检索结果-南通市图书馆

Influence o. Degree o. Co.d-Drawing o. the Mechanical Pro.erties o. Lo. Carbo. Steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Materials Sciences and Applicatio.s 2011年第11期2卷 1556-1563页

作者： Nurudeen A. Raji oluleke o. oluwole 不详

Lo. carbo. steel metal is used fo. the manufacture o. nails. Steel wire with <0.3% C co.tent is co.d-drawn thro.gh a series o. drawing dies to.reduce the diameter o. the wire to.the required diameter o. the nails. A 0... 详细信息

Lo. carbo. steel metal is used fo. the manufacture o. nails. Steel wire with o.tent is co.d-drawn thro.gh a series o. drawing dies to.reduce the diameter o. the wire to.the required diameter o. the nails. A 0.12%w C steel wire co.d drawn pro.ressively by 20%, 25%, 40% and 50% was investigated. The influence o. the degree o. co.d drawing o. the mechanical pro.erties o. the carbo. steel material were studied using the tensile test, impact test and hardness test experiments in o.der to.replicate the service co.ditio. o. the nails. The tensile test was do.e o. a Mo.tanso. tenso.eter to.investigate the yield strength and the tensile strength o. the material as the degree o. defo.matio. increases. An Izo. test was used to.determine the impact to.ghness o. the steel using the Ho.nsfield impact machine and the hardness numbers were o.tained fo. the different degrees o. drawn defo.matio. o. the steel o. the Brinnel tester. The study used the stress-strain relatio.ship o. the tensile test experiment to.study the effect o. the degree o. co.d-drawing defo.matio. o. the yield strength and tensile strength pro.erties o. the lo. carbo. steel. The yield strength o. the material was o.served to.reduce with increasing degree o. co.d-drawing, an indicatio. o. reductio. in the ductility and the tensile strength o. the material reduced with increasing degree o. co.d-drawn defo.matio.. The ability o. the material to.resist impact lo.ds when nails are hammered reduced with increasing degree o. drawn defo.matio. as a result o. strain hardening o. the material after the drawing o.eratio.. Ho.ever the resilience o. the material to.further co.d drawn defo.matio. increased with increasing degree o. defo.matio. as evident in the Brinnel hardness number which increases with the degree o. drawing defo.matio.. This is an indicatio. o. the material’s appro.ch to.brittleness as the degree o. drawn defo.matio. increases.

关键词： Co.d-Drawn Defo.matio. Stress-Strain To.ghness Yield Strength Tensile Strength

o.timizatio. o. the Annealing Parameters fo. Impro.ed Tensile Pro.erties in Co.d Drawn 0.12 wt% C Steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Engineering（科研） 2013年第11期5卷 870-876页

作者： Nurudeen A. Raji oluleke o. oluwole Mechanical Engineering Department University of Ibadan Ibadan Nigeria

Drawn lo. carbo. steel is characterized by brittle fracture. These defects are asso.iated with the po.r ductility and high strain hardening due to.the co.d wo.k. There is a need therefo.e to.determine o.timum heat treatment parameters that co.ld ensure impro.ed to.ghness and ductility. Determining the o.timum annealing parameters ensures valued recrystallizatio. and also.minimizes grain gro.th that co.ld be detrimental to.the resulting pro.uct. 40% and 55% co.d drawn steels were annealed at temperatures 500℃ to.650℃ at intervals o. 50℃ and so.ked fo. 10 to.60 minutes at interval o. 10 minutes to.identify the temperature range and so.king time where o.timum co.binatio. o. pro.erties co.ld be o.tained. Tensile test and impact to.ghness experiments were do.e to.determine the required pro.erties o. the steel. Po.yno.ial regressio. analysis was used to.fit the pro.erties relatio.ship with so.king time and temperatures and the classical o.timizatio. technique was used to.determine the minimum so.king time and temperature required fo. impro.ed pro.erties o. the steel. Annealing treatment at 588℃ fo. 11 minutes at grain size o. 44.7 mm can be co.sidered to.be the o.timum annealing treatment fo. the 40% co.d drawn 0.12 wt% C steel and 539℃ fo. 17 minutes at grain size o. 19.5 mm fo. the 55% co.d drawn 0.12 wt% C steel.

关键词： Annealing Steel Co.d Drawn So.king Time Strength o.timizatio.

Recrystallizatio. Kinetics and Micro.tructure Evo.utio. o. Annealed Co.d-Drawn Lo.-Carbo. Steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Jo.rnal o. Crystallizatio. Pro.ess and Techno.o.y 2013年第4期3卷 163-169页

作者： Nurudeen A. Raji oluleke o. oluwole Department o. Mechanical Engineering University of Ibadan Ibadan Nigeria

The recrystallizatio. behavio. o. co.d-drawn 0.12 wt% C steel during annealing at temperatures 600°C and 650°C was investigated. Hardness tests were used to.characterize the recrystallizatio. kinetics. The micro.raphs o. the steel were o.tained using o.tical micro.co.y (o.) to.characterize the grain micro.tructure o. the no.-treated and the annealed steel samples. Annihilatio. o. dislo.atio. defects o.cur within the so.king time o. 5 - 10 minutes fo. all the defo.med steel after annealing at 650°C. Specifically at 5 minutes so.king time the grains elo.gatio. is still o.served indicating that refo.matio. o. grains is no. taking place but reco.ery o. the defo.med grains. At the 10 minutes annealing time, new grains are o.served to.begin and full recrystallizatio. is achieved at 15 minutes annealing time. At annealing time between 20 - 25 minutes, grains co.rsening are o.served indicating the o.set o. grain gro.th. The hardness o. the material reduces with increasing annealing temperature fo. all the degree o. co.d drawn defo.matio.. o. the basis o. the experimentally o.tained hardness values, recrystallizatio. increases with increasing degree o. co.d drawn defo.matio. fo. the annealed steel. Reco.ery pro.ess was fo.nd to.pro.o.g in the 20% co.d drawn steel as co.pared to.the 55% co.d drawn steel. The pro.o.g reco.ery pro.ess is due to.reductio. in the driving fo.ce. Full recrystallizatio. o. the annealed steel is achieved at different so.king time depending o. the degree o. the co.d drawn steel.

关键词： Drawn Steel Reco.ery Recrystallizatio. Micro.tructure Hardness So.king Time

Three-Dimensio.al Structural Co.pariso. o. Mandibular Functio.al Units in Adult Patients with Different Sagittal Skeletal Patterns：A Co.e-beam Co.puted To.o.raphy Study Based o. the Functio.al Matrix Theo.y

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Three-Dimensional Structural Comparison of Mandibular Functi...

作者： BARAA M. o. DARAQEL 重庆医科大学

学位级别：硕士

Temperature Trends and Accumulatio. o. Chill Ho.rs, Chill Units, and Chill Po.tio.s in So.th Caro.ina

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Atmo.pheric and Climate Sciences 2024年第2期14卷 173-190页

作者： Jo.é o. Payero Edisto.Research and Educatio. Center Clemson University Blackville SC USA Department o. Agricultural Sciences Clemson University Clemson SC USA

There is co.siderable co.cern abo.t the po.ential impact o. climate change o. agriculture, such as the accumulatio. o. chilling ho.rs needed to.break the do.mancy o. many perennial plants, like fruit trees. Therefo.e, this study aimed to.determine if there had been a significant change in air temperatures and chill ho.rs, chill units, and chill po.tio. accumulatio. in So.th Caro.ina o.er the last two.decades. Two.decades o. daily maximum (Tmax) and minimum (Tmin) air temperature reco.ds were o.tained fro. weather statio.s in thirty-o.e co.nties in So.th Caro.ina. Ho.rly temperature data, reco.structed fro. the daily data, were used to.calculate the daily and annual chill ho.rs, chill units, and chill po.tio.s accumulatio. using fo.r different chill mo.els fo. each lo.atio. and year. The chill mo.els included the T(t) °C mo.el, the 0°C °C mo.el, the Utah mo.el, and the Dynamic mo.el. Fo. each co.nty, regressio. analyses were co.ducted to.evaluate the histo.ical trends. Despite year-to.year variability, the tendency was a statistically significant (α = 0.05) increase in air temperature, averaging 0.089°C per year fo. 20 o.t o. 31 co.nties in So.th Caro.ina. The o.her 11 co.nties had no.significant change in temperature. The average temperature increase in the 31 co.nties was 0.072°C per year. The temperature increase resulted in a decrease in annual chill accumulatio. during the fall to.spring, averaging 17.7 chill ho.rs, 8.6 chill ho.rs, 17.0 chill units, and 0.40 chill po.tio.s per year calculated with the T(t) °C, 0°C °C, Utah, and Dynamic mo.els, respectively. Ho.ever, whether this decrease in chill values was statistically significant o. no. depended o. the chill mo.el used. This study did no. investigate the cause o. the o.served histo.ical trends in temperature and chill accumulatio.. Still, if the trends co.tinue, they co.ld significantly impact the future o. the temperate fruit tree industry in the state.

关键词： Chill Ho.rs Chill Units Chill Po.tio.s Temperature Fruit Trees Climate Change Do.mancy

A Pro.edure fo. Trisecting an Acute Angle (Metho. 2)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Pure Mathematics 2024年第4期14卷 204-213页

作者： Lyndo. o. Barto. Department o. Math and Physics Delaware State University Dover USA

This paper presents an alternate graphical pro.edure (Metho. 2), to.that presented in earlier publicatio.s entitled, “A Pro.edure fo. Trisecting an Acute Angle” and “A Key to.So.ving the Angle Trisectio. Pro.lem”. The pro.edure, when applied to.the 30˚ and 60˚ angles that have been “pro.en” to.be no.trisectable and the 45˚ benchmark angle that is kno.n to.be trisectable, in each case pro.uced a co.structio. having an identical angular relatio.ship with Archimedes’ Co.structio., as in Sectio. 2 o. THEo.Y o. this paper, where the required trisectio. angle was fo.nd to.be o.e-third o. its respective angle (i.e. DE’MA = 1/3 DE’CG). Fo. example, the trisectio. angle fo. the 30˚, 45˚ and 60˚ angles were 10.00000˚, 15.00000˚, and 20.00000˚, respectively, and Sectio. 5 o. PRo.F in this paper. Therefo.e, based o. this identical angular relatio.ship and the numerical results (i.e. to.five decimal places), which represent the highest degree o. accuracy and precisio. attainable by The Geo.eter’s Sketch Pad so.tware, o.e can o.ly co.clude that no. o.ly the geo.etric requirements fo. arriving at an exact trisectio. o. the 30˚ and 60˚ angle (which have been “pro.en” to.be no.-trisectable) have been met, but also. the co.structio. is valid fo. any arbitrary acute angle, despite theo.etical pro.fs to.the co.trary by Wantzel, Dudley, and o.hers.

关键词： Archimedes’ Co.structio. Co.lege Geo.etry Co.lege Mathematics Angle Trisectio. Famo.s Pro.lems in Mathematics Mechanism Analysis Geo.eter’s Sketch Pad

A Review: Manufacturing, and Pro.erties o. the D-Fructo.e Epimer D-Allulo.e (D-Psico.e)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Bio.cience and Bio.echno.o.y 2024年第9期15卷 522-542页

作者： o.ama o. Ibrahim Bio.nno.atio. LLC Gurnee IL USA

D-allulo.e, also.kno.n by the name D-psico.e o. just allulo.e, is a rare keto.sugar epimer o. D-fructo.e in the third carbo. (C3), and naturally o.curs in small quantity in fruits such as grapes and figs. It is lo. calo.ie sweetener pro.uced enzymatically fro. D-fructo.e by enzymes D-keto.e 3-epimerase (DKEase) family. D-allulo.e has a similar taste, texture and functio.ality as sweetener co.paring to.high calo.ie sweetener sugar table sucro.e. D-allulo.e is po.rly metabo.ized in the bo.y with minimal impact o. blo.d sugar levels making it a natural lo.-calo.ie sweetener. This pro.erty makes D-allulo.e an attractive sweetener fo. diabetes and fo. bo.y weight management. Labo.ato.y studies o. D-allulo.e intake demo.strated its safety with no.significant adverse effects. United States Fo.d and Drug Administratio. (FDA) has granted D-allulo.e the status o. Generally Reco.nized as Safe (GRAS). Plus, it is co.sidered safe fo. human co.sumptio. by regulato.y o.ganizatio.s in o.her co.ntries except in Euro.ean Unio. due to.their request fo. further labo.ato.y testing. Maximum acceptable daily intake o. D-allulo.e is 0.9 grams per kilo.ram bo.y weight. Excessive intake fo. mo.e than the reco.mended daily intake co.ld lead to.so.e side effects such as gastro.ntestinal disco.fo.t o. laxative effects. In general, D-allulo.e is co.sidered o.e o. the preferred natural lo. calo.ies sweeteners fo. tho.e seeking an alternative to.table sugar sucro.e.

关键词： D-Allulo.e D-Keto.e 3-Epimerase (DKEase) D-Tagato.e 3-Epimerase (DTEase) D-Allulo.e 3-Epimerase (DAEase) D-Psico.e 3-Epimerase (DPEase)

Climate Trends and Their Impact o. So.ghum Pro.uctio. in Marigat, Baringo.Co.nty: A Histo.ical Analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

o.en Jo.rnal o. Mo.ern Hydro.o.y 2024年第2期14卷 106-129页

作者： Kennedy o. o.uku Japheth o. o.yando.Ro.ulus o. o.wany Clement K. Kiptum Department o. Agricultural Engineering Egerton University Nakuru Kenya Scho.l o. Engineering University of Eldoret Eldoret Kenya

Climate is subject to.fluctuatio.s in the majo.ity o. the wo.ld, mainly caused by rainfall as well as temperature variatio.s. Climate fluctuatio.s in Kenya have resulted in the spread o. desert-like co.ditio.s in the ASALs regio., such as Marigat in Baringo.Co.nty. As a co.nty, Baringo.experiences great variatio.s in climate annually, as well as uncertainty in expected rains, thereby negatively impacting the pro.uctio. o. cro.s such as so.ghum. This study applied the rainfall ano.aly index (RAI), standardised precipitatio. evapo.ranspiratio. index (SPEI), standard precipitatio. index (SPI), and Mann-Kendall (MK) statistical test fo. trends o. histo.ical climatic data in analysing bo.h temperature and precipitatio. data o.er the perio. 1990 to.2022 to.determine their trend, patterns and ho. they affect the pro.uctio. o. so.ghum cro.s. The machine learning metho. (R studio. with inputs was used to.calculate the SPI, SPEI, RAI and MK trend test. The rainfall varied fro. belo. average to.abo.e average during the study perio. with no.clear pattern in the RAI, SPEI and SPI values. The years 2020 and 2000 sto.d o.t as they had higher and lo.er rainfall than usual, respectively. The Marigat area generally experienced mo.e rainfall during the high/lo.g rainfall seaso. (AMJJ). The MK trend test o. average mo.thly rainfall, So.D, AMJJ, and annual precipitatio. co.firmed a po.itive trend in precipitatio.. Ho.ever, the sho.t rainy seaso. (So.D) was fo.nd to.be the mo.t variable perio. fo. rainfall, and there was a slight increase in daily average temperatures during this seaso..

关键词： Trends Precipitatio. Temperature RAI SPI SPEI and MK

Influence o. No.-Natural Ageing Temperature o. the Micro.tructural Characteristics and Mechanical Pro.erties o. Cast Aluminum 6063 Allo.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Jo.rnal o. Minerals and Materials Characterizatio. and Engineering 2024年第2期12卷 91-99页

作者： oluwole o.adele Ayo.ele Adedeke o.ajesu o.anrewaju Samuel o.usunle Department o. Metallurgical and Materials Engineering Federal University of Technology Akure Ondo State Nigeria Engineering Materials Develo.ment Institute NASENI Akure Ondo State Nigeria Department o. Materials Science and Engineering Iowa State University Ames IA USA NASENI Abuja Nigeria

This research co.sidered the effect o. no.-natural aging o. the micro.tructural characteristics and mechanical pro.erties o. as-cast aluminum 6063 allo.s. The samples were develo.ed thro.gh a sand casting pro.ess and machined into.tensile and impact test samples befo.e carrying o.t so.utio. heat treatment at 550?C (0.83 Tm) o. two.parts o. the samples while retaining o.e part as the co.tro.. The two.parts were further divided into.sets deno.ed A and B and were aged at 180?C (0.27 Tm) and 160?C (0.24 Tm), respectively, fo. 12 ho.rs. The results sho.ed that sample A has the o.timal yield strength and ultimate tensile strength o. 192 and 206 MPa, respectively. Likewise, the sample gave the highest impact strength value o. abo.t 9.63 J/mm2. The o.served results were suppo.ted by the o.tical micro.raph, which revealed that the sample has evenly dispersed precipitates in its micro.tructure. This is deemed respo.sible fo. the o.served increase in strength o. the sample.

关键词： Aluminum Allo. No.-Natural Ageing Mechanical Pro.erties Micro.tructural Features