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GEOS-Chem TOMAS (GCT) simulations of AERONET-inversion products during 2015 were compared with AERONET-inversion products from the multi-year climatology of AboEl-Fetouh et al. (2020) (AeF) and for year 2015 acquired over 5 stations in the North American and European Arctic. The GCT simulations of particle size distributions (PSD) did not capture a spring to summer radius increase of the fine mode (FM) peak observed by AeF but did capture AeF's springtime coarse mode (CM) peak (small-sized CM peak with a radius ∼ 1.3 μm) and a weak late summer/fall increase in the amplitude of that peak. The lack of a spring to summer FM radius increase was likely due to the large GCT cell size (4° × 5°) and associated difficulties in the modelling of coagulation-induced smoke particle size. Conversely, the GCT simulation of the small-sized CM peak indicated a successful capture of the springtime influx of Asian dust. The fall increase of that GCT peak was associated with an increase of a larger (4–7 μm) PSD mode that AeF suggested was due to local dust. GCT captured the seasonal (climatological-scale) FM AOD trend, the decreasing CM AOD trend, and the increasing trend of the FM fraction. The GCT CM AOD also showed a fall increase that was coherent with the increase of the simulated small-sized CM peak and with a lesser rate of decrease of the AeF CM AOD. Large GCT deviations from the AERONET retrievals were attributed to an extreme July 2015 forest fire event.

Water encroachment is a serious problem for developing an edge and bottom water reservoirs. The fracture–cavity gas reservoir has various reservoir media and strong heterogeneity, leading to the complex gas–water flow mechanism and trapped gas formation during water encroachment. Presently, no systematic study on the gas–water flow characteristics and trapped gas formation mechanism exists, especially through visual experiment. In this paper, the creation and testing of three types of visualization micromodels were described based on the CT scan images and microelectronic photolithography techniques. Subsequently, a 2D visual experiment was conducted initially to investigate the gas–water flow characteristics and the trapped gas formation mechanism intuitively. Then, ImageJ gray analysis method was utilized to study the distribution of trapped gas, saturation, and gas recovery quantitatively. Finally, several development suggestions were presented for different types of reservoirs based on the quantitative characterization results. Experimental results showed that the flow characteristics of fracture-, cavity-, and fracture–cavity-type micromodels are different during water encroachment, resulting from the large difference of microstructures. The trapped gas formed at dead ends or blind corners, circumfluence, and cutoff phenomenon, can be commonly found in three types of micromodels. However, the trapped gas formed at H-shaped channels, dumbbell-shaped channels, and microfractures are specific to certain micromodels. The main factors that influence the trapped gas formation are capillary force, hydrodynamic force, Jamin effect (the additional resistance effect of the bubble when it traverses narrow pores), and pore–throat connectivity. Quantitative results reflect that approximately 76% of the trapped gas in the cavity-type micromodel is formed by circumfluence and cutoff phenomenon, whereas approximately 67% of the trapped gas in the other two micromodels is formed at network of microfractures, dead ends, and blind corners. In addition, the ultimate gas recovery of cavity-type reservoirs increases while the displacement differential pressure increases; by contrast, the ultimate gas recovery of fracture- and fracture–cavity-type micromodels increases initially and then decreases with the increase in displacement differential pressure. The visual investigation presented not only improves our intuitive understanding of the gas–water flow mechanism in fracture–cavity carbonate reservoirs but also provides a novel image analysis method for quantitative characterization of visual experiments.

The impact of biomass burning (BB) on aerosol optical properties and radiative budget in the polar region following an intense boreal fire event in North America in July 2015 is explored in this paper. Presented data are obtained from the Navy Aerosol Analysis and Prediction System (NAAPS) reanalysis and the Fu-Liou radiative transfer model. NAAPS provides particle concentrations and aerosol optical depth (AOD) at 1° x 1° spatial and 6-hourly temporal resolution, its AOD and vertical profiles were validated with field measurements for this event. Direct aerosol radiative forcings (ARF) at the surface, the top of the atmosphere (TOA) and within the atmosphere are calculated for clear-sky and all-sky conditions, with the surface albedo and cloud properties constrained by satellite retrievals. The mean ARFs at the surface, the TOA, and within the atmosphere averaged for the north pole region (latitudes north of 75.5N) and the study period (July 5–15, 2015) are −13.1 ± 2.7, 0.3 ± 2.1, and 13.4 ± 2.7 W/m2 for clear-sky and −7.3 ± 1.8, 5.0 ± 2.6, and 12.3 ± 1.6 W/m2 for all-sky conditions respectively. Local ARFs can be a several times larger e.g. the clear-sky surface and TOA ARF reach over Alaska −85 and −30 W/m2 and over Svalbard −41 and −20 W/m2 respectively. The ARF is found negative at the surface (almost zero over high albedo region though) with the maximum forcing over the BB source region, and weaker forcing under all-sky conditions compared to the clear-sky conditions. Unlike the ARFs at the surface and within the atmosphere, which have consistent forcing signs all over the polar region, the ARF at the TOA changes signs from negative (cooling) over the source region (Alaska) to positive (heating) over bright surfaces (e.g., Greenland) because of strong surface albedo effect. NAAPS simulations also show that the transported BB particle over the Arctic are in the low-to-middle troposphere and above low-level clouds, resulting in little difference in ARFs at the TOA between clear- and all-sky conditions over the regions with high surface albedo. Over dark surfaces, the negative TOA forcing increases with AOD about 50% slower under all-sky conditions compared to clear-sky case. The boreal BB event resulted in large magnitude of ARFs and the high variabilities of the forcings over the polar region has a significant impact on the polar weather conditions and important implications for the polar climate.

How to further optimize the thermoelectric figure of merit of silicon (Si) nanostructure? Constructing the layered structure composed of two different Si nano morphologies should be viewed an effective approach. The figure of merit of the layered structure could be further optimized by tuning the different contribution from the composed nano morphologies on the electron and phonon transport. In order to reveal the thermoelectric transport mechanism, the electronic structure, the lattice dynamics and the thermoelectric properties of Si nanosphere, Si nanoribbon and the layered structure composed of the two nano morphologies were investigated through first-principles calculation, lattice dynamics simulation and Boltzmann transport theory. The results suggest that the figure of merit of the layered structure is improved significantly in whole although its specific thermoelectric parameters are unsatisfactory as compared to the single nano morphologies. Therefore we provide a complete understanding on the thermoelectric transport of the layered structure and an effective route to further optimize the figure of merit of Si nanostructure.

A vacuum membrane distillation (VMD) model was developed and the VMD experiment of sodium chloride (NaCl) was carried out. Three different commercial hydrophobic PTFE flat-sheet membranes were used in our VMD experiments. Membrane characteristics, such as morphology, thickness, porosity, pore size distribution, hydrophobic and liquid entry pressure of water (LEPw) were investigated. The VMD experiments were carried out under different conditions of various feed temperatures, feed flow rates, feed concentrations and permeate side vacuum degrees. To validate the model, it was tested with an experimental case study of literature [Naidu et al., 2014]. The VMD model has been validated with the data obtained from our laboratory experiments and has been proved that the model can be used to predict the permeation flux on the overall process performance.

Background The efficacy and safety of prostate SBRT in men with mCRPC is unknown. Materials and methods A prospective cohort study was conducted with 125 men diagnosed with mCRPC. All patients received ADT plus chemotherapy. Patients were randomly assigned to receive daily prostate SBRT (36–48 Gy in 6–8 fractions). Patients who did not receive SBRT served as controls. Results The primary endpoints were PFS and OS. After 89 months of total follow-up, the median PFS was 13.8 months in the SBRT group (n = 61) and 12.0 months in the control group (n = 64) (HR, 0.87; 95% CI, 0.61–1.24; P = 0.249). The OS was 25.7 months in the SBRT group and 23.8 months in the control group (HR, 0.93; 95% CI, 0.65–1.33; P = 0.230). A non-significant increase in the PSA response rate (50.8% vs. 43.7%) and time to PSA progression (8.3 months vs. 7.0 months) was observed in the SBRT group compared to the control group; however, the time to symptomatic progression was significantly prolonged in the SBRT group (11.3 months) compared to the control group (8.5 months) (HR, 0.76; 95% CI, 0.53–1.08; P = 0.019). There was an 11.5% incidence of radiation cystitis and radiation rectitis in the SBRT group, and the degree and incidence of hormone-related and chemotherapy-related adverse events were similar between the two groups. Conclusion Adding prostate SBRT significantly prolonged the time to symptomatic progression and non-significantly prolonged PFS and OS among men with mCRPC compared to treatment with ADT plus chemotherapy alone.

This paper presents the climatology of aerosol optical properties and radiative forcing over the Arctic obtained within the framework of the iAREA (impact of absorbing aerosols on radiative forcing in the European Arctic) project. The presented data were obtained from the Navy Aerosol Analysis and Prediction System (NAAPS) and the Fu-Liou radiative transfer model. NAAPS was used to simulate particle concentration and aerosol optical depth (AOD) at 1 ° × 1 ° spatial resolution. Direct aerosol radiative forcing (ARF) was calculated for clear-sky and all-sky conditions based on NAAPS reanalysis (with AOD assimilation) and satellite observations of surface and cloud properties. Long-term data (2003–2015) from NAAPS show that anthropogenic and biogenic aerosol, as well as sea salt, make the most important contribution to total AOD (35 and 30%, respectively). However, smoke (15%) and mineral dust (20%) cannot be neglected, especially during spring and summer. Results of numerical simulations indicate mean shortwave (SW) ARF for the whole Arctic (>70.5oN) at the Earth's surface to be −4 W/m2 for clear-sky and −1.3 W/m2 for all-sky conditions, and at top of the atmosphere (TOA) −1.3 W/m2 and -0.4 W/m2, respectively. TOA ARF for anthropogenic and biogenic particles is only −0.1 W/m2 for clear-sky and almost zero for all-sky conditions. For smoke and dust particles, SW ARF is very similar for both Earth's surface and TOA, as well as for clear-sky and all-sky conditions. For sea salt, SW ARF is the same at the surface and at TOA: 0.6 W/m2 for clear-sky and −0.3 W/m2 for all-sky conditions, because of negligible solar absorption. Cloud cover reduces surface cooling (direct clear-sky SW ARF) by a factor of 40% and shifts TOA SW ARF towards positive values.

The impact of moderately absorbing aerosols on the energy budget over Central Europe is discussed, based on experimental observations and numerical simulations obtained for the summer of 2015. Aerosol events, defined as aerosol optical depth (AOD) at 500 nm greater than 0.15, especially in August, are mostly attributed to transport of biomass burning (BB) from Eastern Europe. Shortwave (SW) aerosol radiative forcings (ARF) at the surface and the top of the atmosphere (TOA) are estimated from ensembles of ten and eight observational and model-based approaches, respectively. Different measuring methods, including unmanned aviation system (UAS) and ground-based measurements, radiative transfer models, including MOTRAN and Fu-Liou, and parameterisations of aerosol optical properties regarding full vertical profiles, columnar and surface properties, are used in these approaches. The mean ARF is −15.9 ± 2.1 W/m2, -9.1 ± 1.4 W/m2, and 7.0 ± 1.0 W/m2, respectively, for the Earth's surface, TOA, and atmosphere under clear conditions for June–August 2015. During an aerosol event with AOD peak of about 0.6 at 500 nm, the daily mean surface, TOA, and atmosphere ARF are around −30, −18, and 13 W/m2, respectively. The mean ARF differences between all methods are about 4.0 W/m2 for the surface and about 2.3 W/m2 for the TOA, which correspond to 23% of ensemble means. Aerosols are also shown to have a significant impact on observed surface sensible and latent heat fluxes for the study period. Flux sensitivity to AOD for a solar zenith angle of 45° is −70 ± 41 W/m2/τ500, -112 ± 56 W/m2/τ500, and -119 ± 19 W/m2/τ500, respectively, for sensible, latent, and net SW and longwave (LW) radiation flux. When averaged over day time, sensitivities of sensible heat, latent heat fluxes, and net radiation fluxes to AOD are reduced by about 50%, 20%, and 70%, respectively.