Vapor Products Research Articles

GNSS/MET Station Equipment Maintenance and Product Application

Based on the use of Global Navigation Satellite System (GNSS) for meteorological detection in the world, we used the GNSS/MET detection equipment in the meteorological departments of Liaoning Province of China and its data to study and summarize the maintenance methods of GNSS/MET (Global Navigation Satellite System Meteorology) detection equipment and the application of water vapor products in operational systems. The results show that: 1) For GNSS/MET failures, specific inspections and classifications can be performed according to different phenomena; 2) The GNSS water vapor measurement station samples every 30 seconds, forming one set of GNSS data every hour, and can detonate the atmospheric precipitation by solving the original data; 3) Using the “Navigation Satellite Remote Sensing Water Vapor Application Management System”, the GNSS/MET water vapor products can be directly displayed. We can get the conclusion that GNSS/MET has far-reaching significance for studying the law of atmospheric water vapor changes and enhancing the ability to monitor severe weather such as heavy rain and strong convection.

Surface Temperatures and Water Ice Sublimation Rate of Oxo Crater: A Comparison With Juling Crater

AbstractDwarf planet Ceres is characterized by several sites hosting (or have hosted) ice‐rich patches as revealed by the Dawn's Visible and InfraRed spectrometer. The study of the illumination conditions including the effects of the local topography become critical in the estimation of the ice lifetime as well as the water vapor production rate. In this work we applied a 3‐D thermophysical model in order to study the illumination conditions on the shape model, derived on the basis of the images acquired by the Dawn's Framing Camera during the Survey mission phase, and to calculate the surface temperatures and water sublimation rates. We are interested in a crater in the northern hemisphere (42°), Oxo, which hosts water ice in its southern wall. A comparison with the surface temperatures and water sublimation rates of another Ceres' crater, Juling, is carried out. Water ice sublimation rate of its ice‐rich patch suggests that the Oxo crater probably is not the source of the emission detected by Herschel, a source that could be represented instead by the Juling crater.

Enhanced debromination by Fe particles during the catalytic pyrolysis of non-metallic fractions of printed circuit boards over ZSM-5 and Ni/SiO2-Al2O3 catalyst

A two-stage fixed-bed reactor was used to investigate the catalytic pyrolysis of non-metallic fractions of printed circuit boards (PCBs) over ZSM-5 and Ni/SiO2-Al2O3 (Ni/SA) catalysts. The addition of Fe particles to the catalyst was evaluated for bromine removal from the pyrolysis products. Results showed that the oil yield was significantly reduced from 50.1 wt% to 41.2 wt% by ZSM-5 catalyst and 36.0 wt% by Ni/SA catalyst, respectively, with corresponding increases of aqueous and gas products. The addition of Fe particles to ZSM-5 catalyst slightly altered the product yields, whereas the mixture of Fe and Ni/SA catalyst largely reduced the oil yield to 25.6 wt%, along with the highest gas yield of 20.3 wt%. The results suggested that the mixture of Fe-Ni/SA catalyst accelerated the cracking of vapor products derived from PCBs rather than the Fe-ZSM-5 mixture. Moreover, ZSM-5 catalyst favored the formation of single ring aromatics in the oils, such as benzene and toluene. The presence of Fe particles increased the concentration of phenol in the oils. The ZSM-5 and Ni/SA catalyst demonstrated great debromination performance for the conversion of organobromine compounds into HBr, reducing the bromine content in oils from 8.74 wt% to 5.96 wt% and 5.46 wt%, respectively. Furthermore, the addition of Fe particles reduced both the organobromine compounds and evolved HBr, which resulted in less than 3.8% of Br being transferred in the oil whereas more than 50% of bromine was fixed in Fe particles.

Cloud mask-related differential linear adjustment model for MODIS infrared water vapor product

Water vapor is the primary greenhouse gas of the Earth-atmosphere system and plays a vital role in understanding climate change, if correctly measured from satellites. The Moderate Resolution Imaging Spectroradiometer (MODIS) can monitor water vapor retrievals at near-infrared (nIR) bands in the daytime as well as at infrared (IR) bands in both daytime and night time. However, the accuracy of IR retrievals under confident clear conditions (>99% probability) is much poorer than that of nIR retrievals. Additionally, IR retrievals under unconfident clear conditions (>95%, >66% and ≤66% probabilities) are usually discarded because the possible presence of clouds would further reduce their accuracy. In this study, we develop a cloud mask-related differential linear adjustment model (CDLAM) to adjust IR retrievals under all confident clear conditions. The CDLAM-adjusted IR retrievals are evaluated with the linear least square (LS) adjusted nIR retrievals under confident clear condition and Global Positioning System (GPS) observations under different probabilities of clear conditions. Both case studies in the USA and global (65° S~65° N) evaluation reveal that the CDLAM can significantly reduce uncertainties in IR retrievals at all clear-sky confidence levels. Moreover, the accuracy of the CDLAM-adjusted IR retrievals under unconfident clear conditions is much better than IR retrievals without adjustment under confident clear conditions, highlighting the effectiveness of the CDLAM in enhancing the accuracy of IR retrievals at all clear-sky confidence levels as well as the data availability improvement of IR retrievals after adjustment with the CDLAM (14% during the analyzed time periods). The most likely reason for the efficiency of the CDLAM may be that the deviation of the differential water vapor information derived by the differential process is significantly shrunken after the linear regression analysis in the presented model. Therefore, the CDLAM is a promising tool for effectively adjusting IR retrievals under all probabilities of clear conditions and can improve our knowledge of the water vapor distribution and variation.

Characterization of solid and vapor products from thermochemical conversion of municipal solid waste woody fractions

The ever-increasing consumption of material goods with economic growth is resulting in an increasing generation of municipal solid waste (MSW) and the rapid filling of landfills. Fractions of municipal solid waste containing wood-based products have the potential to be used for the development of value added products. In this paper we produced and characterized biochar and pyrolysis vapors from municipal solid waste (MSW) woody fractions to demonstrate their suitability towards soil amendments. Carbonization work focused on compost overs, molded wood pallets, treated wood, sawmill cut ends, wood derived fuels, furniture, painted wood, plywood, oriented strand board and particle boards from Washington State recycling facilities. The goal of this research is to use these biochars as soil amendments; however, there are concerns with both the potential presence of condensed organic pollutants and trace metals. The presence of trace metals and polycyclic aromatic hydrocarbons (PAH) in all the biochars produced were examined. GC-MS analyses of liquid extracts did not reveal the presence of soluble PAH compounds. High concentrations of mercury (Hg) and arsenic (As) were found in the biochar made from painted wood and treated wood, respectively. Among the methods tested for the removal of trace metals, acid washing was found to be the most effective. The volatiles released from the analyzed MSW fractions were also analyzed in Py-GC-MS studies. Among these volatile compounds, many contained Cl, N, or S, which could be potential sources of pollution if the pyrolysis vapors are combusted.

Microbubble aeration enhances performance of vacuum membrane distillation desalination by alleviating membrane scaling

Membrane fouling, especially inorganic fouling due to salt crystal formation and deposition on the membrane surface, is still a major technical issue in membrane distillation (MD) applications. In this study, microbubble aeration (MBA) was included in a laboratory-scale vacuum membrane distillation (VMD) rig and its effect on a desalination process was examined. Without MBA, serious membrane scaling occurred during desalination of simulated high-salinity sea water (100 g.L−1 salt concentration), which resulted in a dramatic reduction of permeate flux to essentially zero after 120 min. Scanning electron microscopy showed that a layer of large cuboid salt crystals uniformly covered the membrane surface. However, membrane scaling was mitigated with the introduction of MBA, resulting in the improved VMD desalination performance, which was positively correlated with pump pressure in the microbubble (MB) generator. Results showed that the effective processing time of the VMD desalination processing cycle was respectively prolonged to 150, 180, and more than 300 and 360 min (cf. 120 min without MBA) when the pump pressure was respectively at 0.1, 0.2, 0.3 and 0.4 MPa, leading to the increase of cumulative water production. Further studies found that larger numbers of MBs of smaller size were produced at higher pump pressure, which are more beneficial for increasing water vapor production and alleviating salt precipitation. The difference in zeta potential between the MBs in distilled water (about −30 mV) and that in SW100 solution (about -2 mV) demonstrated that MBA not only effectively mitigated the negative effect of concentration polarization by enhancing the surface shear rate at the membrane surface, but also reduced salt precipitation probably due to the MBs attracting counterions to the gas-water interface. Finally, energy consumption analysis of the modified VMD desalination process revealed that MBA, while itself only adding about 3% to the total energy consumption at varied pump pressures, was able to improve the specific energy consumption, especially at higher pump pressures. Together, these results demonstrate that MBA is an effective way of improving the performance of VMD desalination of water.

U.S. Adult Attitudes About Electronic Vapor Product Use in Indoor Public Places

The U.S. Surgeon General has concluded that aerosol from electronic vapor products, such as e-cigarettes, can contain harmful and potentially harmful constituents. This study assessed the prevalence and determinants of U.S. adult attitudes toward electronic vapor product use in indoor public places. Data from 2017 Summer Styles, an Internet survey of U.S. adults aged ≥18 years (n = 4,107) were analyzed in 2017. Respondents were asked, Do you favor or oppose allowing the use of electronic vapor products in indoor public places such as workplaces, restaurants, and bars? Responses were strongly favor, somewhat favor, somewhat oppose, and strongly oppose. Multivariate Poisson regression was used to determine sociodemographic correlates of opposition (somewhat or strongly). In 2017, a total of 82.4% of adults strongly or somewhat opposed the use of electronic vapor products in indoor public places, including 28.0% of current (past 30-day) electronic vapor product users and 52.7% of current cigarette smokers. After adjustment, opposition was significantly lower among current and former electronic vapor product users than never users, current cigarette smokers than never smokers, and people living with tobacco product users. Opposition was significantly higher among adults aged ≥45 years than those aged 18-24 years and among adults who had rules prohibiting electronic vapor product use in their vehicles or homes than those without such rules. Approximately eight in ten U.S. adults, including more than one quarter of electronic vapor product users, opposed electronic vapor product use in indoor public places. Prohibiting electronic vapor product use in indoor public areas can protect bystanders from the health risks of secondhand electronic vapor product aerosol exposure.

Assessments of GMI-Derived Precipitable Water Vapor Products over the South and East China Seas Using Radiosonde and GNSS

Satellite remote sensing of the atmospheric water vapor distribution over the oceans is essential for both weather and climate studies. Satellite onboard microwave radiometer is capable of measuring the water vapor over the oceans under all weather conditions. This study assessed the accuracies of precipitable water vapor (PWV) products over the south and east China seas derived from the Global Precipitation Measurement Microwave Imager (GMI), using radiosonde and GNSS (Global Navigation Satellite System) located at islands and coasts as truth. PWV measurements from 14 radiosonde and 5 GNSS stations over the period of 2014–2017 were included in the assessments. Results show that the GMI 3-day composites have an accuracy of better than 5 mm. A further evaluation shows that RMS (root mean square) errors of the GMI 3-day composites vary greatly in the range of 3∼14 mm at different radiosonde/GNSS sites. GMI 3-day composites show very good agreements with radiosonde and GNSS measured PWVs with correlation coefficients of 0.896 and 0.970, respectively. The application of GMI products demonstrates that it is possible to reveal the weather front, moisture advection, transportation, and convergence during the Meiyu rainfall. This work indicates that the GMI PWV products can contribute to various studies such as climate change, hydrologic cycle, and weather forecasting.

On the water transport behavior and phase transition mechanisms in cold start operation of PEM fuel cell

An analytical dynamic model is proposed to predict the cold start behavior of proton exchange membrane (PEM) fuel cell. Water phase transition mechanisms have been reconstructed based on the five states of water migrating in the fuel cell, composed of water vapor, super-cooled water (liquid water), ice, membrane water (water dissolved in solid electrolyte) and frozen membrane water, in order to explore the reasonable water production and phase transition mechanism. The general water transfer behavior during cold start operation of PEM fuel cell finally evolves into four stages: (1) unsaturated water in ionomer and membrane water production; (2) water in ionomer reaching saturation; (3) over-saturated water in ionomer and quick desorption into liquid and vapor in pores; and (4) significant ice formation. Both non-equilibrium and equilibrium methods to simulate phase transition have been carried out to reveal water transport characteristics in the cold start operation. The assumptions associated with the liquid water and vapor production in the electrochemical reaction extensively involved in the previous modeling studies in the literature should be cautiously used, especially for the dynamic modeling studies. It is worthwhile addressing that the liquid water inside the cathode CL follows the slow increasing and rapid decreasing trend during the cold start operation, which indicates that the liquid water should mostly freeze at the shut-down moment. Furthermore, water prefers to freeze on the interface between catalyst layer (CL) and micro-porous layer (MPL), leading to the liquid water accumulation here migrating towards the membrane side.

Development of a Regression Model for Estimating Daily Radiative Forcing Due to Atmospheric Aerosols from Moderate Resolution Imaging Spectrometers (MODIS) Data in the Indo Gangetic Plain (IGP)

The assessment of direct radiative forcing due to atmospheric aerosols (ADRF) in the Indo Gangetic Plain (IGP), which is a food basket of south Asia, is important for measuring the effect of atmospheric aerosols on the terrestrial ecosystem and for assessing the effect of aerosols on crop production in the region. Existing comprehensive analytical models to estimate ADRF require a large number of input parameters and high processing time. In this context, here, we develop a simple model to estimate daily ADRF at any location on the surface of the IGP through multiple regressions of AErosol RObotic NETwork (AERONET) aerosol optical depth (AOD) and atmospheric water vapour using data from 2002 to 2015 at 10 stations in the IGP. The goodness of fit of the model is indicated by an adjusted R2 value of 0.834. The Jackknife method of deleting one group (station data) was employed to cross validate and study the stability of the regression model. It was found to be robust with an adjusted R2 fluctuating between 0.813 and 0.842. In order to use the year-round ADRF model for locations beyond the AERONET stations in the IGP, AOD, and atmospheric water vapour products from MODIS Aqua and Terra were compared against AERONET station data and they were found to be similar. Using MODIS Aqua and Terra products as input, the year-round ADRF regression was evaluated at the IGP AERONET stations and found to perform well with Pearson correlation coefficients of 0.66 and 0.65, respectively. Using ADRF regression model with MODIS inputs allows for the estimation of ADRF across the IGP for assessing the aerosol impact on ecosystem and crop production.

History and Current Trends in the Electronic Cigarette Retail Marketplace in the United States: 2010-2016.

The US market for electronic nicotine delivery systems (ENDS) has grown rapidly in the last decade. There is limited published evidence examining changes in the ENDS marketplace prior to the US Food and Drug Administration's (FDA) deeming rule in 2016. This study describes US ENDS retail market trends from 2010 to 2016. National data were obtained from Nielsen retail scanners for five product types: (1) disposables, (2) rechargeables, (3) cartridge replacements, (4) e-liquid bottle refills, and (5) specialty vapor products. We examined dollar sales, volume, price, brand, and flavor. Adjusted national sales increased from $11.6 million in 2010 to $751.2 million in 2016. The annual rate of sales growth rapidly increased before slowing through 2015. The rate of growth spiked in 2016. Market share for menthol products and other assorted flavors increased from 20% in 2010 to 52.1% by 2016. NJOY's early market dominance shifted as tobacco industry brands entered the market and eventually captured 87.8% of share by 2016. Rechargeables and accompanying products comprised an increased proportion of total volume sold over time while disposable volume declined. Specialty vapor products appeared at retail in 2015. Findings show strong early growth in the ENDS retail market followed by considerable slowing over time, despite a slight uptick in 2016. Trends reflect shifts to flavored products, newer generation "open-system" devices, lower prices, and tobacco industry brands. This study provides a baseline against which to compare the impact of FDA's 2016 deeming rule and future actions on the ENDS marketplace. This study uses market scanner data from US retail outlets to describe trends in the ENDS retail market from 2010 to 2016, providing a baseline against which to compare the impact of FDA's 2016 deeming rule and future actions on the ENDS marketplace. Understanding historical market trends is valuable in assessing how future regulatory efforts and advances in ENDS technology may impact industry response and consumer uptake and use.

Quantitative analysis of vaporous ammonia by online derivatization with gas chromatography ‐ mass spectrometry with applications to ammonium nitrate-based explosives

A novel method for the detection of vaporous products was developed utilizing a derivatizing agent collected onto a cryo-cooled gas chromatograph (GC) inlet, with analysis by gas chromatography-mass spectrometry (GC-MS). The technique was applied to the detection of ammonia, which has been difficult to detect at trace levels, particularly in the presence of other chemical interferents, due to its small mass and high volatility. To address this, the ammonia is derivatized in the inlet with butyl chloroformate to produce butyl carbamate, a compound that is retained by GC columns and compatible with standard GC-MS analysis. This method was then used to quantify the ammonia headspace vapor concentration produced from the dissociation of bulk ammonium nitrate as well as from mixtures with aluminum and petroleum jelly, which are fuels commonly used in homemade explosives (HMEs).

Oxidative stress responses in human bronchial epithelial cells exposed to cigarette smoke and vapor from tobacco- and nicotine-containing products

The use of novel tobacco- and nicotine-containing vapor products that do not combust tobacco leaves is on the rise worldwide. The emissions of these products typically contain lower numbers and levels of potentially harmful chemicals compared with conventional cigarette smoke. These vapor products may therefore elicit fewer adverse biological effects. We compared the effects of emissions from different types of such products, i.e., our proprietary novel tobacco vapor product (NTV), a commercially available heat-not-burn tobacco product (HnB), and e-cigarette (E-CIG), and a combustible cigarette in a human bronchial epithelial cell line. The aqueous extract (AqE) of the test product was prepared by bubbling the produced aerosol into medium. Cells were exposed to the AqEs of test products, and then glutathione oxidation, Nrf2 activation, and secretion of IL-8 and GM-CSF were examined. We found that all endpoints were similarly perturbed by exposure to each AqE, but the effective dose ranges were different between cigarette smoke and the tobacco- and nicotine-containing vapors. These results demonstrate that the employed assays detect differences between product exposures, and thus may be useful to understand the relative potential biological effects of tobacco- and nicotine-containing products.

Pool Boiling of Low-GWP Replacements for R134a on a Reentrant Cavity Surface.

This paper quantifies the pool boiling performance of R134a, R1234yf, R513A, and R450A on a flattened, horizontal reentrant cavity surface. The study showed that the boiling performance of R134a on the Turbo-ESP exceeded that of the replacement refrigerants for heat fluxes greater than 20 kWm-2. On average, the heat flux for R1234yf and R513A was 16 % and 19 % less than that for R134a, respectively, for R134a heat fluxes between 20 kWm-2 and 110 kWm-2. The heat flux for R450A was on average 57 % less than that of R134a for heat fluxes between 30 kWm-2 and 110 kWm-2. A model was developed to predict both single-component and multi-component pool boiling of the test refrigerants on the Turbo-ESP surface. The model accounts for viscosity effects on bubble population and uses the Fritz (1935) equation to account for increased vapor production with increasing superheat. Both loss of available superheat and mass transfer resistance effects were modeled for the refrigerant mixtures. For most heat fluxes, the model predicted the measured superheat to within ± 0.31 K.

Adolescent Weight and Electronic Vapor Product Use: Comparing BMI-Based With Perceived Weight Status

This study examined the associations of BMI-based and perceived body weight status with electronic vapor product use, cigarette smoking, and dual use among U.S. adolescents. A cross-sectional analysis was conducted in 2017 on data from 15,129 adolescents in the National Youth Risk Behavior Survey, 2015. Multiple logistic regression analyses were used to examine the associations of BMI-based and perceived weight status with electronic vapor product use, cigarette smoking, and dual use, after adjusting for all other covariates. The regression models were stratified by gender. Overall, 25.5% of males used electronic vapor products, 11.6% smoked cigarettes, and 8.1% used both; percentages among females were 22.6%, 9.8%, and 6.8%, respectively. Females who perceived themselves as overweight were more likely than those who perceived themselves as normal weight to be current electronic vapor product users (AOR=1.09, 95% CI=1.01, 1.19) and dual users (AOR=1.23, 95% CI=1.01, 1.49). When compared with normal BMI-based category, males with obese BMI status were more likely to be current cigarette smokers (AOR=1.61, 95% CI=1.06, 2.44), however, only females with overweight BMI status were more likely to be current smokers (AOR=1.89, 95% CI=1.25, 2.86). Findings suggest that the influence of adolescents' body weight perceptions and BMI-based status should be accounted for when developing nicotine-containing product use prevention programs for adolescents. Specific strategies for influencing female adolescents who perceive themselves as overweight should be included to prevent emerging electronic vapor product and dual use.

Understanding Users' Vaping Experiences from Social Media: Initial Study Using Sentiment Opinion Summarization Techniques.

BackgroundE-liquid is one of the main components in electronic nicotine delivery systems (ENDS). ENDS review comments could serve as an early warning on use patterns and even function to serve as an indicator of problems or adverse events pertaining to the use of specific e-liquids—much like types of responses tracked by the Food and Drug Administration (FDA) regarding medications.ObjectiveThis study aimed to understand users’ “vaping” experience using sentiment opinion summarization techniques, which can help characterize how consumers think about specific e-liquids and their characteristics (eg, flavor, throat hit, and vapor production).MethodsWe collected e-liquid reviews on JuiceDB from June 27, 2013 to December 31, 2017 using its public application programming interface. The dataset contains 27,070 reviews for 8058 e-liquid products. Each review is accompanied by an overall rating and a set of 4 aspect ratings of an e-liquid, each on a scale of 1-5: flavor accuracy, throat hit, value, and cloud production. An iterative dichotomiser 3 (ID3)-based influential aspect analysis model was adopted to learn the key elements that impact e-liquid use. Then, fine-grained sentiment analysis was employed to mine opinions on various aspects of vaping experience related to e-liquids.ResultsWe found that flavor accuracy and value were the two most important aspects that affected users’ sentiments toward e-liquids. Of reviews in JuiceDB, 67.83% (18,362/27,070) were positive, while 12.67% (3430/27,070) were negative. This indicates that users generally hold positive attitudes toward e-liquids. Among the 9 flavors, fruity and sweet were the two most popular. Great and sweet tastes, reasonable value, and strong throat hit made users satisfied with fruity and sweet flavors, whereas “strange” tastes made users dislike those flavors. Meanwhile, users complained about some e-liquids’ steep or expensive prices, bad quality, and harsh throat hit. There were 2342 fruity e-liquids and 2049 sweet e-liquids. There were 55.81% (1307/2342) and 59.83% (1226/2049) positive sentiments and 13.62% (319/2342) and 12.88% (264/2049) negative sentiments toward fruity e-liquids and sweet e-liquids, respectively. Great flavors and good vapors contributed to positive reviews of fruity and sweet products. However, bad tastes such as “sour” or “bitter” resulted in negative reviews. These findings can help businesses and policy makers to further improve product quality and formulate effective policy.ConclusionsThis study provides an effective mechanism for analyzing users’ ENDS vaping experience based on sentiment opinion summarization techniques. Sentiment opinions on aspect and products can be found using our method, which is of great importance to monitor e-liquid products and improve work efficiency.

Optimization of thermal desorption conditions for recovering wood preservative from used railroad ties through response surface methodology

A statistical response surface methodology (RSM) using a central composite design (CCD) model was applied to identify the optimum thermal desorption conditions for maximum recovery of preservative from copper naphthenate (CuNap) treated wood and subsequent production of a high quality pyrolytic vapor from the thermally treated wood. From the designed experiment, 94% of the total preservative present in the ties was desorbed at temperatures higher than 250 °C and residence times longer than 30 min. Elevating the temperature from 215 °C to 285 °C for 45 min residence time generated a weight loss of 12–36 wt%, an increase in higher heating value (HHV) from 20.1 to 21.9 MJ/kg, and a reduction of energy yield from 90.4 to 71.5% of the resulting thermally treated biomass. Pyrolysis at 450 °C of this material produced a vapor rich in sugars- and lignin-derived compounds. The predicted optimum conditions in terms of a maximum preservative recovery, minimum energy yield loss of the wood, and production of thermally treated biomass that generates a high proportion of sugars- and lignin-derived compounds during pyrolysis were found to be 265 °C and 51 min. Under these optimum conditions, the predicted maximum preservative recovery was 95% while the predicted thermally treated solid retained 77% of the original energy yield and produced high portions of levoglucosan and lignin-derived compounds during subsequent pyrolysis, similar to torrefied wood.

New Structure of Large-Sized Protonic Ceramic Fuel Cell with Porous Alloy

Introduction Some perovskite oxides, such as doped BaCeO3 and BaZrO3 electrolyte-based protonic ceramic fuel cell (PCFC) have received increasing attention as electrolytes of reduced temperature to operate [1,2]. Furthermore, PCFC leads to the production of water vapor at the cathode side, which helps to improve the conversion efficiency of SOFC system. And it is possible to reduce the cost of the stack because inexpensive metal materials can be used for interconnectors in stacks. However most of the previous researches on PCFC are small-sized cell and it is necessary to further improve the power density. In this work, we reported that a cell stack of a new structure was designed and made with large-sized PCFC and porous alloys for anode and cathode current collector to improve power density, and the characteristics were evaluated. Experimental 2.1 Preparation of large-sized PCFCBaCe0.8Y0.2O3-δ(BCY20) and BaZr0.8Y0.2O3-δ(BZY20) were prepared by solid state reaction method and were mixed with NiO by a ball-mill to prepare an anode powder. The powder was pressed uniaxially under 40 MPa into anode pellet. On anode pellet BCY20 and BZY20 electrolyte layer were deposited by a screen printing and co-sintered at 1450 ºC for 10 hours. LSCF cathode powder was also deposited and sintered at 1000 ºC. Figure 1(A) shows an optical image of a large-sized PCFC. 2.2 Preparation of Ni and Ni-Sn porous metalsA polyurethane foam with interconnected cells was treated to become electrically conductive. This was followed by the application of a predetermined amount of nickel via electrodeposition. The base material, or plastic foam, was removed through heat treatment at 800 ºC. The remaining nickel was reduced in a reducing gas at approximately 1000 ºC to become a nickel porous metal. Next, the Ni porous metal was coated with a predetermined amount of Sn by electrodeposition. Additionally, this was heat-treated in a reducing gas at approximately 1000 ºC to become a Ni-Sn porous alloy by means of Sn diffusion into Ni. Figure 1(B) shows an SEM image of the surface of the Ni-Sn porous alloy [3]. Result The power generating characteristics of a single-PCFC in which Ni-Sn porous alloy and Ni porous metal were applied as a cathode and anode collector was evaluated at the operating temperature of 600 ºC. Peak power densities of 500 mW/cm2 and 333 mW/cm2 were achieved, respectively, at 600 ºC and 500 ºC operating on hydrogen fuel. [1] H. Iwahara, et al., Solid State Ionics, 61, 65 (1993) [2] J. Dailly, et al., Journal of Power Sources, 240, 323 (2013) [3] C. Hiraiwa, et al., International Journal of Hydrogen Energy, 42, 12567 (2017) Figure 1

An improved atmospheric correction method in repeat-pass InSAR measurements

ABSTRACTAs is well known, the problem of atmospheric phase delays is currently one of the major limitations to high precision repeat-pass interferometric synthetic aperture radar (InSAR) applications. Therefore, accurately mitigating atmospheric phase delays is a key but unresolved problem. In recent decades, many researchers have attempted to mitigate the atmospheric phase delays. A typical method is to calculate the atmospheric phase along radar line of sight direction using precipitable water vapour products. However, this method completely neglects the atmospheric turbulence and heterogeneity in the horizontal direction when the zenith wet delays are converted to slant wet delays, reducing the accuracy of the approach. In this article, we systematically analysed the atmospheric turbulence and heterogeneity in the horizontal direction as well as the vertical stratification of water vapour in the troposphere. From this analysis, we found that the atmospheric turbulence and heterogeneity in the horizontal direction cannot be neglected in estimating atmospheric phase delays. Moreover, the vertical stratification of water vapour and the satellite orbit azimuth can be integrated into the calculation of slant phase delays. We therefore propose an improved atmospheric correction method in repeat-pass InSAR measurements, weighted-sampling radiometer correction. The proposed method was applied to the investigation of ground subsidence in an area of Beijing, China to validate its feasibility and accuracy. The results illustrate that atmospheric phase delays and ground subsidence information can be retrieved more accurately using the proposed method than was obtained using the conventional method.

Investigating the yield of H<sub>2</sub>O and H<sub>2</sub> from methane oxidation in the stratosphere

Abstract. An important driver of climate change is stratospheric water vapor (SWV), which in turn is influenced by the oxidation of atmospheric methane (CH4). In order to parameterize the production of water vapor (H2O) from CH4 oxidation, it is often assumed that the oxidation of one CH4 molecule yields exactly two molecules of H2O. However, this assumption is based on an early study, which also gives evidence that this is not true at all altitudes. In the current study, we re-evaluate this assumption with a comprehensive systematic analysis using a state-of-the-art chemistry–climate model (CCM), namely the ECHAM/MESSy Atmospheric Chemistry (EMAC) model, and present three approaches to investigate the yield of H2O and hydrogen gas (H2) from CH4 oxidation. We thereby make use of the Module Efficiently Calculating the Chemistry of the Atmosphere (MECCA) in a box model and global model configuration. Furthermore, we use the kinetic chemistry tagging technique (MECCA-TAG) to investigate the chemical pathways between CH4, H2O and H2, by being able to distinguish hydrogen atoms produced by CH4 from H2 from other sources.We apply three approaches, which all agree that assuming a yield of 2 overestimates the production of H2O in the lower stratosphere (calculated as 1.5–1.7). Additionally, transport and subsequent photochemical processing of longer-lived intermediates (mostly H2) raise the local yield values in the upper stratosphere and lower mesosphere above 2 (maximum > 2.2). In the middle and upper mesosphere, the influence of loss and recycling of H2O increases, making it a crucial factor in the parameterization of the yield of H2O from CH4 oxidation. An additional sensitivity study with the Chemistry As A Boxmodel Application (CAABA) shows a dependence of the yield on the hydroxyl radical (OH) abundance. No significant temperature dependence is found. We focus representatively on the tropical zone between 23° S and 23° N. It is found in the global approach that presented results are mostly valid for midlatitudes as well. During the polar night, the method is not applicable.Our conclusions question the use of a constant yield of H2O from CH4 oxidation in climate modeling and encourage to apply comprehensive parameterizations that follow the vertical profiles of the H2O yield derived here and take the chemical H2O loss into account.