Application of Milankovitch cycles in the restoration of highresolution deposition velocity of Neogene strata in Kutei Basin,Indonesia

Restoring the deposition velocity during evolution in basin analysis is an important aspect.The restoration of high-resolution deposition velocitydthe deposition velocity over a short geological perioddcan improve the precision of basin analysis and research.However,the prerequisite for the restoration is to establish an accurate chronostratigraphic framework based on precise stratigraphic dating.Conventional methods for stratigraphic dating can only be used to determine the epochs of large stratigraphic intervals rather than accurate geological time.It is also difficult to establish a fine geological time scale with dating methods requiring sample testing such as isotopic dating due to their limitations in sample collection.In contrast,the Milankovich cycle-based dating possesses the advantages of high precision and high operability and can be used to restore high-resolution deposition velocity.Based on the identification and extraction of Milankovich cycles,this study restores the high-resolution deposition velocity of the Middle Miocene and later strata in the abyssal area of the Kutei Basin in Indonesia.The results show that the restored deposition velocity coincides well with lithological sections.This indicates that the Milankovitch cycle-based dating can be used to effectively restore reliable curves of high-resolution deposition velocity.Therefore,this study provides a methodological basis and data guarantee for studying the accumulation cycles and distribution patterns of oil and gas in the abyssal area of the Kutei Basin using wave analysis technology and can also serve as a reference for similar research in other basins.

Atmospheric Sulfur Deposition for a Red Soil Broadleaf Forest in Southern China

A two-year study in a typical red soil region of Southern China was conductedto determine 1) the dry deposition velocity (V_d) for SO_2 and particulate SO_4^(2-) above abroadleaf forest, and 2) atmospheric sulfur fluxes so as to estimate the contribution of variousfractions in the total. Using a resistance model based on continuous hourly meteorological data,atmospheric dry sulfur deposition in a forest was estimated according to V_d and concentrations ofboth atmospheric SO_2 and particulate SO_4^(2-). Meanwhile, wet S deposition was estimated based onrainfall and sulfate concentrations in the rainwater. Results showed that about 99% of the drysulfur deposition flux in the forest resulted from SO_2 dry deposition. In addition, the observeddry S deposition was greater in 2002 than in 2000 because of a higher average concentration of SO_2in 2002 than in 2000 and not because of the average dry deposition velocity which was lower for SO_2in 2002. Also, dry SO_2 deposition was the dominant fraction of deposited atmospheric sulfur inforests, contributing over 69% of the total annual sulfur deposition. Thus, dry SO_2 depositionshould be considered when estimating sulfur balance in forest ecological systems.

Screening of the Indoor Plants for Removing Formaldehyde

[ Objective] The research aimed to screen out the best ornamental houseplants to remove formaldehyde from indoor air through deposition velocity and to explore the pathways of plants for formaldehyde removal. [ Method] Fifty-three indoor ornamental plant species were experimen- ted in series of sealed chambers （volumes of O. 096 m^3 ） by formaldehyde fumigation with the internal concentration of （1 ± 0. 1 ） mg/L in this study. The removal efficiency of formaldehyde was assessed by the uptake fluxes and the deposition velocity of formaldehyde. [ Result] Six species of indoor plants （ Hedera helix, Ficus elastica Roxb. ex Hornem, Nephrolepis exaltata cv. Bostoniensis, Begonia evansiana, Mentha canadensis L. and Adiantum capillus-veneris Linn. ） with high formaldehyde removal efficiency were firstly screened out. Significance analysis of the deposition velocity by Statistical Program for Social Sciences （SPSS） presented that tested plants belonging to the same genera or family had similar ability to remove formaldehyde pollution. The diurnal variations of deposition velocity for the six plants were then tested further. The results showed that four of them, including Ficus elastica Roxb. ex Hornem, Nephrolepis exaltata cv. Bostoniensis, Mentha canadensis L. and Adiantum capi//us-veneris Linn. re- moved formaldehyde mainly by leaves surface adsorption, while Begonia evansiana and Hedera helix by stomatal uptake, f Conclusion Begonia evansiana and Hedera helixare the most efficient indoor plants among the 53 species studied for phytoremediation of the air formaldehyde pollution.

Particle deposition in ventilation duct with convex or concave wall cavity

A numerical study is carried out on particle deposition in ducts with either convex or concave wall cavity.Results show that,if compared with smooth duct,particle deposition velocitiesVd^+increase greatly in ducts with wall cavities.More specifically,forτ+<1,Vd^+increase by about 2–4 orders of magnitude in the cases with the convex and concave wall cavities;forτ+>1,Vd^+grows relatively slower.Enhancement of particle deposition with wall cavities is caused by the following mechanisms,i.e.,interception by the wall cavities,expanded deposition area,and the enhanced flow turbulence.In general,addition of wall cavities is contributive for particle deposition,so it provides an efficient approach to remove particles,especially with small size,e.g.,PM2.5.Moreover,the convex wall cavity leads to a larger increment ofVd^+than the concave wall cavity.However,taking pressure loss into account,thoughVd^+is relatively lower,duct with the concave wall cavity is more efficient than that with the convex wall cavity.

Deposition of water-soluble inorganic ions in PM_(2.5) in a typical forestry system in Beijing,China

Background: Rapid economic development in China has resulted in an increase in severe air pollution in city groups such as the Beijing-Tianjin-Hebei Metropolitan Region. PM2.5(fine particles with an aerodynamic equivalent diameter of 2.5 μm or less) is one of the most important pollutants. The deposition process is an important way of removing particles from the air. To evaluate the effect of an urban forest on atmospheric particle removal, a concentration gradient method was used to measure the deposition velocities of water-soluble inorganics in PM2.5 in two national forest parks in Beijing, China. The following eight water-soluble inorganic ions in PM2.5 were investigated: sodium, ammonium, potassium, magnesium, calcium, chloride, nitrate, and sulfate.Methods: Samples were taken from two sites in Beijing from the 7 th to the 15 th May, 2013. The concentrations of water-soluble inorganic ions were analyzed with ion chromatography. We used the concentration gradient technique to estimate the deposition flux and velocity. To determine the relationships between leaf traits and particle accumulation, typical leaf samples from each selected species were studied using scanning electron microscopy.Results: The total deposition flux and total deposition velocity during the daytime were higher than those at night.Sulfate showed the biggest deposition flux and velocity at both study sites, whereas the other ions showed different trends at each site. Result from higher proportion of coniferous to broadleaved trees, the total deposition flux of the eight ions measured in Jiufeng National Forest Park was greater than that in Olympic Forest Park.Conclusions: The deposition velocity was affected by meteorological conditions such as wind speed, temperature,and humidity. The deposition velocity was also influenced by tree species. The surface of plants is an important factor influencing particle deposition. The results of this study may help in assessing the effects of forestry systems on particle removal and provide evidence for urban air pollution control and afforestation of urban areas.

Evaluation of Data Replacement Strategies for CASTNET Dry Deposition Modeling

The U.S. EPA （Environmental Protection Agency） established the CASTNET （Clean Air Status and Trends Network） and its predecessor, the NDDN （national dry deposition network）, as national air quality and meteorological monitoring networks. Both CASTNET and NDDN were designed to measure concentrations of sulfur and nitrogen gases and particles. Both networks also estimate dry deposition using an inferential model. The design was based on the concept that atmospheric dry deposition flux could be estimated as the product of a measured air pollutant concentration and a modeled deposition velocity （Vd）. The MLM （multi-layer model）, the computer model used to simulate dry deposition, requires information on meteorological conditions and vegetative cover as model input. The MLM calculates hourly Fa for each pollutant, but any missing meteorological data for an hour renders Vd missing for that hour. Because of percent completeness requirements for aggregating data for long-term estimates, annual deposition rates for some sites are not always available primarily because of missing or invalid meteorological input data. In this work, three methods for replacing missing on-site measurements are investigated. These include （1） using historical values of deposition velocity or （2） historical meteorological measurements from the site being modeled or （3） current meteorological data from nearby sites to substitute for missing inputs and thereby improve data completeness for the network＇s dry deposition estimates. Results for a CASTNET site used to test the methods show promise for using historical measurements of weekly average meteorological parameters.

Simulation and evaluation study of atmospheric aerosol nonsphericity as a function of particle size

Aerosol nonsphericity causes great uncertainty in radiative forcing assessments and climate simulations.Although considerable studies have attempted to quantify this uncertainty,the relationship between aerosol nonsphericity and particle size is usually not considered,thus reducing the accuracy of the results.In this study,a coupled inversion algorithm combining an improved stochastic particle swarm optimization algorithm and angular light scattering is used for the nonparametric estimation of aerosol nonsphericity variation with particle size,and the optimal sample selection method is employed to screen the data.Based on the verification of inversion accuracy,the variation of aerosol aspect ratio with particle size based on the ellipsoidal model in global regions has been obtained from Aerosol Robotic Network(AERONET)data,and the effect of nonsphericity on radiative forcing and dry deposition has been studied.The results show that the aspect ratio increases with particle size in all regions,with the maximum ranging from 1.4 to 1.8 in the desert,reflecting the differences in aerosol composition at different particle sizes.In radiation calculations,considering aerosol nonsphericity makes the aerosol cooling effect weaker and surface radiative fluxes increase,but hardly changes the aerosol absorption,with maximum differences of 9.22%and 22.12%at the bottom and top of the atmosphere,respectively.Meanwhile,the differences in radiative forcing between aspect ratios as a function of particle size and not varying with particle size are not significant,averaging less than 2%.Besides,the aspect ratio not varying with particle size underestimates the deposition velocity of small particles and overestimates that of large particles compared to that as a function of particle size,with maximum differences of 7%and 4%,respectively.

Dry deposition velocity of total suspended particles and meteorological influence in four locations in Guangzhou,China

Dry deposition velocity of total suspended particles （TSP） is an effective parameter that describes the speed of atmospheric particulate matter deposit to the natural surface. It is also an important indicator to the capacity of atmosphere self-depuration. However, the spatial and temporal variations in dry deposition velocity of TSP at different urban landscapes and the relationship between dry deposition velocity and the meteorological parameters are subject to large uncertainties. We concurrently investigated this relationship at four different landscapes of Guangzhou, from October to December of 2009. The result of the average dry deposition velocity is （1.49 ± 0.77）, （1.44 ± 0.77）, （1.13 ±0.53） and （1.82± 0.82） cm/sec for urban commercial landscape, urban forest landscape, urban residential landscape and country landscape, respectively. This spatial variation can be explained by the difference of both particle size composition of TSP and meteorological parameters of sampling sites. Dry deposition velocity of TSP has a positive correlation with wind speed, and a negative correlation with temperature and relative humidity. Wind speed is the strongest factor that affects the magnitude of TSP dry deposition velocity, and the temperature is another considerable strong meteorological factor. We also find out that the relative humidity brings less impact, especially during the dry season. It is thus implied that the current global warming and urban heat island effect may lead to correlative changes in TSP dry deposition velocity, especially in the urban areas.

A NEW DRY DEPOSITION VELOCITY PATTERN AND ITS PRACTICAL APPLICATION IN HIGH RESOLUTION REGIONAL ACID DEPOSITION MODEL

A new dry deposition velocity pattern (NDDVP) for the study of region-scale dry deposition processes is developed. The mean ratio between NDDVP and 1022 experimental data of dry deposi- tion velocity V_d is 1. 06±0.82. The result shows that NDDVP is well consistent with experimental data. Practical cases are forecasted by the high resolution regional acid deposition model (EM3) with both NDDVP and old V_d pattern. The maximum ratio between the central concentrations for SO4 can reach 2.4 only due to different V_d patterns. 3-D distributions of species concentrations and dry depositions forecasted by NDDVP are better than those by the old V_d pattern.

A database of modeled gridded dry deposition velocities for 45 gaseous species and three particle size ranges across North America

The dry deposition process refers to the flux loss of an atmospheric pollutant due to uptake of the pollutant by the earth’s surfaces.Dry deposition flux of a chemical species is typically calculated as the product of its surface-layer concentration and its dry deposition velocity(V_(d)).Field measurement based V_(d) data are very scarce or do not exist for many chemical species considered in chemistry transport models.In the present study,gaseous and particulate dry deposition schemes were applied to generate a database of hourly V_(d) for 45 gaseous species and three particle size ranges for two years(2016–2017)at a 15 kmby 15 km horizontal resolution across North America.Hourly V_(d) of the 45 gaseous species ranged from<0.001 to 4.6 cm/sec across the whole domain,with chemical species-dependentmedian(mean)values being in the range of 0.018–1.37 cm/sec(0.05–1.43 cm/sec).The spatial distributions of the two-year average V_(d) showed values higher than 1–3 cm/sec for those soluble and reactive species over certain land types.Soluble species have the highest V_(d) over water surfaces,while insoluble but reactive species have the highest V_(d) over forests.Hourly V_(d) of PM_(2.5) across the whole domain ranged from 0.039 to 0.75 cm/sec with median(mean)value of 0.18(0.20)cm s^(−1),while the mean V_(d) for PM_(2.5)–10 is twice that of PM_(2.5).Uncertainties in the modeled V_(d) are typically on the order of a factor of 2.0 or larger,which needs to be considered when applying the dataset in other studies.

Investigation of a solid particle deposition velocity in drag reducing fluids with salinity

Optimal and cost-effective drilling operations in extended-reach horizontal wells depend on efficient solid cuttings removal from the borehole.Several solids-suspended multiphase processes such as crude petroleum transportation,separation,and processing of oil and gas streams also require the efficient removal of these solids.The terminal settling velocity(Vts)of the solid particle is a vital parameter that controls the removal efficiency of these solids.In a drilling scenario when there is a hold on fluid cir-culation such as connection time,the accurate estimation of Vs provides the driller with time available to prevent solid deposition.In severe conditions,this can result in a stuck pipe,especially for extended-reach horizontal wells.In this work,both spherical and non-spherical particle deposition were experi-mentally investigated in several fluid rheology and salinity.Two concentrations(0.1 vol%and 0.05 vol%.)of partially-hydrolyzed polyacrylamide(PHPA)were used as a drag-reducing additive for water-based drilling mud.The PHPA drag-reducing fluid(reduced pressure loss)acts as a turbulence inhibitor.The PHPA polymer chain suppresses any turbulence in the flow,reducing the turbulent eddy viscosity.The effects of salinity(3 wt.%Nacl and 3 wt.%CaCl_(2) contamination)on solid particle settling velocity(Vs)in drag-reducing fluids were also investigated.Terminal velocity was achieved for all experiments and seemed to increase with increased diameter/sphericity.However,cases when this trend was not consistent were observed and therefore a new parameter of@(sphericity index×diameter)was pro-posed.V,increases with Q value for all cases.During drilling,PHPA also aids in sealing the fracture in the formation.With and without salt in the fluid,how lowering drag affected the settling velocity of solid particles(drill cuttings)could be observed.The settling velocity tests will be improved in drag-reducing PHPA solutions with the knowledge from this study.

Diurnal variation of ozone flux over corn field in Northwestern Shandong Plain of China

High concentration ground-level ozone(O3)has adverse effects on plant growth and photosynthesis.Compared to the O3concentration-based index,the O3flux-based(especially stomatal O3uptake)index has been considered the better criterion for assessing the impact of ozone on vegetation and ecosystems.This paper reports on a study of O3flux using the eddy covariance technique over a corn field in the Northwestern Shandong Plain of China.Diurnal variation of atmospheric O3concentration,deposition velocity and flux,and their relationships to environmental factors are analyzed.The results show that:(1)During the observation period(9 August–28 September,2011),there was a strong diurnal variation of O3concentration,with low(16.5 nL L?1)and high(60.1 nL L?1)O3mean concentrations observed around 6:30 and 16:00,respectively.Mean O3concentrations during daytime(6:00–18:00)and nighttime(18:00–6:00)were 39.8±23.1 and 20.7±14.1 nL L?1(mean±std),respectively.The maximum observed concentration was 97.5 nL L?1.The concentration was mainly affected by solar radiation and air temperature.(2)Whether daytime or nighttime,ground-level O3flux is always downward.The diurnal course of mean deposition velocity was divided into 4 phases:a low and stable process during nighttime,fast increasing in early morning,relatively large and steady changes around noon,and quickly decreasing in later afternoon.Daytime and nighttime mean deposition velocities were 0.29 and 0.09 cm s?1,respectively.The maximum deposition velocity was 0.81 cm s?1.The magnitude of deposition velocity was influenced by the corn growth period,and its diurnal variation was significantly correlated with global radiation and relative humidity.(3)O3flux was affected by variations of both O3concentration and deposition velocity,with mean O3fluxes-317.7 and?70.2 ng m?2s?1during daytime and nighttime,respectively.There was strong correlation between O3flux and CO2flux or latent heat flux.By comparing the deposition velocities of daytime and nighttime,we infer that stomatal uptake was probably the main sink of ground-level O3.

Ozone concentrations, flux and potential effect on yield during wheat growth in the NorthwestShandong Plain of China

Ozone（O3） concentration and flux（Fo） were measured using the eddy covariance technique over a wheat field in the Northwest-Shandong Plain of China. The O3-induced wheat yield loss was estimated by utilizing O3exposure-response models. The results showed that：（1） During the growing season（7 March to 7 June, 2012）, the minimum（16.1 ppb V） and maximum（53.3 ppb V）mean O3 concentrations occurred at approximately 6：30 and 16：00, respectively. The mean and maximum of all measured O3 concentrations were 31.3 and 128.4 ppb V, respectively. The variation of O3 concentration was mainly affected by solar radiation and temperature.（2） The mean diurnal variation of deposition velocity（V d） can be divided into four phases, and the maximum occurred at noon（12：00）. Averaged V d during daytime（6：00–18：00） and nighttime（18：00–6：00） were 0.42 and 0.14 cm/sec, respectively. The maximum of measured V d was about1.5 cm/sec. The magnitude of V d was influenced by the wheat growing stage, and its variation was significantly correlated with both global radiation and friction velocity.（3） The maximum mean F o appeared at 14：00, and the maximum measured F o was-33.5 nmol/（m^2·sec）. Averaged F o during daytime and nighttime were-6.9 and-1.5 nmol/（m^2·sec）, respectively.（4） Using O3 exposure-response functions obtained from the USA, Europe, and China, the O3-induced wheat yield reduction in the district was estimated as 12.9% on average（5.5%–23.3%）. Large uncertainties were related to the statistical methods and environmental conditions involved in deriving the exposure-response functions.

A HIGH RESOLUTION MODEL FOR CHEMICAL SPECIES EXCHANGE IN TROPOSPHERE

Based on the regional acid deposition model(RADM),a high resolution model for species exchange in the troposphere(EM3)is designed.EM3 differs considerably in the following 5 aspects from RADM.First,the vertical grid levels in the planetary boundary layer(PBL)are increased.Second,layered vertical eddy diffusivity patterns in the troposphere(TL)are considered.Third,layered horizontal eddy diffusivity patterns within TL is used.Fourth,new dry deposition velocity pattern including the effect of plant canopy layer(CL)vertical structure is adopted.Fifth,advective scheme of second-order moment conservation with less numerical diffusion is used.OSCAR 4 case is comparatively simulated with both EM3 and RADM.The results show that 3-D distribution laws of chemical species in whole TL are forecasted by EM3 better than by RADM.Under the same conditions,all ratios of the central concentrations simulated with both models in lower PBL are more than 1.8,the maximum can be more than 3.

A simulation study of airborne wear particles from laboratory wheel-rail contacts

Laboratory measurements of airborne particles from sliding contacts are often performed using a tri- bometer located in a ventilation chamber. Although knowledge of particle transport behavior inside the chamber is required because it can influence the analysis of measurements, this knowledge is lacking. A numerical model was built based on the same geometry as a pin-on-disc measurement system to explain particle transport behavior inside the chamber and to determine the deviation between real amounts of generated and measured particles at the outlet. The effect of controlled flow conditions on the airflow pattern and particle transport inside the chamber was studied for different experimental conditions. Cal- culations show that a complex airflow pattern is formed by the spinning disc, and that it differs for each rotational speed. Simulation results reveal that particle transport in the chamber is governed mainly by the airflow pattern. The deposition velocity in the chamber was estimated and the possibility that part of the generated particles would remain in the chamber was studied. This led to an approximate estima- tion of particle loss rate. A comparison between experimental and simulated results with respect to the particle mass flow rate close to the outlet yields a reference factor of 0.7, which provides an indication of the difference between measured and real values.