CFD–DEM simulation of particle deposition characteristics of pleated air filter media based on porous media model

In this study, the three-dimensional physical model of pleated air filtration media was simplified to porous media model, and the calculation parameters of porous media were obtained based on experimental data. The model of V-shaped pleated air filter media is constructed, the height of the media pleat is 50 mm and the pleat thickness is 4 mm, the pleat angle is 3.7°. The Hertz-Mindlin contact model was modified by Johnson Kendall Roberts (JKR) adhesion contact model. The deposition process of particles in media was simulated based on computational fluid dynamics (CFD) theory and discrete element method (DEM). Results show that the CFD–DEM coupling method can be effectively applied to the macro research of pleated air filter media. The particles will form dust layer and dendrite structure on the fiber surface, and the dust layer will affect the subsequent air flow organization, and the dendrite structure will eventually form a “particle wall”. The formation of the “particle wall” will prevent the particles from moving further in the fluid domain, which makes area of pleated angle become the “low efficiency” part about the particle deposition. Compared with area of pleated angle, the particles are concentrated in the opening area and the middle area of the pleated to agglomerate and deposit.

Sedimentary Processes and Depositional Characteristics of Coarse-grained Subaqueous Fans along Steep Slopes in a Lacustrine Rift Basin:A Case Study from the Dongying Depression,Bohai Bay Basin,China

Coarse-grained subaqueous fans are vital oil and gas exploration targets in the Bohai Bay basin,China.The insufficient understanding of their sedimentary processes,depositional patterns,and controlling factors restricts efficient exploration and development.Coarse-grained subaqueous fans in the Yong′an area,Dongying Depression,are investigated in this study.These fans include nearshore subaqueous fans,and sublacustrine fans,and their sedimentary processes,depositional patterns and distribution characteristics are mainly controlled by tectonic activity and paleogeomorphology.Nearshore subaqueous fans developed near the boundary fault during the early–middle deposition stage due to strong tectonic activity and large topographic subsidence.Early sublacustrine fans developed at the front of the nearshore subaqueous fans in the area where the topography changed from gentle to steep along the source direction.While the topography was gentle,sublacustrine fans did not develop.During the late weak tectonic activity stage,late sublacustrine fans developed with multiple stages superimposed.Frequent fault activity and related earthquakes steepened the basin margin,and the boundary fault slopes were 25.9°–34°.During the early–middle deposition stage,hyperpycnal flows triggered by outburst floods developed.During the late deposition stage,with weak tectonic activity,seasonal floods triggered hyperpycnal flows,and hybrid event beds developed distally.

Influence of UAV flight speed on droplet deposition characteristics with the application of infrared thermal imaging

A plant protection unmanned aerial vehicle(UAV)applied for spraying pesticide has the advantages of low cost,high efficiency and environmental protection.However,the complex and changeable farmland environment is not conductive to perform spray test effectively.It is therefore necessary to carry out spray test under controlled conditions.The current study aimed to illuminate the variation law of droplet deposition characteristics under different UAV flight speeds,and to verify the feasibility for applying infrared thermal imaging in detection of droplet deposition effects.A UAV simulation platform with an airborne spray system was established and an analysis program Droplet Analysis for dealing with water-sensitive paper was developed.The results showed that,when the flight speed was set at 0.3 m/s,0.5 m/s,0.7 m/s,0.9 m/s and 1 m/s,respectively,the droplet deposition density,droplet deposition coverage and arithmetic mean of droplet size D0 decreased as the UAV flight speed increased.On the contrary,the droplet diameter variation coefficient CV increased with the increase of UAV flight speed,resulting in the worse uniformity of sprayed droplet distribution as well.The results can provide a theoretical support for optimizing the spraying parameters of plant protection UAV,and demonstrate the practicability of infrared thermal imaging in evaluating the droplet deposition in the field of aerial spraying.

Mass-transport Deposits of the Upper Cretaceous Qingshankou Formation, Songliao Terrestrial Basin, Northeast China: Depositional Characteristics, Recognition Criteria and External Geometry

Extensive mass transport deposits（MTDs）, which form a significant component of the stratigraphic record in ancient and modern deep water systems, mostly distributed in the continental margin of ocean basins worldwide. To date, no large-scale MTDs have been found in Chinese terrestrial basins. Based on integrated analysis of the seismic, drilling, core and logging data, this article report MTDs have been found in Songliao terrestrial basin（SLTB）, Northeast China. During the depositional period of the Upper Cretaceous Qingshankou Formation, slope break of lacustrine basins was an ideal discharge place for gravity depositions. Regional sedimentary study of MTDs reveals that Cretaceous-age MTDs in SLTB were deposited in slope-break environments by slide, slump and debris flow, and MTDs were mixed with little turbidite simultaneously. Besides the massive aspect, key features of MTDs are the common presence of deformational structures or softsedimentary deformation, floating shale clasts, boudins, microfaults, distortion beddings, rotated sand debris. Detailed mapping of two three-dimensional（3-D） seismic surveys acquired in Yingtai（YT） and Haituozi（HTZ） areas reveals that MTDs are characterized by chaotic, mounded, and transparent seismic reflection. Growth fault, slope gully and geomorphology of the slope break greatly influenced the sedimentary process and external geometry of MTDs, and as a consequence, MTDs in SLTB exhibit classic fan-like geometry and some special（non-fan-like） external geometry. Furthermore, fanlike MTDs can be divided into three subcategories, including isolated fan, mother-son fan and stacked fan. Non-fan-like MTDs can be divided into two subcategories, strip-like MTDs and faulted-pit MTDs. A new sedimentary model has been built for MTDs in SLTB. MTDs have become a new exploration and development target in the SLTB.

Laboratory-scale investigation of the material distribution characteristics of landslide dams in U-shaped valleys

Material distribution characteristics during sliding and depositing is particularly significative to investigate the internal structure and spatial variation of landslide dams,which are fundamentally determining the mechanical and hydraulic behavior and the susceptibility to cause dam failure.However,limited by longevity shortages and special geographic environments,the material distribution characteristics and their formation mechanisms are difficult to observe in the field.Therefore,an experimental apparatus modeling a landslide dam was developed in this paper,designing three sampling methods with two valley states.The internal deposit characteristics,void ratio variation and relative content of the particle size range(PSR)were analyzed,and the mechanics of deposit structure were also delicately ascertained.The results indicate that granular material deposited in valley shows a structure of inverse grain size accumulation in both vertical and horizontal directions,exhibiting spatial variability of particle gradation and void ratio.The characteristic PSR decreases from 22-30 mm in the two-dimensional state to 10-14 mm in the threedimensional state.Vibration excitation and vibration sieve are the intrinsic mechanisms of granular flow segregation,intrinsically inducing the formation of inverse grading deposit structures.Consequently,spatial variability in size is mainly trig gered by segregation,whereas coarse particle content and deposition boundaries merely exacerbate the difference degree.

Types, Metallogenic Environments and Characteristics of Temporal and Spatial Distribution of Copper Deposits in China

Based upon a comprehensive study of 123 copper deposits in China. this paper reaches the following conclusions: 1. The crust in China was solidified pretty late; with the accretion of the plate, the copper mineralization moved towards its margin in space and became successively younger in age. 2. The major copper ore types ever found in the world have mostly been discovered in China, in which the porphyry type seems to be the most important and the massive sulfide type in the transitional bed between marine clastic and carbonate rocks is clearly defined. 3. Carbonate strata are widespread in China and their deposition lasted for a long geological period, so the proportion of copper deposits occurring in them is large as compared with other parts of the world. 4. Seven metallogenic epochs can be recognized, in which the Mesozoic one plays the leading role and the middle(late) Palaeozoic and Cenozoic ones are next in importance. Mineralization was comparatively simple in the early geological period. and became diversified later on. In the early epochs copper deposits related to basaltic magmatism and metamorphosed marine sediments predominated, whereas in the later epochs those related to granitic magmatism and continental sedimentation were dominant. 5. There exist in China thirteen metallogenic provinces, of which the Lower Yangtze downwarping belt, Sanjiang fold system, Jiangnan axis and Xikang-Yunnan axis are of greater significance. 6. The crustal mobility in China was rather pronounced, the polycyclic evolution of the crust has resulted in such obvious phenomena as the inheritance of mineralization, the coexistence of various types and the superposition of different genetic types.

The Characteristics of Ore-Controlling Structure in Baoshan Cu-Pb-Zn Polymetallic Deposit,Hunan Province

The Baoshan Cu-Pb-Zn polymetallic deposit is lied in the central Nanling mineralization zone,and belongs to the junction area of the Chenzhou-Linwu fault zone and the Leiyang-Linwu fault zone.It is a significant part of Nanling polymetallic deposit belt.The outcropping stratas consist of upper Devonian Shetianqiao,Xikuangshan Formation,Lower Carboniferous Menggong’ao,Shidengzi,Ceshui,and Zimenqiao Formation.Igneous rocks in the Baoshan ore area mainly comprise granodiorite porphyry.Furthermore,the radio isotopic age ranges from 123 Ma to 183 Ma,belonging to the early to middle Yanshanian.

Structural Characteristics of the Suoluogou Gold Deposit in Muli County, West Sichuan Province

The Suoluogou gold deposit in Muli County of Sichuan Province is located in the southern section of the Ganzi- Litang suture zone （Figs. la, b）, which is the largest gold deposit discovered in this suture zone in recent years. At present, the exploration of the Suoluogou gold deposit is still in progress, and the amount of resource is increasing.

Geochemistry Characteristics of Granodiorite Porphyry in the Degongniuchang Copper Deposit, Muli, Sichuan Province, China

1 Introduction 1The Sanjiang region in SE Tibet Plateau and NW Yunnan is known to have formed by amalgamation of Gongwanaderived continental blocks and arc terranes as a result of oceanic subduction followed by continental

DC Characteristics of Lattice-Matched InAlN/AlN/GaN High Electron Mobility Transistors

Lattice-matched InAlN/AlN/GaN high electron mobility transistors (HEMTs) grown on sapphire substrate by using low-pressure metallorganic chemical vapor deposition were prepared, and the comprehensive DC characteristics were implemented by Keithley 4200 Semiconductor Characterization System. The experimental results indicated that a maximum drain current over 400 mA/mm and a peak external transconductance of 215 mS/mm can be achieved in the initial HEMTs. However, after the devices endured a 10-h thermal aging in furnace under nitrogen condition at 300 ℃, the maximum reduction of saturation drain current and external transconductance at high gate-source voltage and drain-source voltage were 30% and 35%, respectively. Additionally, an increased drain-source leakage current was observed at three-terminal off-state. It was inferred that the degradation was mainly related to electron-trapping defects in the InAlN barrier layer.

The Mechanism of Structural Control of Ore Formation and Geochemical Characteristics in the Massive Sulfide Deposits of the Wushan Copper Ore Field,Jiangxi

The ore-controlling mechanism of the bedding fault system in the massive sulfide deposits of the Wushancopper orefield may be generalized as the control of ore deposition by optimum surface in an ore-formingstructural trap. The mechanism has three major features: (1) timing of mineralization; (2) positioning of hostformation; and (3) dependence of ore-controlling structure on properties of rocks. The 'optimum surface' is adivisional structural plane which marks obvious difference in physical, chemical and mechanical properties andis favorable for mineralization. It is also a unity of structures. lithofacies and orebodies. The structural and geochemical characteristics of the ore deposits indicate the migration trend of the ma-jor characteristic clements in the ore-controlling fault belt: elements with a small radius (Si, Fe, Mg and Al)moved towards and concentrated at the center of the belt while large-radius ones (Ca, K and Na) were remotefrom the center.

Geological characteristics and genesis of subbottom pinnoite deposit of Da Qaidam salt lake in Qaidam Basin

Da Qaidam salt lake is known for its both liquid and solid boron resource.Data from previous investigation of the Da Qaidam salt lake provided a comparable framework for this study that focused on investigating the section beneath the bottom of the perennial salt lake,including the timing,

Investigations on pool boiling critical heat flux, transient characteristics and bonding strength of heater wire with aqua based reduced graphene oxide nanofluids

In the present work, the pool boiling critical heat flux, transient heat transfer characteristics, and bonding strength of thin Ni-Cr wire with aqua based reduced graphene oxide(r GO) nanofluids are experimentally studied. Results indicate:(i) the critical heat flux(CHF) of 0.01, 0.05, 0.1, 0.2, and 0.3 g·L^(-1) concentrations of r GO-water nanofluids varies from 1.42 to 2.40 MW·m^(-2);(ii) the CHF remains same for the tested samples during transient heat transfer studies and(iii) a constant value of CHF upto 10 tests when the nanocoated Ni-Cr wire is tested with DI water and deterioration occurs beyond this which implies a chance of peel off of r GO layer below the critical coating thickness.

Geology and fluid inclusion characteristics of Qilishan gold deposit in Zhaoyuan of Shandong,China

The Qilishan gold deposit is located in the southern Zhaolai gold ore belt in the northwestern Jiaodong region.A total of seven gold ore bodies have been found in the mining area.Linglong gneissic biotite granite and the NE trending Lingbei fracture control the output and distribution of the gold deposit.The ore bodies with veined or irregular shape occur in the structural alteration zone.The ore bodies of different sizes are NE trending and SE dipping.The constituent minerals of the ores mainly include pyrite,chalcopyrite,native gold,electrum,argentite,matildite,hematite,quartz and calcite.The ores are characterized by metasomatic dissolution structure,as well as veined and brecciated structures.The ore-forming process is divided into four stages,namely quartz-,pyrite-,polymetallic-and carbonate stages.Study on fluid inclusion shows that the deposit is composed of gas-liquid two-phase inclusions （Ⅰ） and three-phase inclusions containing CO2 （Ⅱ）,and that the former dominates.The homogenization temperature is 259.6℃-373.7℃ ; the salinity of three-phase inclusions containing CO2is 5.77%-9.84% （NaCl） ; the salinity of gas-liquid two-phase inclusions is 6.58%-8.54% （NaCl） ; and the estimated ore-forming pressure is 55.2-82.2 MPa.According to the nonlinear relationship between the depth and pressure of the fluid in the fracture zone,the ore-forming depth of the Qilishan gold deposit is calculated as 5.95-7.14 km.It is preliminarily determined that the deposit is a mesophilic and hypothermal gold deposit.

Metallogenic Characteristics of the Major Type Deposits in Southeast Asia

1 Introduction The Southeast Asia is endowed with a diversity of mineral resources(Khin Zaw et al.,2014).Tin,copper,nickel,bauxite,chromium and potash resources are widely distributed in the Southeast Asia,show considerable economic significance,have obvious complementarity to China,and is paid wide attention by Chinese geologists and mining industry in recent years.

Mineral Chemical Characteristics of Gabbro-diorite for Shulouqiu Uranium Deposit in Northern Guangdong, China: Constraint on the Magmatic Source

1 Introduction The uranium deposits related with Indosinian and Yanshanian granite have provided the abundant resource of uranium during the past several decades in China.The deposits are mainly distributing in the Guidong granite

Ore-controlling Characteristics of Synchronous Faults of Dongshengmiao Polymetallic Sulfide Deposits in Inner Mongolia

1 Introduction The Dongshengmiao deposit is a super-large Zn-Pb polymetallic sulfide deposit which occurring in the Langshan-Zhaertaaishan metallogenic belt,and located in the western margin of the North China Platform.The ore-bodies of Dongshengmiao deposits are mainly hosted in the second Formation of Langshan Group.There are some studies on the geological characteristics(Peng et al.,2004),geological and

Tectono-geochemical Characteristics at the level 1584m in Huize Zinc-Lead Deposit,Yunnan Province

1 Introduction The Huize Zn-Pb district is located in the tectonic composite position,became one of the important production areas of zinc,lead and germanium in China.In the Huize lead-zinc deposit,the interlayer faults are most

Studies on Characteristics of Fracture Lithofaciesin Wenxipo W-Cs-Rb Polymetallic Deposit,Hainan Province,China

1 Introduction Wenxipo W-Cs-Rb polymetallic depositis located in Fengshou rubidium-cesium polymetallic prospecting area in Danzhou City,Hainan Province,China.The hornstone facies,a thermal metamorphic facies,