC VNW-FETs, the S-shaped polarization-voltage curve (S-curve) was divided into four regions and some new design rules were proposed. By using the SPICE model, device-circuit co-optimization was implemented. The co-design of gate work function (WF) and NC was investigated. A ring oscillator was simulated to analyze the circuit energy-delay, and it shown that significant energy reduction, up to 88%, at iso-delay for NC VNW-FETs at low supply voltage can be achieved. This study gives a credible method to analysis the performance of NC based devices and circuits and reveals the potential of NC VNW-FETs in low-power applications.

Since the last century, the challenges caused by fire prevention of cabin and cargo compartment materials were increased year by year. As one of main part for cabin and cargo compartment materials, the flame penetration resistance ability of cargo liners was become a research focus. However, the 45 degree combustion test and oil burner test (which were used to test flame penetration resistance ability of the cargo liners) are quite similar in experimental scale and experimental conditions, which can cause great trouble for the research of the flame penetration resistance ability of cargo liners. Thus, the differences between 45 degree combustion test and oil burner test were discussed in this paper.

Godbert-Greenwald furnace was used to investigate the minimum ignition temperature of dust clouds (MITC) in air with the presence of flammable gas which is lower than its lower explosion limit (LEL). Three flammable gases (CH4, H2 and CO) and three carbonaceous dusts (anthracite coal, bituminous coal and sweet potato starch) were tested. Results showed that all flammable gases have distinct effects on the MITC of the dust samples and volatile matter content of dust plays an important role during the ignition process. Specifically, the MITC of anthracite coal dust decreased from 610 °C to 560 °C, 580 °C and 570 °C with 3% CH4, 3% CO and 2.5% H2, respectively. Moreover, a heterogeneous ignition mechanism model was proposed to verify the equally global ignition characteristic between hybrid anthracite coal-CxHy mixture and bituminous coal. All three gases had an ignorable effect on the MITC of starch dust considering the experimental error. The presence of CO and H2 slightly promoted the ignition of bituminous coal dust, but the addition of CH4 showed a distinct concentration effect on the MITC of bituminous coal: the MITC decreased with 1% CH4 while increased with 2% and 3% CH4. This negative-effect of flammable gases at such low concentrations on ignition temperature of bituminous coal dusts was found for the first time. Furthermore, the presence of the 2nd flammable gas had a smaller effect on the MITC of dust samples with a higher volatile content, resulted from the competition of heterogeneous and homogeneous ignition mechanisms.

A 20-L spherical explosion chamber was used to investigate the minimum explosion concentration (MEC) of coal dusts with small amount of flammable gas which is lower than its lower explosion limit (LEL). Two dust samples (anthracite coal and bituminous coal) and three flammable gases (CH4, H2 and CO) were tested. Two methods respectively based on overpressure and combustion duration time were used to determine the MEC of the hybrid mixtures. Experimental results show that the explosion of hybrid mixtures occurs when both dust and gas concentrations are lower than the LEL or MEC of the single substances. As flammable gas concentration increases, either explosion pressure (Pex) and explosion pressure rise (dp/dt)ex) increase or the MEC decreases for all the hybrid gas-dust mixtures as a general trend, showing a strong concentration effect. At the same concentration of coal dusts, the addition of CH4 poses a higher explosion risk than the other two flammable gases. Moreover, it was found that the results of MEC determined by both methods agree each other well, suggesting that both methods are valid to determine MEC of hybrid mixture in the synergic explosion region. The distribution of experimental data in the explosion regimes shows that the restricted areas defined by empirical formulas are insufficient from safety considerations.

To achieve the integrity of solid particles coated by water phase (S/W/O) compound droplets, it is important to investigate the transport process of the compound droplets in the horizontal straight channel. The experimental results show that the integrity is significantly influenced by the flow rates and density difference. The water (W) phase is observed to be peeled off from the surface of the particles (polystyrene (PS) shells), mainly caused by the slip velocity of the W phase and the density mismatching among three phases. During the peeling off process, a relative motion between the solid (S) and W phases initially occurs, causing a decrease of the distance (δ) between them, and then, the PS shell is driven to pass through the W/O interface under the action of drag force and net gravity. It is also found that increasing flow rates of both phases contributes to obtaining integrated compound droplets. A boundary that separates the integrated from damaged compound droplets also exits when the fluid properties are fixed. Above the line of the boundary, compound droplets with integrity are prepared. Moreover, the absolute optimum density matching between the S and W phases is less than 0.003 g/cm3, while that between the W and oil (O) phases is less than 0.005 g/cm3.

Dust explosion severities are closely associated with dust dispersion behaviors. To characterize the dispersion process of dust cloud, visualization experiments were conducted by using a transparent Siwek 20-L chamber. Dispersion processes of typical carbonaceous dust were recorded by a high-speed camera and, with the image processing technique, the qualitative analysis based on the transmission of dust cloud was carried out. Results have evidenced the three consecutive stages of dust dispersion process: the fast injection stage of dust particles, the stabilization stage and the sedimentation stage of dust cloud. The motion of dust particles and the variations of dust cloud in space and time can be clearly distinguished. In the stabilization stage, the good uniformity of dust dispersion is achieved when the deviation of transmission data at different locations reaches to the minimum value. Under different nominal dust concentrations, the time periods for dust dispersion stabilization are found to be significantly different, suggesting that different dust concentrations should correspond to different ignition delay in order to accurately measure the explosion characteristics in the Siwek 20-L chamber. Moreover, it is found that the decrease trend of transmission with increasing nominal dust concentration will become gradually leveling off, different from the inversely proportional relationship according to the Bouguer's law, and this indicates that the actual dust concentration will be lower than the nominal concentration or the dust cannot be fully dispersed at the case of high dust concentration. According to the experiment, when the nominal dust concentration exceeds to 1000 g/m3, the transmission will no longer vary visibly.

Explosion behaviors of coal dusts were systematically investigated to focus on the roles of moisture in dust explosion. It is found that, when the moisture content is lower, the explosion parameters (Pex, (dp/dt)ex and MEC) basically keep a linear relationship with the moisture content. With the further increase of moisture content, the moisture would gradually agglomerate fine particles by reducing inter-particle distance and forming liquid bridges between particles. This behavior causes the increase of effective particle size and the reduction of dust dispersibility, which would notably heighten the uncertainty of explosion tests. These results indicate that to limit the moisture content is necessary when measuring explosion parameters in practice. Considering that (dp/dt)ex is more sensitive than Pex and MEC to the particle agglomeration, for coal dusts with the particle size

The dust explosion behaviors induced by two different combustion mechanisms (homogeneous and heterogeneous mechanisms) were comparatively investigated, based on the experiments under different dust concentrations, particle sizes and initial pressures in Siwek 20-L chamber. Based on the thermo-gravimetric analysis (TGA), sweet potato dust and magnesium dust were selected as the representative dusts with homogeneous and heterogeneous combustion mechanisms, respectively. Experiments find that these two dusts have different behaviors in the explosion kinetics due to different combustion mechanisms. For sweet potato dust, the explosion pressure p max , the pressure rise rate (d p /d t ) max and the combustion fraction η exhibit similar variation trends as dust concentration increases and they all reach to the maximum values at the worst-case concentration; while for magnesium dust, the variation of (d p /d t ) max is somewhat different from that of p max , that is, the (d p /d t ) max will achieve the maximum at the concentration higher than the worst-case and keep stabilized with further increase of dust concentration. As the particle size decreases, the (d p /d t ) max for sweet potato dust will increasingly rise and gradually approach to a stabilized value, but for magnesium dust, the increase of (d p /d t ) max becomes pronounced only in the range of smaller particle sizes. To account the effect of initial pressure on p max under different combustion mechanisms, a dimensionless pressure P R was introduced to denote the relative intensity of explosion. It is found that, for sweet potato dust, the increased initial pressure will promote the explosion process (or with high P R ) for the dust cloud with high concentration due to the augmented oxygen concentration, but for the dust cloud with low concentration, the increased initial pressure will suppress the explosion process due to the increased resistance in devolatilization. For magnesium dust, the rise of initial pressure will generally promote the explosion process even for the dust cloud with low concentration; however, in the case of small particle size, the promotion of increased initial pressure to the explosion process is not so pronounced.

This paper considers the two-dimensional adhesive contact problem for a rigid insulating cylindrical punch acting on a gradient piezoelectric coating bonded to half-space.It is assumed that the material parameters of functionally gradient piezoelectric materials vary exponentially along the thickness direction.The adhesion between the punch and the contact surface of the coating is described according to the adhesion Model given by Maugis. By using the Fourier integral transform, the adhesive contact problem of gradient piezoelectric coatings is reduced to singular integral equations. the numerical method is applied to solve the singular integral equations with Cauthy kernel.The numerical results show that both non-homogeneous parameters of gradient piezoelectric material and adhesion effect have significiant impact on the adhesive contact behavior of gradient piezoelectric coating.

Explosion behaviors of typical light metal and carbonaceous dusts induced by different ignition energies were investigated based on systematic experiments in a Siwek 20 L vessel. Comparative analysis reveals that the explosion mechanism of carbonaceous dust is the volatile combustion, whereas the mechanism for light metal dust mainly features the surface heterogeneous oxidation. Influences of ignition energy on severity and flammability limit are much more significant for carbonaceous dust than light metal, especially for the powder with less volatile. An innovative approach was introduced to derive flame thickness from the pressure–time trace. The relation between explosion induction time and combustion duration of ignitor was also analyzed. Results show inappropriate ignition energy will cause under-/over-driving in the thermodynamic/kinetic characteristic measurements. In this way, a dimensionless parameter pressure ratio was introduced to evaluate the under-driving, while two methods by using flame thickness and induction time respectively, were proposed to evaluate over-driving. To improve the accuracy of dust explosion tests, authors advocate that explosion severity determination should be conducted at the critical ignition energy. Moreover, a comparison between the European and Chinese flammability limit determination procedures was also conducted, indicating that EN 14034-3 is suitable for light metal but not for carbonaceous, while GB/T 16425 appears to be slightly conservative for both carbonaceous and light metal dusts.

An integrated technology, consisting of solid–liquid separation, filtrate treatment, and solid mud reusing, is proposed based on a comparative analysis of existing methods. Systematic experiments with actual waste drilling mud were conducted. Initially, solid–liquid separation of the drilling mud was achieved by emulsion breaking with 80% H2SO4. The optimal filtration rate was gained when the operating pH and density were adjusted to 3 and 1.15 g/cm3, respectively. Then, Fenton oxidation was applied to the filtrate; for a maximum CODCr removal efficiency, the pH of the filtrate was found to be about 3–4, whereas the optimal dosage of [H2O2] was 0.55 and 0.0625 M, respectively. After being neutralized with CaO and aerobic digestion with active sludge, the removal efficiency of CODCr in filtrate exceeded 98%, leaving the CODCr less than 100 mg/L. Meanwhile, for solid mud reuse, different formulas were proposed for baking-free bricks. Test results indicated that, at a proper formula, the compressive...

The minimum explosible concentration (MEC) is a crucial parameter in dust explosion evaluation and prevention. The standardized method currently used to determine the MEC relies on the measurement of explosion pressure P m and the test results are strongly affected by dust dispersion behaviors. To investigate this effect, systematical experiments were performed for coal dust explosion in the Siwek 20-liter sphere. It is found that the measured values of P m are apparently dependent on the ignition delay time t ig because of the time-dependence of dust dispersion behaviors. For the dust with a given mass concentration and size distribution, there always exists an optimal ignition delay time t ig,opt at which the P m will reach its maximum value, P max , and a slight deviation of t ig from the t ig,opt may cause the measured P m to be obviously lower than the P max . To reliably determine the MEC, the t ig,opt should be adopted in the test, rather than the fixed t ig of 60 ms as prescribed by IEC, otherwise, the resultant MEC may be overestimated. Based on the analysis of flame propagation in dust cloud, an alternative method by using combustion duration time t com is proposed to determine the MEC. Analysis for experimental data shows that the values of MEC determined by using t com are basically consistent with those obtained by using P m at the t ig,opt , but less affected by the t ig , since the sensitivity of the t com to the t ig is much less than that of the P m .

Systematic experiments were carried out on explosions of coal dust-inertant mixtures. Explosion severity was gained by using Siwek 20 L vessel and factors strongly influencing inerting effectiveness, such as deflagration mechanism and inertant composition were taken into account. Tests of thermal-gravimetric analysis were conducted to identify the reaction mechanism of coal dust explosions. As a result, bituminous coal dust deflagrates via the homogeneous mechanism, while anthracite dust mainly features the mechanism of heterogeneous reaction. Results reveal that the inerting functional mechanisms are quite different for bituminous coal and anthracite dusts, and the homogeneous-combustion-dust is much easier to be inhibited than the heterogeneous-reaction-dust. Trends of higher inerting effectiveness are associated with better decomposability, more excellent performance of oxygen blocking. Moreover, the particular efficacy of free ammonia decomposed from monoammonium phosphate in flame extinguishing is identified. Added water shows the best inerting effectives due to particle aggregation induced by moisture, which gives the idea that humidification for coal dust is therefore a cost-effective approach for explosion prevention and mitigation.

To fabricate uniform hollow glass microspheres (HGMs) for application in hydrogen storage, a sol-microemulsion-gel process combined with a T-shaped junction microfluidic technology was developed to fabricate monosized precursor gel microspheres. Precursor gel microspheres with monodispersity index less than 4% can be obtained based on the uniform reactions in the monosized sol droplets as micro-reactors, with monodispersity index less than 3%, generated by the microfluidic device. The results show that the precursor gel microspheres have uniform diameter, density, microstructure, composition and high sphericity. The monosized dried gel microspheres can be transformed into uniform HGMs, with high yield and quality for hydrogen storage, in a high temperature vertical furnace under the optimized operating condition.

An experimental investigation was carried out on magnesium dust explosions. Tests of explosion severity, flammability limit and solid inerting were conducted thanks to the Siwek 20 L vessel and influences of dust concentration, particle size, ignition energy, initial pressure and added inertant were taken into account. That magnesium dust is more of an explosion hazard than coal dust is confirmed and quantified by contrastive investigation. The Chinese procedure GB/T 16425 is overly conservative for LEL determination while EN 14034-3 yields realistic LEL data. It is also suggested that 2000–5000 J is the most appropriate ignition energy to use in the LEL determination of magnesium dusts, using the 20 L vessel. It is essential to point out that the overdriving phenomenon usually occurs for carbonaceous and less volatile metal materials is not notable for magnesium dusts. Trends of faster burning velocity and more efficient and adiabatic flame propagation are associated with fuel-rich dust clouds, smaller particles and hyperbaric conditions. Moreover, Inerting effectiveness of CaCO 3 appears to be higher than KCl values on thermodynamics, whereas KCl represents higher effectiveness upon kinetics. Finer inertant shows better inerting effectiveness.

To investigate the variations of flavor substances in distillation process of Chinese Luzhou-flavor liquor, systematic experiments were carried out in an industrial-scale experimental distiller. Distillate samples were collected continuously throughout the whole distillation process and analyzed by gas chromatography and sensory evaluation. The results show that the compositions and variations of flavor substances mainly depend on their physical and chemical properties. The flavor substances with low boiling point, such as ethanol, acetaldehyde, ethyl format and ethyl acetate, are vaporized quickly and therefore have high contents in the distillate obtained in the early stage of distillation. The flavor substances with high boiling points enter into distillate mainly by extraction and, hence, their variations depend on the dissolving properties. The alcohol-soluble substances, such as ethyl hexanoate, ethyl butanoic and so on, are distilled out mainly in the early stage of distillation, and their extraction rates decrease as the distillation process proceeds, while the water-soluble substances, such as organic acids, ethyl lactate and so on, are mainly present in the latter-stage distillate and the extraction rates increase as the process proceeds. Variations of methanol and furfural were found irregular and the reasons for this irregularity were analyzed. Sensory quality of distillate declines as the distillation process proceeds. PRACTICAL APPLICATIONS Chinese liquor has been a traditional art continuing for thousands of years, but the distillation operation almost holds its way of ancient time and few studies about it have been conducted, so that the understanding of distillation process is largely limited to intuition. Variations of flavor substances during distillation process will certainly contribute to the understanding of distillation mechanism and the optimization of distillation operation. The remarkable differences of distillate qualities found in different distillation stages provide an experimental base for collecting liquors with different distillate qualities. The findings that the high quality distillate is produced in early distillation stage indicate the necessity to overcome the vapor-overflow phenomenon, which occurs usually in the early stage of distillation and causes a lot of loss of high quality liquor. Theoretically, this work will provide the experimental base and testifying data for the modeling of multicomponents mass transfer in liquor distillation process through a packed bed.

An experimental investigation was carried out on coal dust-inertant mixture explosions. Tests of explosion severity and flammability limit were conducted by using the Siwek 20 L vessel and influences of ignition energy, coal dust calorific value, coal dust concentration and inertant composition were taken into account. The increase of inerting results with ignition energy is followed by an approximate stabilization when ignition energy exceeds 5 kJ. The ignition energy region of 5–10 kJ is appropriate for inerting testing, whereas ignitors with energy lower than 5 kJ produce unrealistic inerting results. The inerting effectiveness of inertant increases with the reduction of coal dust calorific value. Coal dust concentrations near the stoichiometric concentration require the greatest amount of inertant to suppress explosions. As the coal dust concentration increases beyond the stoichiometric, the amount of inertant requirement is reduced. Due to the efficient decomposition and particular flame extinguishing mechanism, monoammonium phosphate represents more excellent inerting effectiveness than calcium carbonate.

Double-shelled CeO2 hollow microspheres (4–5 µm) were synthesized through a facile one-step hydrothermal treatment of Ce(NO3)3·6H2O in the presence of citric acid and hexamethylenetetramine (HMTA),...

The influence of distributor structure on solids distribution is studied in two riser circulating fluidized bed reactors with different distributor structures but similar diameters. Optic fibre probes were used for the measurement of local solids distribution. The axial and radial distribution of solids holdup in the riser with a multi-tube distributor is more uniform than that with a multi-orifice distributor. The radial profiles of particle velocity in the riser with the multi-tube distributor are also more uniform than that with the multi-orifice distributor. In the riser with the multi-tube distributor, both gas and particles are distributed more uniformly across the section, so that the flow acceleration is much more uniform and faster. The flow development is much faster and the fully developed region is reached early for the riser with the multi-tube distributor. The distributor design is an important factor for the design of circulating fluidized bed reactor. L'influence de la structure du distributeur sur la distribution de solides est etudiee dans deux reacteurs a lit fluidise circulant a colonne montante avec differentes structures de distributeur mais des diametres similaires. On a utilise des sondes a fibres optiques pour mesurer la distribution de solides locaux. La distribution axiale et radiale de la retention de solides dans la colonne montante avec un distributeur a tubes multiples est plus uniforme que celle d'un distributeur a orifices multiples. Les profils radiaux de la vitesse des particules dans la colonne montante avec le distributeur a tubes multiples sont egalement plus uniformes que ceux du distributeur a orifices multiples. Dans la colonne montante avec un distributeur a tubes multiples, le gaz et les particules sont distribues plus uniformement dans la section, de sorte que l'acceleration de l'ecoulement est beaucoup plus uniforme et rapide. Le developpement de l'ecoulement est beaucoup plus rapide et la region pleinement developpee est atteinte pour la colonne montante avec le distributeur a tubes multiples. La conception du distributeur est un facteur important pour la conception du reacteur a lit fluidise circulant.

The present work focuses on developing a new comprehensive correlation for better prediction of the solids concentration in the fully developed region of co-current upward gas–solid flow in circulating fluidized bed (CFB) risers. Systematic experiments were carried out in two risers (15.1 m and 10.5 m high with the same 0.1 m i.d.) with FCC and sand particles. The results obtained from about 200 sets of operating conditions show that the average solids concentration in the fully developed region is more than just a function of the corresponding terminal solids concentration, as most previous correlations are based on. Operating conditions, particle properties and riser diameters also have significant effects on the solids concentrations in the fully developed region of CFB risers. Based on our experimental data and those reported in the open literature from CFB risers up to 0.4 m in diameter and 27 m in height with superficial gas velocities and solids circulation rates up to 11.5 m/s and 685 kg/m2·s, a new empirical correlation for predicting the average solids concentrations in the fully developed region of CFB risers is proposed. The correlation works well for a wide range of operating conditions, particle properties and riser diameters.

Hydrodynamic similarity in the fully developed zone of co-current upward gas–solid two-phase flow systems under different operating conditions was investigated by measuring the axial profiles of pressure gradient, radial profiles of solid concentration and particle velocity in two circulating fluidized bed (CFB) risers of 15.1 and 10.5 m high, with FCC and sand particles, respectively. The experimental data obtained from this work and in the literature show that when the scaling parameter, G s / ( ρ p U g ) , is modified as Fr D - 0.3 G s / ( ρ p U g ) , a detailed hydrodynamic similitude of the gas–solid flow in the fully developed zone of the risers under different operating conditions can be achieved. Furthermore, the experimental results from different gas–solid flow systems also show that as long as Fr D - 0.3 G s / ( ρ p U g ) remains constant, there is the same solid concentration in the fully developed zone of different CFB risers with different particles. With the same Fr D - 0.3 G s / ( ρ p U g ) , the local solid concentrations, the descending particle velocities, the cluster frequencies and the solid concentrations inside clusters in the fully developed zone of the risers all display the same axial and radial distribution, respectively. In other words, the empirical similarity parameter, Fr D - 0.3 G s / ( ρ p U g ) , appears to have incorporated the effects of operating parameters ( G s and U g ) , so that, the gas–solid flow in the fully developed zone of CFB risers under those different operating conditions but having the same Fr D - 0.3 G s / ( ρ p U g ) shows similar micro- and macro-hydrodynamic characteristics. The study shows that the empirical similarity parameter, Fr D - 0.3 G s / ( ρ p U g ) , is also independent of the upward gas–solid flow systems.

Friction between co-current upflow gas–solid flow and column wall was investigated by measuring apparent solids concentrations and actual ones in two circulating fluidized bed (CFB) risers with fluid catalytic cracking (FCC) and sand particles, respectively. A new model to predict frictional-pressure drops between the gas–solid flow in the fully developed zone and the column wall was developed. The results show that the friction between the gas–solid flow and the riser wall causes a significant deviation of the apparent solids concentration from the actual ones, especially under those operating conditions with higher superficial gas velocities and solids-circulation rates. When superficial gas velocities are greater than 8 m/s, the apparent solids concentrations in the fully developed zone of the risers can be greater than 60% of the actual ones. Particle diameters have different influences on the frictional-pressure loss under different superficial gas velocities. After the frictional-pressure drops predicted by the proposed model are deducted from the measured total pressure drops, the predicted actual solids concentrations agree well with the measured actual ones. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.

The combined influences of particle properties and nozzle gas distributor design on the axial and radial flow structure in two 100 mm i.d., 15.1 m and 10.5 m long risers with FCC and sand particles were investigated by measuring the axial pressure gradient profiles, and the axial and radial profiles of solids concentration. The results show that the nozzle gas distributor design has significant effects on the axial and radial flow structure for the FCC and sand particles. At lower superficial gas velocity of less than 8.0 m/s, the upward gas-solid flow of the sand particles decelerates in various degrees with the disappearing of the nozzle gas distributor effect. The upward gas-solid flow of the FCC particles, however, occurs without noticeable deceleration within the range of this study. In the acceleration section, the radial distributions of the local solids concentration of the FCC particles are more uniform than those of sand particles under the same operating conditions; while in the fully developed zone, the sand particles have a more uniform radial distribution than the FCC particles. The gas-solid flow is first developed in the center region, and then extends towards the wall. The overall flow development in the riser mainly depends on the local gas-solid flow in the wall region.

A power piezoelectric transformer (PT) was used to replace the conventional inductor-capacitor resonant tank to save valuable space and cost for ballast applications. In the past, the design of the PT or Transoner for the ballast circuit has been difficult due to the complex interaction between the physical and electrical equivalent circuit characteristics. Previous ballast design using the PT requires selecting available PT models that do not normally match the specific application, therefore resulting in poor efficiency. In this paper, a design procedure was established for a PT tailored to a 120-V 32-W power-factor-correction electronic ballast. A prototype Transoner based on this design was fabricated by Face Electronics Inc., Norfolk, VA, and was experimentally tested. The experimental results showed that the ballast using the designed PT can achieve unity power factor, zero-voltage switching, and 83% overall efficiency.

In a ballast circuit, the piezoelectric transformer (PT) is used to replace the conventional inductor-capacitor resonant tank saving valuable space and cost. During circuit operation, a very high voltage is required to initially ignite the lamp while during sustained operation the voltage requirements are significantly reduced. With ballast in mind, a design process has been developed to optimize a radial mode piezoelectric transformer or Transoner/sup /spl reg// to fit a specific application while simultaneously providing highly efficient performance and the capability to provide ZVS to the switches. The design procedure was verified by a custom-designed PT operating in a 32-watt ballast.

In this paper, multifractal analysis together with wavelet transform modulus maxima (WTMM) method is used to analyze the fluctuating signals of circulating fluidized bed (CFB). Singularity spectrum shows that the gas-particle flow in CFB has multifractal character. Motion behavior of the particle-fluid system of CFB can be described by singularity spectrum. Intermittency index can be used to determine the transition of flow regime from fast fluidization to pneumatic conveying.

A method was developed for quantitative determination of deuterium incorporated into live organisms or biological macromolecules. The deuterated biological material was mixed with a bovine serum albumin (BSA) supporter to make a homogeneous sample for which the deltaD value (vs. VSMOW) was analyzed using a dual-inlet gas isotope mass spectrometer. The method is described in detail, and the equation for calculation of deuterium content is presented, i.e., CbioD=1/500 x k x RVSMOW x CBSAH x 10(6) ppm. Deuterated hepatitis A virus (HAV) RNA and BSA were systematically investigated. The results demonstrate that the method is capable of direct measurement of deuterium content, and is highly repeatable and reliable with a standard deviation of +/-3 per thousand. It is stressed that the quantity of deuterated sample required is extremely small as a result of using BSA as supporter. The method may be applied in many fields, and has the strengths of simplicity, relative cheapness, and robustness.

Comparisons are made in a circulating fluidized-bed riser/downer system between a 15.1 m high, 0.10 m ID riser and a 9.3 m high, 0.10 m ID downer, based on the measurements of the radial distributions of the local solids holdups and local particle velocities along the two columns. Although the core-annulus flow structures exist in both the riser and downer, the radial flow structure in the downer differs largely from that in the riser. The radial distributions of solids holdup and particle velocity in the downer are much more uniform than those in the riser, thus ensuring the low back mixing and the narrow particle residence time distribution in the downer. The axial flow structure in the downer is also more uniform than that in the riser. Due to the high particle acceleration and the high particle velocity in the downer, the overall solids holdup is significantly lower than that in the riser. The microflow structure in the downer, characterized by the low intermittency indices, is also more uniform than that in the riser. These key properties of the downer make it a very promising candidate for industrial applications where short reaction times and high product selectivity are required.

The biodegradation of wastewater from the sugar industry is investigated in a three-phase biological fluidized bed reactor. In the inoculation experiment, the immobilized biofilm was found to keep dominant over the suspended biomass, and a stable biofilm of 175 microns thick was formed after 12 days. The continuous experiments for biodegradation of wastewater showed that, under the operation with hydraulic retention time of 3 h, the average COD and NH3-N removals reached to 85% and 80%, respectively, and the resultant effluent COD and NH3-N achieved the Chinese Discharge Standard of Water Pollutants for Sugar Industry (GB 21909-2008). The experiment for impact load showed that as the influent COD load changed stepwise from 2.3 to 5.1 kgCOD/m3·d, the reactor achieved the treatment effect without being affected in the performance. Finally, tracer experiments were performed to measure the internal circulation and residence time distribution (RTD) of wastewater in the reactor. It was found that the internal circulation of wastewater evidently exists in the reactor. Meanwhile, the RTD characteristics were described with the tanks-in-series model, and under the operating conditions, the calculated model parameter n was ranged from 1.19 to 1.27, which indicated that the flow pattern in the reactor is close to that in a CSTR. The internal circulation causes the organic matters in the influent to be effectively diluted within the reactor, and also promotes the organic matters to be fully degraded, so that the reactor can present high adaptability to the variation of organic load and high removal efficiency to COD and NH3-N. As a result, the biological fluidized bed reactor is suggested to be a prospective unit for the treatment of wastewater from sugar production process.

Objective: To explore the value of TCD and CDUS on diagnosis of large artery atherosclerosis. Methods: In our study, 90 patients who had been admitted to our hospital and diagnosed as LAA according to CISS typing were selected as the research object. A retrospective analysis was conducted, using CTA as golden standard for diagnoses of stenoses. Explore the risk factors of LAA, the reliability of TCD and CDUS in diagnosis of the stenosis and distribution of stenosis in each vessel. Results: Hypertension and type 2 diabetes are risk factors of LAA vascular stenosis. Middle cerebral artery stenosis detection by TCD carries the highest reliability (sensitivity 90.91%, specificity 97.89%, positive predictive value 96.15%, the negative predictive value was 94.9%, the positive likelihood ratio was 43.18, negative likelihood ratio 0.09, Kappa = 0.9). The consistency of TCD is as good as CTA in head and neck part. The negative coincidence rate was higher in the anterior circulation vessels (97.98%), followed by the coincidence rate of severe stenosis (95.23%). However, the detection rate of posterior circulation vessels positive, moderate and severe stenosis, mild stenosis gradually decreased by TCD. CDUS carries general reliability in detecting intracranial extracranial stenosis, the highest reliability in internal carotid artery (kappa 0.82), and the worst consistency in vertebral artery (kappa 0.38). The negative coincidence rate of CDUS in extracranial cerebrovascular stenosis was highest (97.22), followed by the overall compliance rate (91.55%). 242 branches of vascular stenosis were discovered in our study, among which intracranial artery stenosis 61.15% (148/242) is higher than that in extracranial artery 38.85% (90/242), ratio of moderate to severe stenosis is as high as 82.23% (199/242). Intracranial artery stenosis in ICA is extremely common (51.11%, 46/90), and MCA is the common area of intracranial artery stenosis (37.16%, 55/148). Conclusions: (1) Hypertension, type 2 diabetes are risk factors for LAA stenosis. (2) TCD detection of intracranial vascular stenosis carries the best consistency, and reliability of MCA is the highest. In our search, MCA possesses the highest rate of stenosis, and negative coincidence rate by TCD examination was the highest, which could be used for screening method for stenosis. The reliability of TCD in diagnosis of moderate and severe stenosis was relatively better than mild stenosis. (3) CDUS detection of anterior circulation lesions is better than that of posterior circulation lesions. Evaluate effect on moderate and severe stenosis was better than that of mild one. The ratio of ICA stenosis was the highest, but the effect on VA was poor. (4) The incidence of intracranial vascular stenosis is more common than that of the intracranial vascular stenosis.

In the ballast circuit, the piezoelectric transformer is used to replace the conventional inductor-capacitor resonant tank saving valuable space and cost. In the past, design of the piezoelectric transformer (PT) or Transonerreg for the ballast circuit has been difficult due to the complex interaction between the physical and electrical equivalent circuit characteristics. Previous ballast design using the PT requires selecting available PT models normally not matched to the specific application and therefore, resulting in poor efficiency. In this paper, a design procedure was established for a PT tailored to a 32 W 120 V PFC electronic ballast. A prototype Transoner based on this design was fabricated by Face Electronics and tested experimentally. The experimental results showed that the ballast using the designed PT can achieve unit power factor, zero voltage switching and a 83 % overall efficiency

The Inertially Stabilized Rifle is a new stabilized rifle system that can eliminate the disturbances induced by the shooter. Recurve actuator is used in this system to provide the precise movement of the rifle barrel. In such a portable device, only low voltage electrical sources are available yet the piezoelectric actuator needs high voltage to drive the actuator. The actuators consume little real power but a large amount of reactive power. Furthermore, the piezoelectric actuators are present an almost purely capacitive load. In this paper, we describe the development of a low input voltage amplifier for a high voltage piezoelectric actuator. This amplifier is based on switching technology so it efficiently handles the regenerative energy from the piezoelectric actuator. This amplifier consists of two stages. The first stage is a flyback converter which boosts the (low) input voltage to the maximum voltage required by the piezoelectric actuator. The second stage is a half-bridge amplifier which delivers the output voltage to the actuator as commanded by the reference signal. The basic structure of the amplifier is described, and its performance is characterized in terms of bandwidth, distortion, and efficiency.