Development of Steel Slag-Based Solidification/Stabilization Materials for High Moisture Content Soil

To solve the problems of high moisture content,high viscosity,and poor engineering mechanical properties of soil,this paper using with steel slag(SS)and desulfurization ash(DS)as initial raw materials,realizing the coop-erative treatment of solid waste and solidification of silt soil.The synergistic utilization of SS and DS can reduce the production cost of curing agent and promote its own consumption.According to blended cement of various SS contents and inspected compressive strength performances,the most suitable raw materials ratio was selected.The best formula for this curing agent is cement:steel slag=3:7 with 5%DS,and its 28-day compressive strength can reach 30 MPa.The experiment shows that the effect of DS and Na_(2)SO_(4) reagent with the same quality on early compressive strength improvement of cement and SS system is not much different.In this study,the mineral composition and microstructure of different gel system blocks were characterized by XRD,SEM and EDX,and a large number of webbed structures were found in the SEM test,which was not seen in previous studies.Besides,unconfined compressive strength(UCS),water resistance,and toxic characteristic leaching procedure(TCLP)were used to evaluate silt solidified soil properties.The results demonstrated that the solidified silt could meet not only the standard of general subgrade;but also has a partial stabilization effect of heavy metal ions.

A Cloud Framework for High Spatial Resolution Soil Moisture Mapping from Radar and Optical Satellite Imageries

Soil moisture plays an important role in crop yield estimation,irrigation management,etc.Remote sensing technology has potential for large-scale and high spatial soil moisture mapping.However,offline remote sensing data processing is time-consuming and resource-intensive,and significantly hampers the efficiency and timeliness of soil moisture mapping.Due to the high-speed computing capabilities of remote sensing cloud platforms,a High Spatial Resolution Soil Moisture Estimation Framework(HSRSMEF)based on the Google Earth Engine(GEE)platform was developed in this study.The functions of the HSRSMEF include research area and input datasets customization,radar speckle noise filtering,optical-radar image spatio-temporal matching,soil moisture retrieving,soil moisture visualization and exporting.This paper tested the performance of HSRSMEF by combining Sentinel-1,Sentinel-2 images and insitu soil moisture data in the central farmland area of Jilin Province,China.Reconstructed Normalized Difference Vegetation Index(NDVI)based on the Savitzky-Golay algorithm conforms to the crop growth cycle,and its correlation with the original NDVI is about 0.99(P<0.001).The soil moisture accuracy of the random forest model(R 2=0.942,RMSE=0.013 m3/m3)is better than that of the water cloud model(R 2=0.334,RMSE=0.091 m3/m3).HSRSMEF transfers time-consuming offline operations to cloud computing platforms,achieving rapid and simplified high spatial resolution soil moisture mapping.

Effect of pellet die diameter on density and durability of pellets made from high moisture woody and herbaceous biomass

Densified products produced from pellet mill are commercially used as a commodity type product for energy applications that are transported nationally and internationally.The quality of the pelletized biomass produced depends on the process variables such as die diameter,length to diameter(L/D)ratio,die speed,preheating,and steam conditioning;and feedstock variables such as feedstock type,moisture content,and particle size and shape.In the present study,pelleting tests were conducted with both woody(i.e.,lodgepole pine and pinyon-juniper)and herbaceous(i.e.,corn stover,wheat straw,and energy sorghum)biomass.A high level of feedstock moisture content of 33%(w.b.)was selected,while the die speed and preheating temperature process variables were kept at 60 Hz(380 rpm)and 70
C.Results indicated that during the pelleting and cooling process,an approximate 10–13%(w.b.)moisture loss in both the woody and herbaceous biomass was observed.The high moisture pellets produced were further dried in a laboratory oven at 70
C for three hours to reduce the moisture content of the pellets to<10%(w.b).The dried pellets were then evaluated further for other quality attributes including unit,bulk,and tapped density;and durability.The pellets that resulted in the highest unit,bulk,and tapped densities following this process were the herbaceous biomass corn stover(e.g.,>1133,>580,>620 kg/m3)and the woody biomass lodgepole pine(e.g.,>1037,>568,>641 kg/m3),respectively.In the case of durability for the 8 mm diameter pellets,wheat straw and corn stover recorded a maximum of about 96%,respectively,while the lodgepole pine and pinion juniper recorded a maximum of>96%,respectively.

Experimental Study of High Moisture Content Gas Flow Across a Cylinder at Moderate Reynolds Numbers

The Nusselt number for cross flow of a mixture of air and vapor over a cylinder was measured at moderate Reynolds numbers (30007000) for temperatures from 300℃ to 700℃ and for vapor mass fractions of 0.180.35. Results are also presented for a set of three cylinders aligned perpendicular to the flow for the same range of conditions. The effect of the vapor concentration and temperature on the convection coefficients was investigated to develop a modified Zhukauskas correlation. The results show that the Nusselt number increases as the moisture content increases and that the increase is more than could be accounted for by typical models for the property variations of mixtures. The exponent of the vapor concentration term in the modified correlation is 0.145 for the entire data set indicating the importance of the property variation due to the moisture content.

Effect of variety and seed dressing on emergence of high-oleic peanut under low temperature and high soil humidity conditions

Low temperature coupled with high soil moisture during sowing to emergence generally results in poor peanut stand,thereby posing a non-negligible threat to peanut production in north and northeast China.Five high-oleic(HO)peanut cultivars and 4 seed dressing treatments capable of controlling several diseases and insect pests along with untreated checks were used to find the best combinations to cope with the dual stresses during sowing to emergence period.High broad-sense hereditability estimates of seedling emergence indicated great potential for genetic improvement of this trait.Analysis of variance in the split-plot experiment showed that the main effects of variety and seed dressing and their interaction on seedling emergence were significant.Seed dressing treatments increased seedling emergence percentage by 2.09–35.00 percent points.Four of the 5 HO peanut cultivars yielded satisfactory results.For Huayu 665,Huayu 668 and Huayu 965,Huweisanbao may be the best option;for Huayu 962,Weilidan was highly acceptable.These combinations will be evaluated further in multiple environments before large-scale extension.

An Experimental Study of Composite Columns Filled with Eucalyptus nitens Timber under Axial Compression

Eucalyptus nitens(E.nitens)has been much used for producing paper but also shows promise for structural applications.In this study,static compressive tests were undertaken to examine its suitability to be used in an innovative composite column.The composite column was comprised of a rectangular steel tube with E.nitens timber infill.The nonlinear compressive behaviour of the composite column filled with E.nitens wood for both dry and wet conditions was examined.The same tests on rectangular steel tubes and bare dry and wet E.nitens samples were also undertaken as a comparison.For samples with different conditions,the ultimate capacity was evaluated and the effect of each condition on the compressive behaviour of the composite column was clarified.The steel tubes showed greater ductile behaviour,and more ductility was found in the wet samples.The steel tubes with E.nitens timber infill samples exhibited a greater linear elastic range connected with higher maximum loads,while the bare timber samples could support only lower maximum loads.The results from this research were promising for the use of rectangular steel tubes with E.nitens timber infill in structural applications.

A Cost Analysis of Mobile and Stationary Pellet Mills for Mitigating Wildfire Costs

A comparison of traditional and mobile wood pellet mills found that mobile systems had higher production costs. Wildfire suppression costs have consistently exceeded British Columbia’s budget set for such activities. Pelletization of excess wood for bioenergy applications has been proposed as a possible method of reducing the overall costs of fighting wildfires. In this study, a traditional pellet mill produces wood pellets from new, marginal feedstocks for $182.24 ± 24.47 and a mobile pellet production system produces wood pellets for $402.71 ± 24.18 . The traditional pellet mill produces 90,000 with harvest residues being collected in the forest, transported to the pellet mill, dried, chipped, pelletized and then stored. The mobile system collects harvest residues from the forest, transports them to the forest landing where the trailer-mounted mobile pellet system is established and is then ground, pelletized and dried if needed. The mobile system uses a novel high moisture pelletization system and harvest residues to heat the biomass dryer used in the system. The mobile pellet system requires 22 systems to produce 90,000 and each system should relocate 9 times in a year to minimize production costs related to feedstock quality and scarcity. These mobile pellet systems can allow increased forest management in forest areas at high risk for wildfires and reduce the cost of suppressing wildfires in treated areas.

Ancillary Impacts of Harvest Residue Pelletization

This paper analyzes the implications on employment, taxation, and wildfire fuel reduction costs when using mobile pellet mills to remove biomass and reduce wildfire fuels. Wildfire suppression costs in British Columbia have exceeded the set budget in 9 of the last 10 years and the province has only reduced the fuel load on a fraction of the high-risk hectares. Using a novel high-moisture mobile pellet mill allows the production of 89,000 tonnes of wood pellets each year for a price of $293 . Each tonne produced also provides $546 in additional benefits from employment, taxation, and reductions in the cost to perform fuel treatments. The presented research found that 11 employees are needed to operate a mobile pellet mill, with total employment of 242 for 22 systems across BC. The assessed system can also avoid $5.5 million in employment insurance payments. The 22 systems also provide $323,000 in taxable profits and $524,000 from income taxes from employees. Fuel treatment with the researched systems costs $1112 . A cost-benefit analysis shows that the system provides $2.97 in benefits for every dollar invested.

Interaction Between Typhoon Vicente(1208) and the Western Pacific Subtropical High During the Beijing Extreme Rainfall of 21 July 2012

The heaviest rainfall in recent six decades fell in Beijing on 21 July 2012, reaching a record of 460 mm within 18 h. This rainfall was a typical remote precipitation event related to Typhoon Vicente（1208）.Observational analysis indicates that Vicente influenced distant heavy rainfall by transporting water vapor northward to the Beijing area. This moisture transport was mainly driven by the interaction between Vicente and the western Pacific subtropical high（WPSH） associated with the formation of a low-level southeasterly moisture channel. A set of numerical sensitivity experiments were performed with prescribed typhoons of different intensities to investigate the interaction between Vicente and the WPSH and its effects on this rainstorm process. The results indicate that the WPSH interacting with typhoons of different intensities may exert varying degrees of influence on the development of a southeasterly moisture channel, resulting in a change in rain rate and location over the Beijing area. Specifically, in the presence of an enhanced typhoon,the WPSH shows remarkable withdrawal to the east, which is favorable for a northward extension of the southeasterly moisture channel, thereby increasing moisture supply for the rainstorm. The WPSH tends to stretch westward in a zonal pattern if the typhoon is weakened or removed, hindering the northward extension of the moisture channel. Thus, the rainfall area may be expected to expand or contract, with corresponding increases or decreases in rain rate over the Beijing area with a strengthened or weakened typhoon, respectively.