Vapor Products Research Articles

Optimizing Images for an E-Cigarette Messaging Campaign: Liking and Perceived Effectiveness.

Introduction: Given the prevalence of electronic vapor product (EVP) use among young people in the US, there is a need for effective vaping education campaigns. This study tested 32 images for liking and perceived effectiveness (PE) to identify optimal images for a messaging campaign. Method: Images were selected from current campaigns, warning labels, and other images based on young adult reasons for use. Images were coded for the presence of (1) people, (2) vapor, (3) device, (4) color, and (5) similarity to warning label image. Young adults (n = 200) were recruited from the Amazon Mechanical Turk platform. Participants were randomly assigned to view and rate six of the 32 images on liking as well as PE, which measured the potential impact of the image to discourage vaping appeal and use. Results: Images containing vapor and/or a device or e-liquid were not well-liked but were perceived as effective in discouraging vaping (ps < 0.05). Images from warning labels were also not well-liked but were perceived as significantly more effective than those not from a warning (p < 0.01). Liking and effectiveness of features was similar for both EVP users and non-users. Discussion: Images with specific features were rated as less likable but rated as higher on PE. However, the consistency of image features rated as effective by EVP users and non-users supports the utility of similar imagery for vaping prevention and reduction efforts.

Multiscale simulation of rapid solidification of an aluminium–silicon alloy under additive manufacturing conditions

At present, most multiscale simulation approaches to model the temperature evolution of the molten pool, and the resulting microstructure evolution for selective laser melting, assume an equilibrium freezing range and steady state solidification conditions. This is despite the solidification conditions being observed to be highly unsteady and non-equilibrium. These two assumptions lead to inaccurate predictions of the temperature evolution of the molten pool and thus microstructure predictions. To demonstrate this, an approach to scale-bridging computational models of the laser additive manufacturing process is presented, in which the temperature history is passed from a macroscale molten pool simulation to a microscale phase-field simulation. This linkage is achieved by volume mapping of the temperature field from the grid of the molten pool simulation to the grid of the microstructure simulation. To describe the system evolution at the scale of the molten pool, a computational fluid dynamics (CFD) method that captures the laser–metal interaction, vapour production, gas recoil pressure, fluid flow, surface tension, Marangoni flow, and heat conduction, convection, and radiation is applied. To capture the chemical kinetics of the phase-transition, a non-equilibrium CALPHAD-integrated phase-field (PF) model is applied. The discrepancy between the predictions of the solid front isotherm is quantified as ⩾ 100 K for an Al-10Si alloy under the large observed cooling rate. This leads to a spatial discrepancy in the solidification front between the CFD model, which assumes equilibrium freezing behaviour, and the PF model, which does not, of approximately 10 µm over 50 µs in the present case. Under these conditions, present formulations of multiphase CFD cannot accurately predict the solidification behaviour because of the assumption of equilibrium at the solid–liquid interface. Strategies for reconciling this discrepancy for materials that exhibit rapid solidification under large thermal undercooling will need to be developed for multiscale simulation of additive manufacturing to advance.

Lasers developed in the Institute of Atmospheric Optics of the SB RAS (a review)

The results of research on the development of the first electric discharge lasers on active media N2, CO2, Cu, CuBr and excimer molecules at the Institute of Atmospheric Optics named after V. E. Zueva SB RAS are given. It created one of the world's first Cu-lasers with a pulse production of copper vapors due to the explosion of conductors and a transverse excitation discharge. For a copper laser, record specific generation parameters were obtained almost equal to the limit: radiation energy 2.4 J/l, peak power 120 MW/l with an efficiency of 0.16 %. For the CuBr laser operating in frequency mode, for the first time, an average radiation power of more than 100 W was obtained. In the dual pulse excitation mode, conditions were found that limit the growth of the efficiency of the CuBr laser. For him, a record efficiency of 2.7 % was obtained. For the first time, a nitrogen laser was developed with a maximum efficiency of 0.27 % with an&#x0D; energy of 0.8 mJ, a peak power of 160 kW. For the first time, a miniature XeCl laser with a longitudinal excitation discharge was developed, which worked both with and without buffer gases He, Ne and Ar.

Perancangan Sistem Fire Alarm Kebakaran Pada Gedung Laboratorium XXX

Abstract&#x0D; &#x0D; Fire is a phenomenon that occurs when a material reaches a critical temperature and reacts chemically with oxygen (for example) producing heat, flame, light, smoke, water vapor, carbon monoxide, carbon dioxide, or other products and effects. Fires can occur anywhere, be it in office buildings, residences or public facilities. As for other than in public areas, fires often occur, both in rooms and laboratories, the triggers are almost the same due to negligence and not being careful in using flammable tools. For this reason, the need for a fire detector with a detector system using an alarm so that once a fire occurs, all those in the building can find out through the detector with an alarm sound as a fire marker. In order to reduce casualties, the need for a sprinkler system to extinguish the fire, and can assist the officers or authorities in the building as soon as possible. From the above problems, this research will determine how many detectors and sprinklers are needed, as well as how much water volume, pump power, and ground water tank are needed. This type of research is quantitative research by direct observation of the object under study, then researchers measure the room one by one using a building meter. From the calculation results by taking a sample on the 1st floor, the number of detectors needed is 10 smoke detectors and 3 heat detectors, the number of sprinklers is 47, the volume of water needed is 846 m3, the pump power and ground water tank needed are hydraulic power. pump (HHP) 3,28621 kW, pump shaft power (BHP) 4.38 kW, pump electric power (P) 6 kW, diesel pump (PpD) 4 HP, jocky pump (PJk) 0.6 kW, capacity GWT ( QGWT) 44 m3.

Impacts of tropical cyclones on the thermodynamic conditions in the tropical tropopause layer observed by A-Train satellites

Abstract. The tropical tropopause layer (TTL) is the transition layer between the troposphere and the stratosphere. Tropical cyclones may impact the TTL by perturbing the vertical distributions of cloud, temperature, and water vapor. This study combines several A-Train instruments, including radar from CloudSat, lidar from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, and the Atmospheric Infrared Sounder (AIRS) on the Aqua satellite, to detect signatures of cyclone impacts on the distribution patterns of cloud, water vapor, temperature, and radiation by compositing these thermodynamic fields relative to the cyclone center location. Based on the CloudSat 2B-CLDCLASS-LIDAR product, this study finds that tropical cyclone events considerably increase the occurrence frequencies of TTL clouds, in the form of cirrus clouds above a clear troposphere. The amount of TTL cloud ice, however, is found to be mostly contributed by overshooting deep convection that penetrates the base of the TTL at 16 km. To overcome the lack of temperature and water vapor products in cloudy conditions, this study implements a synergistic method that retrieves temperature, water vapor, ice water content, and effective radius simultaneously by incorporating observations from AIRS, CloudSat, and CALIPSO. Using the synergistic method, we find a vertically oscillating pattern of temperature anomalies above tropical cyclones, with warming beneath the cloud top (around 16 km) and cooling above. Based on water vapor profiles retrieved by the synergistic method, we find that the layer integrated water vapor (LIWV) above 16 km is higher above tropical cyclones, especially above overshooting deep convective clouds, compared to climatological values. Moreover, we find that the longwave and net radiative cooling effect of clouds prevails within 1000 km of tropical cyclone centers. The radiative heating effects of clouds from the CloudSat 2B-FLXHR-LIDAR product are well differentiated by the collocated brightness temperature of an infrared window channel from the collocated AIRS L1B product. By performing instantaneous radiative heating rate calculations, we further find that TTL hydration is usually associated with radiative cooling of the TTL, which inhibits the diabatic ascent of moist air across isentropic surfaces to the stratosphere. Therefore, the radiative balance of the TTL under the impact of the cyclone does not favor the maintenance of moist anomalies in the TTL or transporting water vertically to the stratosphere.

Drop impact on superheated surfaces: short-time dynamics and transition to contact

When a volatile drop impacts on a superheated solid, air drainage and vapour generation conspire to create an intermediate gas layer that delays or even prevents contact between the liquid and the solid. In this article, we use high-speed synchronized reflection interference and total internal reflection imaging to measure the short-time dynamics of the intermediate gas film and to probe the transition between levitation and contact. We observe that the substrate temperature strongly affects the vertical position of the liquid–gas interface and that the dynamic Leidenfrost transition is influenced by both air and vapour drainage (i.e. gas drainage), and evaporation, the latter giving rise to hitherto unreported vertical oscillations of the gas film that can trigger liquid–solid contact. We first derive scaling relations for the height of the gas film trapped under the drop's centreline, called the dimple height, and the minimum film thickness at short times. The former is set by a competition between gas drainage and liquid inertia, similarly as for isothermal impacts, while the latter strongly depends on the vapour production. The gas pressure, at the location where the minimum thickness is reached, is determined by liquid inertia and vapour production and ultimately balanced by the increasing interfacial curvature, determining the minimum thickness. We show that, in the low impact velocity limit, the transient stability of the draining gas film remarkably makes dynamic levitation less demanding than static levitation. We characterize the vertical gas film oscillations by measuring their frequency and monitoring their occurrence in the parameter space spanned by surface temperature and impact velocity. Finally, we model the occurrence of these oscillations and account for their frequency through a hydrodynamic mechanism.

Evaluation of MODIS Water Vapour Products over ALGERIA using Radiosonde Data

Remote sensing of atmospheric water vapour using GNSS and Satellite data has become an efficient tool in meteorology and climate research. Many satellite data have been increasingly used to measure the content of water vapour in the atmosphere and to characterize its temporal and spatial variations. In this paper, we have used observations from radiosonde data collected from three stations (Algiers, Bechar and Tamanrasset) in Algeria from January to December 2012 to evaluate Moderate Resolution Imaging Spectroradiometer (MODIS) total precipitable water vapour (PWV) products. Results show strong agreement between the total precipitable water contents estimated based on radiosondes observations and the ones measured by the sensor MODIS with the correlation coefficients in the range 0.69 to 0.95 and a mean bias, which does not exceed 1.5.

The Perfect Storm? COVID-19 and Substance Use amongst Social Work Students in the USA

During the COVID-19 pandemic, health risk behaviours related to substance use have been recognised as a significant public health concern amongst university students. Understanding the mechanisms of substance use behaviours, including those used to cope with COVID-19-related stressors, is imperative to curate targeted prevention efforts. To that end, we examined substance use prevalence and its associations with socio-demographic characteristics, preventive behaviours, and mental health amongst US social work students. We collected data from 457 students across all degree levels (BSW, MSW and PhD) from July to August 2020 through an online survey, to examine thirty-day patterns of substance use behaviours related to cigarettes, electronic vapour products, alcohol, binge drinking and marijuana. Univariate and bivariate analyses revealed high rates of substance use behaviours, particularly alcohol use (71 per cent), binge drinking (35 per cent) and marijuana use (25 per cent). Findings also revealed significant associations amongst substance use, socio-demographic characteristics, and mental health. Amongst other implications, our study should encourage social work programmes to promote positive coping strategies amongst students and foster substance abuse prevention efforts, both to mitigate health risk behaviours and to enhance student well-being, both during and after the COVID-19 pandemic.

Numerical simulation of water production from humid air for Khuzestan province: Investigation of the Peltier effect (thermoelectric cooling system) on water production rate

The effect of applying a thermoelectric cooling system (TEC) in an air-water generator system is studied in present study. This study is focused on changing thermoelectric cold surface temperature on the water productivity amount from the air that is knwon as condensation. For this purpose, 12 numerical samples evaluated in which the temperature of the thermoelectric cold surface varies from 1 °C to 12°C. The temperature and relative humidity of the ambient air in all samples are fixed and equal to 35 °C and 80 %, respectively. To observe the distribution of properties, velocity field, temperature field, the velocity contour, isotherms, and mass fraction gradient are displayed, and the mass fraction gradient distribution diagram is shown on the cold thermoelectric surface. Also, the values of the water condensation rate in each sample are mentioned and compared. Finally, by examining the samples, it is found that the decrease in temperature was directly related to the increase in production and condensation of water vapor in the air. Therefore the highest production rate obtained in minimum temperature of the cold surface with the amount of 0.323kg.m−2.hr−1. Based on results, 11oC temperature reduction in the cold side of thermoelectric cooling system cause 36.8% increase in water production rate.

BTEX and Nitrogen Oxides fume Assessments in Fuel Dispense Stations and Residential Areas

Fuel vapors are released from storage tanks through vent pipes and from filling pump fuel dispensary stations. These petroleum-based by-products are introduced into ambient atmospheres and neighboring areas and may become a potential health risk. To investigate the quantity of benzene, toluene, ethylbenzene, and xylene (BTEX) and nitrogen oxides (NOx) concentrations as they are considered air pollutants and proven that they have negative health impacts on human. A selected fuel dispensing stations within Kuwaiti residential areas, passive samplers were deployed within selected fuel stations and also several residential areas for one week. Findings reveal that the concentration of BTEX at the fuel dispensing stations was significantly elevated than it was for the breathing pipe in residential areas. The concentration of benzene of 5.5 μg/m3 is slightly higher than the mean ambient concentrations in the rural and urban areas that 1 μg/m3 and 5–20 μg/m3, respectively. The levels are higher near such sources of benzene emission as fuel dispensing stations. As a result, the benzene close to the fuel stations is higher up to 70 μg/m3. Emissions escalate during weather change because of meteorological variables like temperature and wind direction influence dispersion of noxious compounds in the ambient air. With significant additions of harmful petroleum products into Kuwaiti air, a weary for respiratory and digestive implications may be paving the way to cause an ecological uproar. Hence, the government should use this baseline data and provide guidance to fuel dispensary stations for an improved method of fuel dispense, improvising fuel storing to minimise temperature change for fuel state preservation and, use of nozzles that increase dispensary speeds while minimising vapour production.

Determination of Formaldehyde Yields in E-Cigarette Aerosols: An Evaluation of the Efficiency of the DNPH Derivatization Method

Recent reports have suggested that (1) formaldehyde levels (measured as a hydrazone derivative using the DNPH derivatization method) in Electronic Nicotine Delivery Systems (ENDS) products were underreported because formaldehyde may react with propylene glycol (PG) and glycerin (Gly) in the aerosol to form hemiacetals; (2) the equilibrium would shift from the hemiacetals to the acetals in the acidic DNPH trapping solution. In both cases, neither the hemiacetal nor the acetal would react with DNPH to form the target formaldehyde hydrazone, due to the lack of the carbonyl functional group, thus underreporting formaldehyde. These reports were studied in our laboratory. Our results showed that the aerosol generated from formaldehyde-fortified e-liquids provided a near-quantitative recovery of formaldehyde in the aerosol, suggesting that if any hemiacetal was formed in the aerosol, it would readily hydrolyze to free formaldehyde and, consequently, form formaldehyde hydrazone in the acidic DNPH trapping solution. We demonstrated that custom-synthesized Gly and PG hemiacetal adducts added to the DNPH trapping solution would readily hydrolyze to form the formaldehyde hydrazone. We demonstrated that acetals of PG and Gly present in e-liquid are almost completely transferred to the aerosol during aerosolization. The study results demonstrate that the DNPH derivatization method allows for an accurate measurement of formaldehyde in vapor products.

Assimilation of OLCI total column water vapour in the Met Office global numerical weather prediction system

AbstractThe representation of water vapour in numerical weather prediction models is still subject to significant uncertainties, which are partly due to the lack of observations of water vapour in the lower troposphere over land and sea‐ice areas. There are now several satellite datasets of total column water vapour available, which make use of the reflected radiances from the surface in the near‐infrared spectral region where there are water vapour absorption bands. The ocean and land cover imager (OLCI) on the Sentinel‐3A and 3B satellites measures the top of atmosphere radiances in the near infrared, and a total column water vapour product is retrieved and made available in near real time. Comparisons of the total column water vapour from OLCI with NWP model 6‐h forecasts, collocated ground‐based GNSS measurements and radiosonde profiles have been undertaken to determine the accuracy of the product. Following the monitoring, some experiments were made to assimilate the OLCI total column water vapour over land using the Met Office 4D‐Var assimilation system. A 5‐month trial assimilating the OLCI data has shown consistently positive impacts on the forecast scores with some changes to the water vapour distribution in the model.

A comparative study of the effect of phase change material (paraffin wax) on volumetric and surface direct solar steam generation

BackgroundThe rate of evaporation in direct solar steam generation can be increased by employing several techniques. One of the passive techniques that can be used for the improvement of system performance is the use of phase change materials (PCMs). MethodsAn experimental study was carried out to explore the role of PCMs in energy storage and continuous evaporation in a direct solar steam generation (SSG) system. For this purpose, volumetric and surface methods have been employed and compared in the absence and presence of PCMs. A nanofluid composed of MWCNT@GNP (a nanocomposite of graphene and multiwall carbon nanotubes) and water was used as a photoabsorber in the volumetric method, whereas poplar wood coated with MWCNT@GNP was chosen for the surface method. Significant resultsThe results indicated that paraffin wax PCMs around the bulk fluid with benefiting from excellent capability of energy storage gave a superb performance for continuance of vapor production in both methods. The PCMs have a significant impact on maintaining the evaporation rate at night. However, in the presence of PCMs, the photoabsorber in the volumetric method represented much better performance compared to the surface method.

The Type of Substance Use Mediates the Difference in the Odds of Sexual Risk Behaviors Among Adolescents of the United States.

BackgroundAlthough the relationship between sexual risk behaviors and substance use has been established, It remains to be studied if different types of substances have differences in the odds of sexual risk behaviors. Therefore, we aimed to identify the prevalence of sexual risk behaviors in high school students of the United States (US) and study the difference in the odds of sexual risk behaviors for various substances.MethodsWe performed a retrospective cross-sectional study using Youth Risk Behavior Surveillance System (YRBSS) data of 2019 that nationally represents US high school students in grades 9-12. We identified individuals with sexual risk behaviors as participants with four or more lifetime sexual partners and who did not use a condom during the last intercourse.ResultsOut of 11,191 participants, 463 (3.9%) engaged in sexual risk behaviors. The prevalence of substance use, including anabolic steroids (11.5 vs. 1.1%), cocaine (27.2 vs. 2.0%), marijuana (87.1 vs. 34.7%), alcohol (92.4 vs. 54.3%), e-cigarette (90.3 vs. 48.0%), and traditional cigarette (62.2 vs. 21.6%) was higher in participants with sexual risk behaviors compared to participants with no sexual risk behaviors (p<0.0001 for all substances). In regression analysis, anabolic steroid use was associated with the highest odds of sexual risk behaviors (adjusted odds ratio (aOR):4.87, 95%CI: 2.48-9.57; p<0.0001) followed by cocaine (aOR:3.80, 1.80-8.00; p=0.001), marijuana (aOR:3.36, 1.64-6.89; p<0.0001), alcohol (aOR:2.41, 1.05-5.55; p=0.039), electronic vapor products (2.05, 1.004-4.19; p=0.049), and traditional cigarette use (aOR:1.58, 1.10-2.28; p=0.016). We did not find a statistically significant increase in the odds of sexual risk behaviors for the rest of the substances.ConclusionAlthough the prevalence of sexual risk behaviors is low, the prevalence of substance use is significantly higher in participants with sexual risk behaviors. Among the different types of substances, anabolic steroid use has the highest odds of sexual risk behaviors. Therefore, clinicians should remain vigilant for anabolic steroid use when screening adolescents for substance use. Further large-scale randomized studies are needed to study the effects of anabolic steroids on sexual risk behaviors.

Gender-moderated associations between adolescent mental health, conventional substance use, and vaping

Existing studies have overlooked the moderating effect of gender on the associations between mental health, conventional substance use, and electronic vapor product (EVP) use, colloquially called “vaping.” Thus, this study examined whether mental health problems and conventional substance use have different effects on EVP use among female and male adolescents. Data were drawn from the CDC’s 2019 Youth Risk Behavior System Survey. A multivariate hierarchical logistic regression was conducted using a national sample of high school students in the United States (N = 13,677). The results showed statistically significant associations between mental health problems and EVP use, as well as between conventional substance use and EVP use, among adolescents. Furthermore, gender was a significant moderator that influences both associations. Specifically, the impact of mental health problems on EVP use was greater among female adolescents than among their male counterparts. Conversely, the impacts of current cigarette and marijuana use on EVP use were greater among male adolescents than among their female counterparts. Effective prevention and intervention programs should consider and address these co-occurrences of mental health problems, substance use, and EVP use differently for male and female adolescents.

Hygrothermal Analysis of CLT-Based Retrofit Strategy of Existing Wall Assemblies According to EN 13788 Standard

In the framework of the ongoing EU-funded innovation project called e-SAFE (energy and Seismic Affordable rEnovation solutions), several solutions for the energy and seismic deep renovation of reinforced-concrete (RC) framed buildings in the EU countries are going to be developed and demonstrated. One of these solutions makes use of cross laminated timber (CLT) panels connected to the existing RC frame through specifically designed dampers to increase the seismic and energy performances of the existing envelope. This paper aims to preliminary assess the hygrothermal performance of such CLT panels when applied to various typical wall structures under different climate conditions in Italy through numerical simulations carried out according to the EN 13788 Standard and considering various indoor vapor production classes. Results show that the most problematic existing wall structures are uninsulated concrete walls, for which a risk of surface condensation and mold growth is predicted in all climate zones because of their low thermal resistance (U-value of 3.55 W·m-2·K-1), followed by uninsulated solid brick walls (U-value of 1.81 W·m-2·K-1). The application of CLT panels is found to not only significantly improve the thermal behaviour of the walls, but also to eliminate any surface and interstitial condensation issues in all climate zones.

Evaluation and Calibration of MODIS Near-Infrared Precipitable Water Vapor over China Using GNSS Observations and ERA-5 Reanalysis Dataset

Water vapor is one of the most important parameters in climatic studies. MODerate-resolution Imaging Spectroradiometer (MODIS) is a key instrument and can provide spatially continuous precipitable water vapor (PWV) products. This study was focused on the performance evaluation of the MODIS near-infrared PWV product (MOD-NIR-PWV) over China. For a comprehensive assessment of the performance of MOD-NIR-PWV, PWV retrieved from the measurements at the global navigation satellite systems (GNSS) stations (i.e., GNSS-PWV) and the ERA5 reanalysis dataset (ERA-PWV) from 2013 to 2018 were used as the reference. To investigate the suitability of using ERA-PWV as the reference for the evaluation, ERA-PWV was compared to the high-accuracy GNSS-PWV at 246 GNSS stations and PWV retrieved from radiosonde observations (RS-PWV) at 78 radiosonde stations over China. The results showed that the mean bias and mean root-mean-square (RMS) of the differences between ERA-PWV and GNSS-PWV across all the stations were 0.5 and 1.7 mm, respectively, and the mean correlation coefficient of the two datasets was above 0.96. The values were 0.4 and 1.9 mm and 0.97, respectively, for the differences between ERA-PWV and RS-PWV. This suggests the suitability of ERA-PWV as the reference for the evaluation of MOD-NIR-PWV. In addition, MOD-NIR-PWV was compared with both GNSS-PWV and ERA-PWV, and their mean bias and mean RMS were 2.9 and 3.8 mm (compared to GNSS-PWV) and 2.1 and 3.0 mm (compared to ERA-PWV), respectively. The positive bias values and the non-normal distribution of the differences between MOD-NIR-PWV and both reference datasets imply that a considerable systematic overestimation of MOD-NIR-PWV over China may exist. To mitigate the systematic bias, ERA-PWV was utilized as the sample data due to its spatial continuities, and a grid-based calibration model was developed based on the annual and semiannual periodicities in the differences between MOD-NIR-PWV and ERA-PWV at each grid point. After applying the calibration model to correct MOD-NIR-PWV, the calibrated MOD-NIR-PWV was compared with ERA-PWV and GNSS-PWV for precision and accuracy analysis, respectively. The comparison showed that the model could significantly improve the precision by 94% and accuracy by 53%, which manifested the effectiveness of the calibration model in improving the performance of MOD-NIR-PWV over China.

A systematic assessment of water vapor products in the Arctic: from instantaneous measurements to monthly means

Abstract. Water vapor is an important component in the water and energy cycle of the Arctic. Especially in light of Arctic amplification, changes in water vapor are of high interest but are difficult to observe due to the data sparsity of the region. The ACLOUD/PASCAL campaigns performed in May/June 2017 in the Arctic North Atlantic sector offers the opportunity to investigate the quality of various satellite and reanalysis products. Compared to reference measurements at R/V Polarstern frozen into the ice (around 82∘ N, 10∘ E) and at Ny-Ålesund, the integrated water vapor (IWV) from Infrared Atmospheric Sounding Interferometer (IASI) L2PPFv6 shows the best performance among all satellite products. Using all radiosonde stations within the region indicates some differences that might relate to different radiosonde types used. Atmospheric river events can cause rapid IWV changes by more than a factor of 2 in the Arctic. Despite the relatively dense sampling by polar-orbiting satellites, daily means can deviate by up to 50 % due to strong spatio-temporal IWV variability. For monthly mean values, this weather-induced variability cancels out, but systematic differences dominate, which particularly appear over different surface types, e.g., ocean and sea ice. In the data-sparse central Arctic north of 84∘ N, strong differences of 30 % in IWV monthly means between satellite products occur in the month of June, which likely result from the difficulties in considering the complex and changing surface characteristics of the melting ice within the retrieval algorithms. There is hope that the detailed surface characterization performed as part of the recently finished Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) will foster the improvement of future retrieval algorithms.

Upcycling polyamide containing post-consumer Tetra Pak carton packaging to valuable chemicals and recyclable polymer

Billion tons of post-consumer Tetra Pak cartons are discarded annually as land and ocean wastes, creating significant environmental problems and resource losses. Recycling of the carton wastes is hindered by its multi-material compositions and low values of the recycled products. In this study, a novel upcycling of the cartons was investigated. A post-consumer carton consisting of paper, polyolefin, and polyamide was directly converted in 210–230 °C tetrahydrofuran containing 10–20 mM acid to produce up to 19.2% of levoglucosenone and 8.6% of furfural by selectively decomposing paper fraction. The remaining solids containing mostly intact polyethylene and polyamide but also a smaller fraction of paper-derived char were separated using a solvent-dissolution method. The xylene-soluble fraction was a recycled polymer similar to the original polyethylene, which was verified by its functional groups, the composition of the pyrolysis products, and the melt rheology results. The xylene-insoluble fraction was a mixture of polyamide and paper-derived char. Upon pyrolysis, caprolactam was produced as the only major vapor product. The remaining, thermally stable paper-derived char could be used as a high-quality solid fuel. Overall, the demonstrated recycling method could potentially maximize the values of the products recovered from carton wastes.

A NOVEL PROCEDURE FOR GENERATION OF SAR-DERIVED ZTD MAPS FOR WEATHER PREDICTION: APPLICATION TO SOUTH AFRICA USE CASE

Abstract. The knowledge of tropospheric water vapor distribution can significantly improve the accuracy of Numerical Weather Prediction (NWP) models. The present work proposes an automatic and fast procedure for generating reliable water vapor products from the synergic use of Sentinel-1 Synthetic Aperture Radar (SAR) imagery and Global Navigation Satellite System (GNSS) observations. Moreover, a compression method able to drastically reduce, without significant accuracy loss, the water vapor dataset dimension has been implemented to facilitate the sharing through cloud services. The activities have been carried in the EU H2020 TWIGA project framework, aimed at providing water vapor maps at Technology Readiness Level 7.