简介：Effectsofnon-ionicpolyacrylamide(PAM),anionicpolyacrylamide(PHP),cationicpolyacrylamide(PCAM),non-ionicpolyvinylalcohol(PVA),anionichydrolyzedpolyacrylonitrile(HPAN)andpolyethleneoxide(PEO)onthephysicalpropertiesofthreedifferentsoilstpeswerestudied.contentofwater-stableaggregateslargerthan0.25mmincreasedtovaryingextentsfordifferentsoilsandsoilconditioners,Amongthesixkindsofcondiftioners,non-ionicpolyacrylamide(PAM)wasthemosteffectiveforredsoilwhilepolyethyleneoxide(PEO)theleasteffectiveforChaosoil,redsoilandyellow-brownsoil.Water-stableaggregateswiththemolecularweightofPEOwithinacertainrange.OnlyevaporationrateofChaosoildecreasedafteraplicationofPAMandHPANtoChaosoilandredsoil.

简介：Withtheincreaseoftheutilizationofbamboo,wemustfindoutmoreinbambooproperties.AccordingtothenationalstandardGB/T15780-1995,thispaperanalyzedtheair-drieddensityandmechanicalpropertiesofMosobambooindifferentagesandstalkparts.Theresultsshowedthatboththeageandthestalkparthaveremarkableeffectsonair-drieddensityandmechanicalproperties.Theeffectofageismuchmoreprominentthanthatofstalkpart.Theperformanceshows:upper>middle>down,whichincr...

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简介：Theobjectiveofthisstudywastoinvestigatethephysicalandmechanicalperformanceofflakeboardreinforcedwithbamboostrips.Thestudyinvestigatedthreedifferentbamboostripalignmentpatternsandanexperimentalcontrol.Allpanelsweretestedinstaticbendingbothalongparallelandperpendiculartothelengthsofthebamboostrips.Internalbondstrength(IB),thicknessswelling(TS),linearexpansion(LE),andwaterabsorption(WA)werealsoexamined.Asexpected,modulusofrupture(MOR)andmodulusofelasticity(MOE)weresubstantiallygreaterforallthreeexperimentalpaneltypesascomparedtothecontrolgroup.LEwasalsoimprovedforallthreeexperimentalpanelgroups.ThebamboostripalignmentpatternshadnosignificanteffectonTS,WAandIB.ThesamplemeansforMOR,MOEandLEtestedperpendiculartothebamboostriplengthsyieldedslightlylowermeanvaluesthancorrespondingsamplestestedparalleltothebamboostripslengths.Thisdifferenceinmechanicalpropertiesislargelyattributedtolowpaneldensityinthefailurezones.

简介：Inthispaper,thephysicalandmechanicalpropertiesoflaminatedbamboolamberwerestudiedbytestingmoisturecontent,delaminationratio,horizontalshearstrength,MOEandMORofthestructure-usematerial,inthesametime,thesesubjectsoffinger-jointweretestedtoo.Theresultsshowedthat,thehorizontalshearstrength,MOR,MOEoflaminatedbambooweresuperiortotheordinarystructure-usetimberinarchitecture,suchasPinus.Theperformanceofagingtestwasnotextraordinary,althoughthephysicalandmechanicalpropertiesoflaminatedbamboolamberdecreasedafteragingtest,thesepropertieswerebeyondPinusyet.

简介：Thisarticle,bycomparingthebasicconceptsofsubstrateandsoil,theircompositionofsubstanceandmethodsofmeasuringtheindexesofphysicalandchemicalproperties,analyzesandresearcheswaysofchoosingsubstrateforcultivationwithfacilities.Itindicatesthatthenormalphysicalandchemicalindexesofevaluatingasubstratearebulkdensity,totalporosity,non-capillaryporosity,ratioofbigporositytosmallporosity,thepHandtheelectricalconductivity(EC)valueofthesubstrate.By...

简介：TocomparethedevelopmentofphysicalcrustsinthreetypicalcultivatedsoilsofChina,ablacksoil(LuvicPhaeozem),aloesssoil(HaplicLuvisol),andapurplesoil(CalcaricRegosol)werepackedinsplashplateswithcoveredanduncoveredtreatments,andexposedtosimulatedrainfall.Meshescoveredabovethesurfacesofhalfofsoilsamplestosimulatetheeffectsofcropresidueoncrusting.Theresultsindicatedaprogressivebreakdownofaggregatesonthesoilsurfaceasrainfallcontinued.Thebulkdensityandshearstrengthonthesurfaceofthethreesoiltypesincreasedlogarithmicallyasrainfalldurationincreased.Duringthefirst30minofsimulatedrainfall,thepurplesoildevelopeda7-8mmthickcrustandtheloesssoildevelopeda3-4mmthickcrust.Theblacksoildevelopedadistinguishable,butstillunstable,crustafter80minofsimulatedrainfall.Soilorganicmatter(SOM)content,themeanweightdiameter(MWD)ofsoilaggregates,andsoilclaycontentwerenegativelycorrelatedwiththerateofcrustformation,whereasthepercentageofaggregatedispersion(PAD),theexchangeablesodiumpercentage(ESP),andthesiltandsandcontentswerepositivelycorrelatedwithcrusting.Mechanicalbreakdowncausedbyraindropimpactwastheprimarymechanismofcrustformationintheblacksoilwithmorestableaggregates(MWD25.0mm,PAD3.1%)andhigherSOMcontent(42.6gkg~(-1)).Slakingandmechanicaleluviationweretheprimarymechanismsofcrustformationinthepurplesoilwithlowclaycontent(103gkg~(-1)),cationexchangecapacity(CEC,228mmolkg~(-1)),ESP(0.60%),andSOM(17.2gkg~(-1)).MechanicalbreakdownandslakingwerethemostimportantintheloesssoilwithlowCEC(80.6mmolkg~(-1)),ESP(1.29%),SOM(9.82gkg~(-1)),andhighPAD(71.7%)andMWD(4.6mm).Simulatedresiduecoverreducedcrustformationinblackandloesssoils,butincreasedcrustformationinpurplesoil.

简介：Inordertobetterunderstandthereasonswhyeucalyptveneercheckseasilyandseverely,woodsamplesofthreeeucalyptspecieswereselected,andtheiranatomicalandphysicalpropertieswereexaminedaccordingtoconventionalmethodsandthenationalstandards.Theeffectsofvariancesincellwallthicknessofwoodfibreandvessel,anddiameterofthecelllumenaswellasthetissueratioonthequalityofplywoodveneerwereanalysed.Theresultsshowthat:1)ThereisagreatdifferenceinfibrecellwallthicknessanddiameterofthecelllumenbetweenearlywoodandlatewoodofEucalyptusdelegatensis.2)E.obliquahasahighwoodfibretissueratioandthethickestfibrecellwall,butthedifferenceinthefibrecellwallthicknessbetweenearlywoodandlatewoodisthesmallest.3)ThewoodfibretissueratioofE.regnansissmallerthanthatofE.obliqua,anditswoodfibrecellwallisthethinnestandthereisonlyaverysmalldifferenceinfibrecellwallthicknessbetweenearlywoodandlatewood.Thedifferenceinthediameterofwoodfibrecelllumenamongearlywood,transitionareaandlatewoodisalsosmall.4)E.delegatensishasthehighesttangentialshrinkagerateandradial-tangentialshrinkagerate,andE.obliquahasthelowest.Itisthevariabilityofwoodanatomicalpropertiesofthesespeciesthatcausethedifferenceintheveneershrinkage,andthenaffectsplywoodveneerquality.

简介：Determiningthephysicalandmechanicalpropertiesofsoilanditsbehaviorforengineeringprojectsisessentialforroadconstructionoperations.Oneofthemostimportantprinciplesinforestroadconstruction,whichisusuallyneglected,istoavoidmixingorganicmatterwithroadmaterialsduringexcavationandembankmentconstruction.Thecurrentstudyaimedtoassesstheinfluenceoforganicmatteronthephysicalpropertiesandmechanicalbehaviorsofforestsoilandtoanalyzetherelationbetweentheamountoforganicmatterandthebehaviorofforestsoilasroadmaterial.Atypicalsoilsamplefromthestudyareawascollectedbesideanewlyconstructedroadbed.Thesoilwasmixedwithdifferentpercentagesoforganicmatter(controltreatment,5,10,and15%bymass)anddifferenttestsincludingAtterberglimits,standardcompaction,andCaliforniabearingratio(CBR)testswereconductedonthesedifferentsoilmixtures.Theresultsshowedthatsoilplasticityincreasedlinearlywithincreasingorganicmatter.Increasingtheorganicmatterfrom0%(control)to15%resultedinanincreaseof11.64%oftheplasticlimitand15.22%oftheliquidlimitafterdryingat110℃.Also,increasingtheorganicmattercontentreducedthesoilmaximumdrydensityandincreasedtheoptimummoisturecontent.Increasingtheorganicmatterfrom0to15%resultedinanincreaseof11.0%oftheoptimummoisturecontentandadecreaseof0.29g/cm3ofthemaximumdrydensity.OrganicmatterdecreasedtheCBR,whichisusedastheindexofroadstrength.Adding15%organicmattertothesoilresultedinadecreaseoftheCBRfrom15.72to4.75%.Therewasasignificantdifferencebetweenthetwodryingtemperatures(60and110℃)forthesameorganicmattermixtureswithlowerwatercontentvaluesafterdryingat60℃.Theresultsrevealedtheadverseinfluenceoforganicmatteronsoilengineeringpropertiesandshowedtheimportanceoforganicmatterremovalbeforeexcavationandfillconstruction.

简介：Twokindsofbigsympodialbamboo,D.YunnanicusHsuehandWhangee(D.MembranaceusMunro)andtheirphysicalandmechanicalpropertieshavebeenstudiedinthepaper.TheresultsshowedthatthewhangeehasbetterphysicalpropertiesthanthatoftheYunnanicus,suchashigherdensity,lowertangentialandlongitudinaldryshrinkages.ThatalsoshowedthatWhangeehasstrongermechanicalpropertiesinMORandMOE,compressivestrengthandshearstrengthparalleltothegrain.Comparedwithsomewoodspeciesusedinarchitecture,thephysicalandmechanicalpropertiesofthetwokindshavereachedtherequirementofsomewoodarchitecturestructurematerials.

简介：Theeffectsoflay-uplayernumbersonlaminatedbamboobundleboard’sphysicalandmechanicalpropertiesandconnectionperformancewereanalyzed.Theresultsshowthatundertheconditionsofsamelayernumbers,alongwiththeincreaseofthelay-updirections,thebendingstrength,bendingmodulus,compressionstrengthandhorizontalshearstrengthofthelaminatedboardshowedadownwardtrend,whileusingnon-singledirectionlay-upstructure,theboard’swaterproofpropertywaslowerthanthatofsinglelay-upboard,buttheboard’sconnectionperformancewasraised.Therefore,intherealapplication,withtheconditionofguaranteeingthemechanicalpropertiesoftheboardtomeetoperatingrequirements,thelay-updirectionsshouldbeincreasedtoimprovetheboard’sconnectionperformanceandtoincreasetheboard’ssafety.

简介：Assessmentofsoilqualityisimportantforoptimumproductionandnaturalresourcesconservation.AgriculturalandpasturesoilqualitiesofDeh-SorkhregionlocatedatsouthofMashhad,northeasternIranwereassessedusingtheintegratedqualityindex(IQI)andNemeroqualityindex(NQI)modelsincombinationwithtwodatasets,i.e.,totaldataset(TDS)andminimumdataset(MDS).Inthisstudy6soilpropertiesconsideredasMDSwereselectedoutof18propertiesasTDSusingprinciplecomponentanalysis.Soilsamplesweredividedinto3groupsbasedonoptimumrangesof8soilphysicalqualityindicators.Soilsampleswiththemostindicatorsatoptimumrangewereselectedasgroup1andthesampleshavingfewerindicatorsatoptimumrangewerelocatedingroups2and3.Optimumrangesofsoilporesizedistributionfunctionswerealsodeterminedassoilphysicalqualityindicesbasedon8soilphysicalqualityindicators.Poresizedistributioncurvesofgroup1wereconsideredastheoptimumporesizefunctions.Theresultsshowedthatrelativelyhighorganiccarboncontentscouldimproveporesizedistribution.Meancomparisonsofsoilphysicalqualityindicatorsdemonstratedthatmeanweightdiameterofwetaggregates,structuralstabilityindex,theslopeofmoistureretentioncurveatinflectionpoint,andplantavailablewatercontentinagriculturallandusedecreasedsignificantlyinrelationtopasturelanduse.Inaddition,theresultsdemonstratedthatthestudiedMDScouldbeasuitablerepresentativeofTDS.78%ofpasturesoilshadtheoptimumporesizedistributionfunctions,whilethisparameterforagriculturalsoilswasonly13%.Ingeneral,thesoilsofthestudiedregionshowedhighlimitationsforplantgrowthaccordingtothestudiedindicators.

简介：ThestudywasconductedtoevaluateeffectofratiooffacetocoreparticlesonmechanicalandphysicalpropertiesoforientedstrandboardproducedfromEthiopianhighlandbamboo.Three-layeredorientedparticleboardsweremanufacturedwith4proportionsoffacetocoreparticlesat750kg/m~3targetdensity.Tenpercentureaformaldehyderesinwasusedasabinder.StrengthanddimensionalstabilityperformancesofallboardswereassessedbasedonISOstandards.Theresultsshowedthatmodulusofrupture...

简介：火影响物理、化学的性质和土壤自然生态系统的生物活动。这研究在唐米燕区域被进行，在西方的伊朗的Ilam省。学习地点是110公顷，在我们在被火严厉分类的区域取样了土壤的地方：低(LS)，高度(HS)和中等严厉(MS)，并且未燃(UB)，它用作控制。在每个严厉班上，25个横断点随机为测量被选择。在每个横断阴谋中心附近，3件土壤样品随机被选择，土壤收集了从0～20?厘米深度被合为在实验室分析被使用在那个点代表条件的一件合成样品。在UB和LS火类上的阴谋有类似的土壤条件并且有象浸透的潮湿，器官的碳，二氧化碳，和淤泥和泥土内容那样的因素的更高的值。相反，在HS和MS火严厉班上的阴谋沿着在土壤酸味，电的传导性，阳离子交换能力，可存取的磷，可存取的钾，体积密度，和沙代表了坡度的第一轴在积极方向被聚类。土壤属性在HS和MS火严厉班的区域是类似的，而在LS班和UB控制上的土壤条件是很类似的。在LS区域任何一个的火显著地没改变物理化学药品的土壤性质和微生物引起的基础呼吸，否则土壤能在被烧以后快速恢复。

简介：作为常规授精的一种选择评估器官的修正案的使用，沃土土壤的一个10年的实验在在Guadalquivir河山谷与化肥(NPK)和植物的堆肥(器官的化肥)使用的温室和室外的阴谋在一个庄稼旋转系统下面被进行，西班牙。土壤上的这二不同授精政体的效果物理性质被评估。玷污器官的碳(OC)，土壤体积密度(BD)，土壤水保留(WR)，可得到的水内容(AWC)，总数稳定性(作为)，并且玷污物理质量(德克斯特的索引，S)被决定。器官的化肥的使用增加了OC并且导致了的重要增加作为并且在与在温室和室外的阴谋的矿物质化肥申请相比的BD的减少。而温室阴谋出现了，室外的阴谋显示出最低BD价值象价值最高。在10年的实验的最后年里，S参数在器官的化肥阴谋是显著地更高的，特别为温室阴谋。在学习经期的结束，在在在在两个系统的治疗之间的领域能力(FC)的WR没有重要差别；AWC在矿物质在温室阴谋，但是更高也是类似的室外的阴谋。在矿物质化肥处理，在物理性质的小改进也与以前的集中的收割系统相比由于不太好攻击的耕种的利用被观察。物理土壤性质与土壤OC被相关。持续管理技术象器官的修正案的使用那样并且低或没有耕种改进了土壤物理性质，尽管有在管理的差别，那显著地逻辑地影响了结果。

简介：Soilqualityassessmenthasbeensuggestedasaneffectivetoolforevaluatingsustainabilityofsoilandcropmanagementpractices.Theobjectiveofthisstudywastodevelopasensitivesoilqualityindex(SQI)basedonbulkdensity(BD),water-holdingcapacity(WHC),water-stableaggregates(WSA),aggregatemeanweightdiameter(AMWD),totalorganicC(TOC)andCinputtoevaluatetheimportantrice-wheatcroppingsystemonanInceptisolinIndia.Along-termexperimenthasbeenconductedfor18yearsattheIndianCouncilofAgriculturalResearch-IndianInstituteofFarmingSystemsResearch,Modipuram,India.Thetreatmentsselectedforthisstudywerecomprisedofano-fertilizercontrolandN,PandKfertilizers(NPK)combinedwithZnandSfertilizers(NPK+Zn+S),farmyardmanure(NPK+FYM),greengramresidues(NPK+GR)andcerealresidues(NPK+CR),laidoutinarandomizedcompleteblockdesignwiththreereplications.SoilsampleswerecollectedandanalyzedforBD,WHC,WSAandTOC.Correlationanalysisrevealedthatbothriceandwheatyieldssigni?cantlyincreasedwiththeincreasesinAMWD,TOCandCinput,butdecreasedwiththeincreaseinBD.TheSQIvalueswerethengeneratedbasedonregressionanalysisofBD,WSA,AMWD,TOCandCinputwithriceandwheatyieldsforthe0–15and15–30cmsoillayers,respectively.RegressionanalysesbetweencropyieldsandSQIvaluesshowedaquadratictypeofrelationwiththecoeffcientofdetermination(R~2)varyingfrom0.78to0.89.Withregardtosoilsustainability,applyingcropresiduestobothriceandwheatcouldmaintainsoilqualityforalongerperiod,whereasthehighestyieldsofboththecropswererecordedintheNPK+Zn+Streatment.Theregressionequationsdevelopedinthisstudycouldbeusedtomonitorsoilqualityinasubhumidtropicalrice-wheatcroppingsystem.

简介：TheFabaceae(legumefamily)isoneofthelargestfamiliesofplantswithaworldwidedistributionandamajorroleinagricultureandinagroforestry.Ahardseedcoatimpermeabletowaterisatypicalfeatureofseveralspecies.Physicaldormancydelaysandreducesgerminationsothatmechanical,physicalandchemicalscarificationmethodshavebeenclassicallyusedtobreakseeddormancyofmanyspecies.WeevaluatetheeffectivenessofamethodologytoscarifyseedsofseveralwoodyFabaceaeofecologicalandeconomicalimportance,includingRobiniapseudoacaciaandAcaciadealbataandtheshrubsCytisusscoparius,C.multiflorusandUlexeuropaeus.Wedescribetheoptimizeduseofahandheldrotarytool(HRT),andcompareitseffectivenesswithotherscarificationmethodsreportedtobreakdormancysuchasboilingordryheating.Totalgerminationand/orspeedofgerminationwereenhancedaftertheapplicationoftheHRT,withgerminationpercentagessignificantlyhigherthanthoseachievedbyothermethodsofscarification.Basedonathoroughliteraturereview,amodeofactionfortheHRTissuggestedwhichcouldoperatebybreakingthephysicalandphysiologicaldormancyoftreatedseedsthroughthecombinedactionofcoatabrasionandmoderatetemperatures.Consideringtheseresults,werecommendtheapplicationofthisrapid,effective,low-costandhighlyreproducibleHRTmethodtobreakseeddormancyandenhancegerminationofthesespeciesandotherswithsimilardormancyconstraints.