资源目录
压缩包内文档预览：(预览前20页/共105页)
编号：30581330
类型：共享资源
大小：5.90MB
格式：ZIP
上传时间：2019-12-12
上传人：机****料
认证信息
个人认证
高**（实名认证）
河南
IP属地：河南
50
积分
- 关 键 词：
-
XY
岩心
钻机
升降机
设计
- 资源描述：
-
XY-4岩心钻机升降机的设计,XY,岩心,钻机,升降机,设计
- 内容简介：
-
Analysis of causes of casing elevator fractureLuo Faqiana, Lu Shuanlua,b,*, Li Helinc, Qin Changyic, Zhou Jiea,Tang Jipinga, Chi JunaaTarim Oil Field, Korla, Xinjiang 841000, ChinabChina University of Petroleum, Changping, Beijing 102249, ChinacTubular Goods Research Center of CNPC, Xian, Shaanxi 710065, ChinaReceived 8 April 2005; accepted 12 March 2006Available online 7 September 2006AbstractA fracture accident occurred with a 244.5 mm350 ton casing elevator and a traveling hook during casing runningdown. This paper gives an investigation of this accident, and analyzes the causes based on fracture surface examinationand material tests. Some simulation tests are performed in order to validate the fracture mechanism. It is concluded thatthe casing elevator fracture originated from quenching cracks caused by surface carburization. Calculations of the fractureload acting on the casing elevator showed that the casing elevator broke first, resulting in hook fracture.? 2006 Elsevier Ltd. All rights reserved.Keywords: Casing elevator; Fracture; Quenching crack; Surface carburization1. BackgroundThe 244.5 mm casing was running down as the well depth reached 3702 m. The weight of the casing stringwas 215 ton with the 331 lengths of casing. The upper casing elevator and hook broke as the lift load of thecasing elevator reached 170 ton after the lower casing elevator was taken apart from the well head for runningdown a new length of casing. The casing elevator broke at the left hanging ear position, and the hook broke upinto many pieces 1. The right link fell down on the front of the slope road, and the left link was (left) hangingon the neck of the hook by a length of 12.5 mm diameter steel wire rope. This accident caused a delay of thewell completion and was submitted for failure analysis at TGRC.2. Macrofractography and fractography2.1. MacrofractographyThe casing elevator broke at the left hanging ear position, and the fracture morphology is shown in Figs. 1and 2. Area A shows the original cracks with a depth of 65 mm, taking about 1/3 of the total fracture. It pre-1350-6307/$ - see front matter ? 2006 Elsevier Ltd. All rights reserved.doi:10.1016/j.engfailanal.2006.03.012*Corresponding author.E-mail address: lusl (L. Shuanlu)./locate/engfailanalEngineering Failure Analysis 14 (2007) 606613sents a yellow-gray appearance and shows corrosion at the edge and then a tempered color after cleaning.There was an obvious radiating band that contracted to the right lower corner of the fracture from wherethe crack originated (Fig. 1). Area B was severely corroded and produced some original cracks which hadnot extended. Area C was the extension from Area A and was the final fracture presenting a rougher fracturesurface than that of Area A. The angle between A and C was about 30?. At the lower edge of the fracture theplastic deformation area was 40 mm in length and 10 mm in width. Many cracks were found on the left hang-ing ear surface of the casing elevator (Fig. 3) by NDT. The cracks were mostly concentrated on the bevel posi-tion at the right lower corner of the fracture.The fracture features showed that Areas A and B were original cracks, and the original crack in Area Aextended first, causing the fracture.Fig. 1. Fracture morphology and position of the casing elevator.Fig. 2. Fracture appearance.L. Faqian et al. / Engineering Failure Analysis 14 (2007) 6066136072.2. FractographyA big difference appeared in micro-morphology between Areas A and C (Fig. 4) in the scanning electronmicroscope. The micro-morphology close to the crack origin of Area A was intergranular interface + cleav-Fig. 4. The micro-morphology of the boundary between Areas A and C.Fig. 5. The micro-morphology of the extension of Area A.Fig. 3. Cracks on surface at right lower corner of the fracture.608L. Faqian et al. / Engineering Failure Analysis 14 (2007) 606613age + secondary cracks, and the micro-morphology was mainly intergranular at the right lower corner of AreaA. The intergranular micro-morphology decreased with distance from the original crack. The micro-morphol-ogy far away from the crack origin in Area A was intergranular + cleavage + secondary cracks (Fig. 5). Themicro-morphology in Area C was cleavage + dimples (Fig. 6).3. MetallographyIt was found that the original cracks extended along an intergranular interface, and there were intergran-ular cracks near to the fracture origin. The cracks presented a gray colour, and the surrounding microstructureof the cracks at the fracture was the same as in other areas (Fig. 7). The crack features were indicated to bequenching cracks according to metallography, macrofractography and fractography.There was a carburized layer 0.44 mm in depth on the casing elevator hanging ear surface. The carburizedlayer was very clear (Fig. 8) after treatment in a vacuum furnace at 900 ?C. The hardness distribution in thecarburized layer is shown in Fig. 9.The cracks on the surface at the right lower corner of the fracture also extended along intergranular inter-faces, and the crack depth corresponded with that of the carburized layer (Fig. 10).It is obvious that many cracks were generated on the elevator surface due to carburizing and quenching,especially at the edge of the hanging ear. The original cracks on the fracture were actually part of thesequenching cracks.Fig. 6. The micro-morphology of Area C.Fig. 7. The crack and micro-structure near the edge of Area A 400.L. Faqian et al. / Engineering Failure Analysis 14 (2007) 6066136094. Material tests4.1. CompositionThe material of the casing elevator was 20SiMn2MoVA.4.2. Mechanical propertiesThe mechanical properties are shown in Table 1.Fig. 8. The micro-structure of the carburized layer 125.Fig. 9. Hardness distribution in carburized layer.Fig. 10. The micro-morphology of cracks on surface and micro-structure at right lower corner of the fracture 125.610L. Faqian et al. / Engineering Failure Analysis 14 (2007) 606613The surface hardness of the carburized layer was 60.060.5 HR45N, equal to 54.555.0 HRC. Section hard-ness was 44.546.5 HRC. The former is 10 HRC higher than the latter.5. Simulation testsIn order to validate the nature of the fracture, some supplementary simulation tests were carried out in thelaboratory on specimens from the broken casing elevator.5.1. Temper testThe temper test for the CVN specimen was done for 5 h at 230 ?C according to the temper specification ofthe casing elevator, and it was found that the CVN specimen was grass yellow which was similar to that onArea A of the casing elevator fracture.5.2. Fracture section oxygen atom analysisFracture Auger spectral energy meter and PHI-600 scanning spectral energy meter analysis were carried outon Areas A and C of the fracture and the CVN specimen tempered at 230 ?C. Oxygen atom concentration atArea A of the fracture was 60%, and oxygen atom concentration was 53% on the CVN specimen tempered at230 ?C. The oxygen atom concentration at Area C of the fracture was only 26%.5.3. Oxide structure analysisPer analyzing by PHI-540 X-ray electron energy chart instrument, the oxide on Area A of the fracture andthe CVN specimen fracture was Fe2O3, and the oxide on Area C was Fe2O4.The simulation test results indicated that the oxide and its structure on Area A of the fracture were similarto that of the CVN specimen fracture tempered at 230 ?C. The result above could confirm that Area A of thefracture was generated after quenching and before tempering.6. Discussion6.1. Fracture accident process analysisA further analysis of the accident sequence gives us more understanding of this accident.During the lifting process, the hook carried the load of the casing elevator and the string through two linksthat were connected with the left and right hanging ears, and the hook with the 12.5 mm diameter wire ropes(Fig. 11). The assumptions as well as the possibilities about fracture processes are as follows:6.1.1. Supposing two hook ears broke firstIf the hook ears broke first during the lifting process, then the wire ropes that were linked with the neck ofthe hook would have also broken because the strength of the 12.5 mm wire ropes were weaker than that of thecasing elevator ears. The casing elevator ears were not tensioned by the links in this case. So it would not havebroken. Thus, this assumption is not consistent with the facts, and is not correct.6.1.2. Supposing right hook ear broke firstThere would have been only one link to load the casing elevator if the right hook ear broke first. The frac-ture would take place from the weak position in this case. If the strength of the left hook ear was weaker thanTable 1Mechanical propertiesItemYield strength (MPa)Tension strength (MPa)Elongation (%)Charpy absorbed energy (J)Mechanical property1144143315.531L. Faqian et al. / Engineering Failure Analysis 14 (2007) 606613611that of the left casing elevator ear, then the left hook ear would have broken first, and it was vice versa. It wasimpossible that both of them broke at the same time in this assumption. In fact, both the casing elevator andhook actually broke in the accident. So this assumption is not correct.6.1.3. Supposing left hook ear broke firstIf the left hook ear broke first, then the left casing elevator ear would not have broken because it was notloaded by the hook in this situation. So this assumption is impossible.6.1.4. Supposing left casing elevator ear broke firstThe right single link load would act on the casing elevator if the left casing elevator ear had brokenfirst, and then the hook was forced to break up. The original cracks on the left casing elevator ear wouldextend quickly to fracture when the elevator suffered over load. The left link was still suspended on theneck of the hook through the 12.5 mm wire rope because it was not over loaded after the left casing ele-vator ear broke.The hook broke due to its strength, which was weaker than that of the right casing elevator ear suspendedfrom the right single link. The wire rope hanging the right link was tensioned to failure as the traveling blockrose continuously after the hook broke, and then the right link fell down to the front of the slope way. Thisprocess is well matched with the actual conditions. In addition, there was a plastic deformation area hit by theleft link at the lower edge of the casing elevator fracture. It indicated that the hook was not broken when theleft casing elevator ear broke.6.2. Casing elevator break load analysisThe casing elevator broke as the load was up to 170 ton during lifting, and the left and right casing elevatorear would bear 85 ton load, respectively, in this situation. 107.2 ton load would be laid on the left and rightcasing elevator ear, respectively, according to the total load of 214.4 ton as 331st piece of casing was run. Theactual fracture load acting on the left and right casing elevator ears should be more than 107.2 ton at leastinstead of 85 ton, resulting in fracture, according to the above. Extra tension, or impact load worked onthe casing elevator during fracture. The load acting on the casing elevator will be increased because of liftingacceleration as the casing string was lifted by the upper casing elevator 2.Fig. 11. Installation of casing elevator and links and hook.612L. Faqian et al. / Engineering Failure Analysis 14 (2007) 6066136.3. Effect of original cracks on load capability of the casing elevatorThe weaker position of the casing elevator is at its ear circumference edge connected with the link duringstring lifting, and the fracture position is just at the critical section. The left casing elevator ear would have notbroken even though 170 ton was acting it if there were no original cracks on it according to the casing elevatorstrength 3. The original crack area is about 1/3 of the critical area, but the fracture load is only 1/2 of therated load. It indicated that the cracks in the critical section not only reduce the area of loading, but also causesevere stress concentration that makes its carrying capacity decrease.6.4. Analysis on causes of quenching cracksThere were severe quenching cracks on the casing elevator before the fracture accident. The quenchingcracks were due to carburizing in the surface layer of the casing elevator. The cause of carburizing is thatthe carbon content of carbon potential was too high in the furnace during heating for quenching. The surfacelayer material of the casing elevator is determined as high carbon alloy steel with Si, Mn, Mo, and V aftercarburizing, and the quenching heat temperature in carburizing layer should be much lower than that of20SiMn2MoVA steel. The casing elevator is designed to load the string capacity, and the carburizing is notallowed. So quenching heat temperature was determined according to 20SiMn2MoVA steel, and quenchingof the carburized layer in accordance with the quenching temperature designed for 20SiMn2MoVA steel mustform a microstructure with high hardness, and brittle properties, and easily generate quenching cracks. So thecarburized layer is very harmful. The degree of quenching cracks is also related to the structure shape becausethere were many dense cracks on the bevel edge at the right lower corner of the casing elevator ear. The ori-ginal crack depth of 65 mm on the fracture originated from the bevel edge because there was severe stress con-centration at this position.7. Conclusion(1) The casing elevator left ear broke at the moment before the hook fracture.(2) The main cause of the casing elevator fracture was that there were quench cracks of 65 mm in depth atthe critical section of the casing elevator due to carburizing.References1 Shuanlu Lv, et al., Cause analysis on traveling hook fracture. Oil field machinery; No. 4 of 2006.2 Shuaqnlu Lv, et al., Analysis and research on causes of J55 CSG jump out. Eng Fail Anal; 2005.3 Specification for drilling and production hoisting equipment (PSL1 and PSL2), API Specification 8C. 3rd ed. Washington (DC): API;December 1998.L. Faqian et al. / Engineering Failure Analysis 14 (2007) 606613613Journal of Stored Products Research () Stored Grain Advisor Pro: Decision support system for insectmanagement in commercial grain elevators$P.W. Flinna,?, D.W. Hagstruma,1, C.R. Reedb, T.W. PhillipscaUSDA-ARS Grain Marketing and Production Research Center, Manhattan, KS, USAbDepartment of Grain Science and Industry, Kansas State University, KS, USAcDepartment of Entomology, Oklahoma State University, Stillwater, OK, USAAccepted 20 September 2006AbstractA decision support system, Stored Grain Advisor Pro (SGA Pro) was developed to provide insect pest management information forwheat stored at commercial elevators. The program uses a model to predict future risk based on current insect density, grain temperatureand moisture. A rule-based system was used to provide advice and recommendations to grain managers. The software was tested in aresearch program conducted at commercial grain elevators in Kansas and Oklahoma, USA. A vacuum-probe sampler was used to taketen 3-kg grain samples in the top 12m of each bin that contained wheat. After the insect species and numbers were determined for eachsample, the data were entered into SGA Pro. A risk analysis and treatment recommendation report for all bins was presented to the grainmanagers every 6 weeks. SGA Pro correctly predicted for 7180% of bins whether the grain was safe or at high risk of dense infestationand grain damage. SGA Pro failed to predict unsafe insect densities in only 2 out of 399 Kansas bins (0.5%) and in none of 114 bins inOklahoma. Grain managers who followed SGA Pros recommendations tended to fumigate only the bins with high insect densitiesinstead of fumigating all bins at their facility. This resulted in more efficient insect pest management because fumigating bins only wheninsect densities exceeded economic thresholds and treating only the bins that required fumigation minimized the risk of economic lossesfrom insects, reduced the cost of pest management, and reduced the use of grain fumigant.Published by Elsevier Ltd.Keywords: Rhyzopertha dominica; Cryptolestes ferrugineus; Decision support system; Model; Integrated pest management; Stored grain; Area-wide1. IntroductionMost cereal grain produced in the USA is stored incommercial facilities known locally as grain elevators.Major insect pests of stored wheat in the USA includeRhyzopertha dominica (F.), Sitophilus oryzae (L.), Crypto-lestes ferrugineus (Stephens), Tribolium castaneum (Herbst),and Oryzaephilus surinamensis (L.). The first two speciescause the most grain damage because the immature stagesdevelop inside the grain kernels. These internal feedinginsects are a major cause of insect contamination in wheatflour because the immature stages and pre-emergent adultscannot be completely removed from the wheat before it ismilled. Grain managers and regulators use the number ofinsect-damaged kernels (IDK) in wheat as an indirectmeasure of the density of internally-infested kernels. Ifmore than 32 IDK are found per 100g of wheat, the grainis classified as sample grade and unfit for humanconsumption (Hagstrum and Subramanyam, 2006). Atmost domestic flour mills, the wheat purchasing specifica-tions include a maximum IDK count of either 3 or 5/100g.Cryptolestes ferrugineus is a very common insect pest thatoften reaches high densities near the grain surface. Younglarvae of this species frequently feed on the germ of wholekernels and on fine material in the grain (Rilett, 1949).They leave the germ before becoming adults and do notcause IDK. Nevertheless, grain infested with this species islikely to receive a lower price than uninfested grain.ARTICLE IN PRESS/locate/jspr0022-474X/$-see front matter Published by Elsevier Ltd.doi:10.1016/j.jspr.2006.09.004$This paper reports the results of research only. Mention of aproprietary product or trade name does not constitute a recommendationor endorsement by the US Department of Agriculture.?Corresponding author. Tel.: +17857762707; fax: +17855375584.E-mail address: paul.flinn (P.W. Flinn).1Retired.Please cite this article as: Flinn, P., et al., Stored Grain Advisor Pro: Decision support system for insect management in commercial grain elevators.Journal of Stored Products Research (2007), doi:10.1016/j.jspr.2006.09.004Typically,controlofstored-graininsectsingrainelevatorsintheUSAincludesmonitoringofgraintemperature and calendar-based fumigations using phos-phine fumigant (Hagstrum et al., 1999). This approachoften fails to distinguish between bins with high and lowinsect densities and does not optimize the timing of thefumigation treatment. Therefore, grain may be unnecessa-rily fumigated, or the fumigation may not be timed toprevent high insect populations and grain damage fromoccurring. Although careful monitoring of grain tempera-ture often alerts the manager to potential mold and insectproblems (Reed, 2006), large populations of insects orsevere mold problems can develop before a temperatureincrease is noted.Incontrasttotraditionalinsectcontrolpracticescurrently used for most stored grain, the integrated pestmanagement (IPM) approach uses sampling to determine ifinsects have exceeded an economic threshold (Hagstrumand Flinn, 1992). Adapting IPM principles to insectcontrol in a grain elevator is complicated by the structureand operation of the facility. A large elevator may haveover 100 bins, and the bins may contain different types ofgrain, stored for different durations. The grain temperatureand moisture often vary greatly between bins, which affectsthe rate at which insects and molds grow and damage thegrain.To facilitate the development and implementation ofIPM practices in stored grain in the USA, the USDAsAgricultural Research Service recently funded a 5-yeardemonstration project for area-wide IPM for stored wheatin Kansas and Oklahoma (Flinn et al., 2003). This projectwas undertaken by a collaboration of researchers at theAgricultural Research Service (Manhattan, Kansas), Kan-sas State University (Manhattan, Kansas), and OklahomaState University (Stillwater, Oklahoma). We used twoelevator networks, one in each state, for a total of 28 grainelevators. One of the project goals was the development ofa decision support system for insect pest management forgrain stored in commercial elevators.Avalidatedinsectpopulationgrowthmodelwaspreviously developed for R. dominica in concrete elevatorstorage (Flinn et al., 2004). This model was used in adecision support system to make management recommen-dations based on current insect density, grain temperatureand grain moisture. A decision support system (StoredGrain Advisor) was developed previously for farm-storedgrain in the USA (Flinn and Hagstrum, 1990b). However,that software was not suitable for large commercialelevators because the grain sampling methods and recom-mendations were specific for farm-stored grain.Decision support systems for stored grain have beendeveloped in several countries. In Canada, CanStore, wasdeveloped to assist farmers in stored grain management(www.res2.agr.ca/winnipeg/storage/pages/cnstr_e.htm). InAustralia, Pestman ranks insect pest management recom-mendations by their cost and provides a graphical site planthat allow a manager to quickly find information aboutany bin (Longstaff, 1997). In the UK, Integrated GrainStorage Manager (Knight et al., 1999) is a new version ofGrain Pest Advisor (Wilkin and Mumford, 1994) that wasdeveloped with input from farmers and storekeepers tobetter suit their needs. Grain Management Expert System(Zonglin et al., 1999), was developed from Pestman for usein China. QualiGrain is an expert system for maintainingthe quality of stored malting barley (Ndiaye et al., 2003;Knight and Wilkin, 2004).None of the previously mentioned systems fit therequirements of the USA commercial grain storage system.We needed a management program that was based onintensive grain sampling for insect pests in each elevatorbin (at least ten 3-kg grain samples per bin to a depth of12m). In addition, the system needed to be able to predictinsect population growth for up to 3 months, based oncurrent insect density in the bin, grain temperature, andgrain moisture. In this paper, we describe the validation ofa decision support system that was developed as part of anarea-wide IPM demonstration project. The decision sup-port system uses current and predicted insect densityestimates to provide grain managers with an overall riskanalysis for the grain at their facility and recommendedtreatment options.2. Materials and methods2.1. Grain samplingAn area-wide IPM program for grain elevators wasstarted in 1998. Investigators collected data from twoelevator networks in south-central Kansas and centralOklahoma. Each network consisted of at least 10 ruralelevators and at least one terminal elevator. The ruralelevators typically receive grain from farmers and store itfor a shorter period of time compared to the terminalelevators, where most grain is received from rural elevators.Storage bins at these elevators were either upright concretebins, typically 69m in diameter and 3035m tall, or metalbins that are shorter and wider. Maize and other grainswere stored in the project elevators, but only the wheat wassampled during this project.Various sampling methods to estimate insect density inupright concrete grain bins were tested: probe traps placedat the grain surface, samples taken as the grain was movedon transport belts, and samples taken from grain dis-charged from the bins onto a stationary transport belt.Samples taken with a vacuum probe as the grain was at restin the storage bins provided the best estimate of insectdensity. Data collected with the vacuum probe were highlycorrelated with grain samples taken as the bin wasunloaded (r2 0.79, N 16, P 0.001). In addition,unlike the other sampling methods, the power probeallowed the grain to be sampled at any time, and itprovided a vertical profile of the insect distribution for eachbin. We used a Port-A-Probe (Grain Value Systems,Shawnee Mission, Kansas), which consists of a vacuumARTICLE IN PRESSP.W. Flinn et al. / Journal of Stored Products Research () 2Please cite this article as: Flinn, P., et al., Stored Grain Advisor Pro: Decision support system for insect management in commercial grain elevators.Journal of Stored Products Research (2007), doi:10.1016/j.jspr.2006.09.004pump powered by a 5.3KW gasoline engine connected byflexible plastic tubing to sections of rigid aluminum tubes1.2m long by 3.5cm wide. The probe was insertedvertically into the grain and a 3.9l (about 3kg) sample ofwheat was taken during every 1.2m transect of grain to adepth of 12m. In the concrete upright bins, the grain wassampled through the entry port. In metal bins, the probewas inserted at 35 locations across the surface. Grainsamples were extracted from the grain mass by suction andcollected in a cyclone funnel.Samples were processed twice over an inclined sieve(89?43cm, 1.6mm aperture) (Hagstrum, 1989) to sepa-rate insects from the wheat. Material that passed throughthe screen was collected on a pan below the screen, whichthen slid into a funnel at the bottom of the pan. A re-sealable plastic bag was attached to the funnel to collect thematerial that was separated from the grain sample. Ahopper above the screen held the grain sample and a funnelat the base of the screen directed material passing over thescreen into a plastic bucket. The sieve was inclined 241from horizontal and the opening of the hopper wasadjusted such that the sample passed over the screen inabout 25s. Each sample was passed over the sieve twotimes. Validation data for SGA Pro were selected from binsthat were sampled at least twice, starting in autumn, inwhich the wheat was not moved or fumigated. In a typicalbin (69m wide and 3035m tall), the sampling rate forvacuumprobesampleswas0.070.13kg/tofgrainsampled. In most cases, only the grain in the top 12m ofthe bin was sampled.2.2. Decision support softwareThe Stored Grain Advisor Pro (SGA Pro) softwarewas initially developed using Microsoft Access. Theprogramwasthenmodifiedandre-writtenusingVisual Basic 6.0. We designed a graphical user interfacethat provides a bin diagram for each elevator location(Fig.1).Datawereenteredusingthreedata-entryforms: insects, grain quality, and grain temperature. Dataentered in the insect form were: sample type (bottom,movingsample,probetrap,orvacuumsample)and the number of insects found in each sample for fiveprimary stored-grain insects (Cryptolestes spp., R. domin-ica, O. surinamensis, Sitophilus spp., and Tribolium spp.)(Fig. 2). Data entered for grain quality were: grade, %dockage,testweight,moisture,foreignmaterial,%shrunken or broken kernels, insect damaged kernels, %protein(Fig.3).Graintemperaturedatawerealsoentered into the database for each bin (data entry is similarto the grain quality form and is not shown here). Mostelevator bins were equipped with one or more cablescontaining up to 20 thermocouple-type sensors per cable.In bins not equipped with temperature sensors, investiga-tors inserted temporary probes to collect information ongrain temperature.The SGA Pro system will recommend either fumigation,aeration, or waiting untilthe next sampling periodbased on current insect density in the bin, grain tempera-ture, aeration capability, time of year, and predictedinsect density in 1, 2, and 3 months. For example,ARTICLE IN PRESSFig. 1. Elevator bin diagram from Stored Grain Advisor Pro; on the computer screen, bins of grain at high, moderate, and low risk for insect problems areshown in red, blue and green, respectively. In this figure, bin numbers that are light grey are at low risk, bins 615, 620 and 621 are at high risk, and the restare at moderate risk. Bin 620 is currently selected (using the mouse), and the information for this bin is shown in the bottom half of the screen.P.W. Flinn et al. / Journal of Stored Products Research () 3Please cite this article as: Flinn, P., et al., Stored Grain Advisor Pro: Decision support system for insect management in commercial grain elevators.Journal of Stored Products Research (2007), doi:10.1016/j.jspr.2006.09.004for bin 620 (Fig. 4), the program indicated that thecurrent insect density was 2.5kg-1and predicted a densityof 14.6insects/kg in 1 month. Twenty-eight percent of theinsects from the samples were species that caused IDK, soSGA Pro recommended fumigation followed by aeration tocool the grain.ARTICLE IN PRESSFig. 2. Insect data entry form for Stored Grain Advisor Pro. The number of insects for each 3-kg sample were entered into the form. For simplicity,common names are used for the insect species (flat Cryptolestes spp., lesser R. dominica, sawtooth O. surinamensis, weevil Sitophilus spp., flourbeetle Tribolium spp.).Fig. 3. Grain quality data entry form for Stored Grain Advisor Pro (grade grain grade, DKG(%) % dockage, TW test weight, moist(%) %grain moisture, DK(%) % damaged kernels, FM(%) % foreign material, SHBK(%) % shrunken or broken kernels, IDK number of insectdamaged kernels per 100g, protein(%) % protein).P.W. Flinn et al. / Journal of Stored Products Research () 4Please cite this article as: Flinn, P., et al., Stored Grain Advisor Pro: Decision support system for insect management in commercial grain elevators.Journal of Stored Products Research (2007), doi:10.1016/j.jspr.2006.09.004An equation was developed to predict insect populationgrowth based on current insect density, grain temperatureand moisture by running simulations for a model of R.dominica (Flinn and Hagstrum, 1990a), over temperaturesfrom 21.5 to 33.51C and moistures from 9.5 to 13.5%.Tablecurve 3D version 3 (SPSS, 1997) was used to fit anequation to the model-generated data, where Z is the rateof increase over 30 days, X is temperature, and Y ismoisture:Z 9:2004 ? 1:6898X 0:07872? 0:0011X2 0:1841Y=1 ? 0:0197X ? 0:0161Y.1:0This equation fitted the data well (R2 0.98, N 25).Because we needed to predict only 13 months ahead, thisequation was adequate for quickly estimating futurepopulations for many bins present in the database (oftenmore than 100). Although C. ferrugineus was often themost numerous species during the first month of storage,we based Eq. (1.0) on R. dominica because it is the moredamaging species, it was more common than C. ferrugineuslater in the season, and the predicted rates of increase forboth species were fairly similar (Hagstrum and Flinn,1990). We did not use a model for S. oryzae because thisspecies was found in about 1% of the wheat samples,whereas, R. dominica was found in approximately 60% ofthe samples.SGA Pro used a rule-based algorithm to determinewhether bins were safe, moderate, or at high risk of havinginsect densities that exceed certain thresholds, based on thecurrent and predicted insect density, grain temperature,and grain moisture. Insect economic thresholds can beadjusted by the user (Fig. 5). In addition, alerts can also beset for: high grain moisture, high thermocouple readings,and high numbers of internally feeding insects in anindividual sample.SGA Pro was tested during the final 2 years of the area-wide IPM study. Bins at each elevator were sampled atapproximately 6-week intervals, data were entered intoSGA Pro, and the report recommendations were shown totheelevatormanagers.SGAProwasvalidatedbycomparing predicted insect densities and control recom-mendations with actual insect densities in the same bins 6weeks later. Validation data came from bins in which thegrain had not been turned or fumigated for at least twosampling periods.3. ResultsIn the Kansas data set from 2002, SGA Pro correctlypredicted that bins were safe or at high risk in 285out of 399 cases (Table 1). Forty-seven of the 399 binsrequired fumigation. SGA Pro failed to predict unsafeinsect densities in only two bins (0.5%), and the insects inthese isolated instances were mostly near the surface,suggestingrecentimmigration.Thesimplegrowthmodel used by SGA Pro tended to overestimate insectdensities in bins that were at medium risk (112 out of 399bins). All of the bins that the software predicted to be athigh risk contained insect densities greater than thethreshold at the next sampling period. In Oklahoma,SGA Pro correctly predicted bins that were safe or athigh risk in 107 out of 133 total bins. Forty-five of the133 bins needed to be fumigated. All of the bins that theprogram determined as being safe turned out to haveinsect densities below the threshold of 2insects/kg 6 weekslater. As in Kansas, SGA Pro tended to overestimateinsect densities in bins that were at medium risk (26 out of131 bins).ARTICLE IN PRESSFig. 4. Stored Grain Advisor recommendation report. The report shows alerts for five elevator bins (Current average insects per kg grain, 1Mon predicted insect density in 1 month, 2 Mon predicted insect density in 2 months, IDK insect % of the insects in the sample that cause IDK,Max SS internal highest number of internal insects in any single sample, and management option recommended actions for the elevator manager).P.W. Flinn et al. / Journal of Stored Products Research () 5Please cite this article as: Flinn, P., et al., Stored Grain Advisor Pro: Decision support system for insect management in commercial grain elevators.Journal of Stored Products Research (2007), doi:10.1016/j.jspr.2006.09.0044. DiscussionCompared to other decision support systems for largecommercial grain stores, SGA Pro is the first that usesintensive sampling of the grain to determine if insectdensities exceed economic thresholds. In countries wherethis type of software has been developed, for example UK,Australia, and Canada, the grain trade operates on a zerotolerance for insects in stored grain. This makes it difficultto implement economic thresholds for insect pests. SGAPro is also the first decision support system for commercialgrain storage that has been field validated, certainly to theextent presented here. Integrated Grain Storage Manager(Knight et al., 1999) was revised with input from storekeepers(atypeofvalidation),andGrainStorageInformation System (Mann et al., 1997) was verified byseveral experts.We demonstrated that the use of SGA Pro resulted in alow type A error (SGA Pro predictso2insects/kg, andactual density in 6 weeks is42insects/kg of wheat),but a rather moderate type B error (SGA Pro predicts410insects/kg, and actual density in 6 weeks is o10in-sects/kg). A low type A error and moderate type B errortranslates in practice to a low probability of graindeterioration.Althoughunnecessaryexpenditureongrain fumigation occurs from time to time, the cost ofsuch errors is minimal. Experience with companies thatadopt a data-based decision model has shown that theARTICLE IN PRESSFig. 5. Economic thresholds used by Stored Grain Advisor Pro are adjustable by the user. In addition to settings thresholds for average and single sampleinsect counts, alerts can also be set for temperature hotspots or high-moisture grain samples.Table 1Number of correct predictions by Stored Grain Advisor Pro, and type Aand B errors for elevator bins in Kansas and OklahomaLocationTotalCorrectType AaType BbNN%N%N%Kansas39928571.420.511228.1Oklahoma13310780.500.02619.5aType A errors: software predicts safe (o 2insects/kg) and actualdensity in 6 weeks was 42 insects/kg of wheat.bType B errors: software predicts medium risk (410insects/kg) andactual density in 6 weeks was less than 10insects/kg of wheat.P.W. Flinn et al. / Journal of Stored Products Research () 6Please cite this article as: Flinn, P., et al., Stored Grain Advisor Pro: Decision support system for insect management in commercial grain elevators.Journal of Stored Products Research (2007), doi:10.1016/j.jspr.2006.09.004unnecessary grain turning may have a hidden benefit.Grain managers, because they are conditioned to turn andfumigate wheat at a certain time of year, seem to feel moresecure using the new approach if it recommends someinsurance grain turning. They are therefore more likelyto adopt the new approach compared to a program thatrecommends little or no turning and fumigation for longperiods of time.SGAProprovidesacomparisonofthecostoffumigating grain in all bins vs. sampling in all bins andfumigating only grain with high insect densities (Fig. 6).For example, fumigating all 33 bins at an elevator storing17,600tonnes (646,698 bushels) of wheat could cost $5220USD (electrical costs for turning per bushel $0.0033USD, phosphine fumigant $0.002 per bushel, loss inwheat volume $0.0028 per bushel). However, if theelevator manager knows that only eight of these bins havehigh insect densities, fumigating only these eight bins plusthe cost of sampling ($0.00205 USD per bushel) all 33 binsis $3,053 USD for a savings of $2,167 USD.SGA Pro software is freely available to the public at theGrain Marketing and Production Research Center web site(/npa/gmprc/bru/sga). Learning to usethe software is fairly easy; however, using the samplingequipment and identifying the insects does require sometraining.A private company is using SGA Pro with the samplingmethods developed in this project, and has providedscouting services to more than 70 elevators in Kansas,Oklahoma,andNebraska.Industryresponsetotheavailability of grain scouting services for IPM in storedgrain appears to parallel that of farmers initial responsesto crop consultants that first offered IPM services forproduction agriculture. Most grain managers resist thechange to data-based decision making. A few earlyadopters of grain scouting, those who appeared to be opento the increased use of computer technology in grainmanagement, have embraced the entire information-baseddecision-makingconcept.Severalmanagersperceivedvalue in parts or components of the services offered bythe grain scouting company. For example, several of thecompanys clientele initially purchased only the servicesthat had obvious benefits to the grain merchandiser, suchas the wheat protein data generated by vacuum probesampling. Over time, these users began to perceive thepotential benefits of the insect scouting service.To quantify the effect of the information-based ap-proach to insect pest management, the incidence anddensityofinsect-damagedwheatkernelsinsamplescollected in the autumn of 2003, the first year of thescouting companys operation, were compared with sam-ples collected during the same time period 1 year later.ARTICLE IN PRESSFig. 6. Economic analysis calculated by Stored Grain Advisor Pro. Users can change costs for electricity, fumigant, wheat price, shrink factor (height ofgrain lost by turning and fumigating grain), and sampling.P.W. Flinn et al. / Journal of Stored Products Research () 7Please cite this article as: Flinn, P., et al., Stored Grain Advisor Pro: Decision support system for insect management in commercial grain elevators.Journal of Stored Products Research (2007), doi:10.1016/j.jspr.2006.09.004Data from four elevators were used in this analysis,providing 2132 data points. The frequency of samples witha high density (410/100g) of kernel damage was reducedby 24% (chi square 34.8, Pp0.01), and the mean densityof kernel damage (2.5/100g vs. 1.9/100g) was significantlydifferent (Pp0.05).A case study that illustrates the value of the IPMapproach used by SGA Pro was created accidentally whena scouting report was not relayed to a grain manager.Twenty-four bins of wheat were scouted at an elevator thatwas manned only part of the year. The manager was awayduring the scouting and was unaware of the scoutingreport. When the manager returned, he began treating thegrain based on his traditional approach. When the scoutingcompanys crew returned 6 weeks later to conduct routinere-sampling, seven bins had been turned and fumigated.Based on vacuum probe sampling, the tradition-baseddecisions were correct in three of the seven bins; that is,thegrainthatwasfumigateddid,infact,requirefumigation. In two cases, grain containing too few insectsto warrant fumigation was treated. For two of thefumigated bins, the data were inconclusive regarding thevalidity of the traditional approach. Of the 17 bins that hadnot been fumigated, the previous scouting report hadrecommended no action until further sampling in 10bins. In three of these bins, insect densities had increased inthe intervening period such that fumigation was warrantedand would be more effective than if it had been doneprematurely, but no significant grain damage occurred. Inall grain for which SGA Pro recommended no action, nograin damage had occurred in 6 weeks. In the remainder (7)of the 17 untreated bins, the previous report by SGA Prohad recommended immediate fumigation. In six of seven,the second sampling showed insect populations exceedingacceptable levels, and grain damage had occurred becausefumigation had not been done when recommended. In onebin, insect numbers had not increased significantly and nosignificant grain damage had occurred. The results of thiscase study closely parallel those of the analysis describedabove from data taken during the research project. That is,SGA Pro recommended immediate action in all caseswhere it was needed but slightly over-estimated the numberof grain lots requiring fumigation in 6 weeks.Investigators recognized that area-wide IPM will beadopted by grain elevator managers only if it is moreeffective and profitable than the traditional approach, andif it fits into their current marketing and grain managementpractices. We tried to determine how elevator managersmight use insect-monitoring information to manage insectproblems in their grain bins. The findings of the area-wideIPMprojecthavebeencommunicatedtomanagersthrough nine newsletters, at training programs in Kansas,Oklahoma, Nebraska, and Minnesota, and at two recentInternationalGrainElevatorandProcessingSociety(GEAPS) annual meetings. Information gathered in thisstudy was used to develop extension publications forstored-grain integrated pest management.The sampling routines and decision support softwarethat we developed have several advantages over calendar-based fumigation. Treating bins only when insect densitiesexceed economic thresholds and treating only the bins thatneed to be treated minimizes the risk of economic lossesfrom unexpected insect problems, reduces the cost of pestmanagement, and reduces the use of fumigant. Minimizingthe use of fumigant improves worker safety by reducingexposure to phosphine, and reduces the probability thatinsect populations will develop resistance to phosphine.AcknowledgmentsWe thank Paul Fields (Agriculture and Agri-FoodCanada, Winnipeg, Canada), and Mark Casada (USDA-ARS, Grain Marketing and Production Research Center)for reviewing an early version of the manuscript. Specialthanks to Ken Friesen and Kui Zhang for programmingSGA Pro, and to Skip Allen, Sherry Craycraft and GaryGilbert for providing suggestions for software improve-ment and for managing the grain sampling teams. We alsothank the elevator managers who provided access andassistance. This research was funded by an Area-Wide IPMprogram grant from the United States Dep
- 温馨提示:
1: 本站所有资源如无特殊说明，都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等，如果需要附件，请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸，网页内容里面会有图纸预览，若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对用户上传分享的文档内容本身不做任何修改或编辑，并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容，请与我们联系，我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
人人文库网所有资源均是用户自行上传分享，仅供网友学习交流，未经上传用户书面授权，请勿作他用。
川公网安备: 51019002004831号