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Multiscale approach to micro/macro fatigue crack growth in 2024-T3 aluminum panel

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Science China(Physics,Mechanics & Astronomy) 2014年第1期57卷 51-58页

作者： sih G.C. International Center for Sustainability Accountability and Eco-Affordability of the Large and Small (ICSAELS) Lehigh UniversityBethlehem PA 18015 USA Key Laboratory of Pressure Systems and Safety Ministry of Education School of Mechanical Engineering East China University of Science and Technology

When two contacting solid surfaces are tightly closed and invisible to the naked eye, the discontinuity is said to be microscopic regardless of whether its length is short or long. By this definition, it is not sufficient to distinguish the difference between a micro- and macro-crack by using the length parameter. Microcracks in high strength metal alloys have been known to be sev- eral centimeters or longer. Considered in this work is a dual scale fatigue crack growth model where the main crack can be mi- cro or macro but there prevails an inherent microscopic tip region that is damaged depending on the irregularities of the micro- structure. This region is referred to as the ＂micro-tip＂ and can be simulated by a sharp wedge with different angles in addition to mixed boundary conditions. The combination is sufficient to model microscopic entities in the form of voids, inclusions, precipitations, interfaces, in addition to subgrain imperfections, or cluster of dislocations. This is accomplished by using the method of ＂singularity representation＂ such that closed form asymptotic solutions can be obtained for the development of fa- tigue crack growth rate relations with three parameters. They include：（1） the crack surface tightness o-＊ represented by Cro/Cr~ = 0.3-0.5 for short cracks in region I, and 0.1-0.2 for long cracks in region II, （2） the micro/macro material properties reflected by the shear modulus ratio/1＂（=,L/micro/]-/macro varying between 2 and 5） and （3） the most sensitive parameter d＊ being the micro-tip characteristic length d＊（=d/do） whose magnitude decreases in the direction of region I ---~II. The existing fatigue crack growth data for 2024-T3 and 7075-T6 aluminum sheets are used to reinterpret the two-parameter da/dN=C（AK）n relation where AK has now been re-derived for a microcrack with surfaces tightly in contact. The contact force will depend on the mean stress ~m or mean stress ratio R as the primary parameter and on the stress amplitude era

关键词： microcrack macrocrack microstructure singularity multiscaling scale shift micro/macro crack growth 7075-T6 and 2024-T3

Application of supersonic particle deposition to enhance the structural integrity of aircraft structures

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Science China(Physics,Mechanics & Astronomy) 2014年第1期57卷 12-18页

作者： Matthews N. Jones R. sih G.C. Rosebank Engineering Australia 836 Mountain Highway Bayswater VIC 315 Australia Centre of Expertise in Structural Mechanics Department of Mechanical and Aeronautical Engineering Monash UniversityWellington Rd Clayton Vic 3800 Australia Centre of Sustainability Accountability and Eco-Affordability for Large and Small Structures Lehigh University BethlehemPennsylvania USA

Aircraft metal components and structures are susceptible to environmental degradation throughout their original design life and in many cases their extended *** paper summarizes the results of an experimental program to evaluate the ability of Supersonic Particle Deposition(SPD),also known as cold spray,to extend the limit of validity(LOV)of aircraft structural components and to restore the structural integrity of corroded *** this study the potential for the SPD to seal the mechanically fastened joints and for this seal to remain intact even in the presence of multi-site damage(MSD)has been *** sealing the joint the onset of corrosion damage in the joint can be significantly retarded,possibly even eliminated,thereby dramatically extending the LOV of mechanically fastened *** study also shows that SPD can dramatically increase the damage tolerance of badly corroded wing skins.

关键词： cold spray fuselage joints corrosion LOV

3C DUCT DESIGN METHOD

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Acta Mechanica Sinica 2002年第2期18卷 67-74页

作者： Huan-RueiShiu Feng-ChuOu sih-LiChen DepartmentofMechanicalEngineeringNationalTaiwanUniversityTaipei Taiwan10617R.O.C.

A new 3C duct design method is proposed for designing a high quality, energy-efficiency cost-effective air duct system. It not only considers the demand of volume flow rate, but also takes into consideration a number of issues including system pressure balance, noise, vibration, space limitation and total system cost. This new method comprises three major calculation procedures:initial computer-aided design (CAD), computer-aided simulation (CAS) and correction processes (CP). An example is presented in this study to understand the characteristics of 3C method. It shows that 3C duct design method provides a simple computation procedure for an optimum air duct system. It also shortens the design schedule, prevents human calculation errors, and reduces the dependence on designer experience. In addition to apply in a new duct system design, 3C duct design method is also a powerful design tool for the expansion of an existing duct system.

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环腺苷二磷酸核糖(cADPR)的化学与生物学研究(英文)

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有机化学 1997年第1期17卷 43-46页

作者： CharlesJ.sih Shini Yamada School of Pharmacy University of Wisconsin - Madison Madison WI 53706 425 N. Charter Street United States

通过立体选择环化βNAD实现了cADPR的生物模拟合成,并用这一方法合成了一系列cADPR类似物。类似物之一,cATP在鼠脑微粒体中释放Ca^(2+)的能力比cADPR强25倍。Aplysia环合酶和NAD酶皆可环合NADP^+而生成。cADPRP。cADPRP调节Ca^(2+)释放... 详细信息

通过立体选择环化βNAD实现了cADPR的生物模拟合成,并用这一方法合成了一系列cADPR类似物。类似物之一,cATP在鼠脑微粒体中释放Ca^(2+)的能力比cADPR强25倍。Aplysia环合酶和NAD酶皆可环合NADP^+而生成。cADPRP。cADPRP调节Ca^(2+)释放的能力比cADPR强2倍。用亲和柱方法,从鼠脑中分离得到了cADPR结合蛋白(36kDa)和cADPRP结合蛋白(40kDa)。

关键词： cADPR 结合蛋白化学生物学

Polymer Modified Concrete of Blended Cement and Natural Latex Copolymer: Static and Dynamic Analysis

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Open Journal of Civil Engineering 2018年第2期8卷 205-220页

作者： sih Wuri Andayani Rochim Suratman Iswandi Imran Mardiyati Material Engineering Bandung Institute of Technology Bandung Indonesia Centre for Material and Technical Product Ministry of Industry Bandung Indonesia Civil Engineering Bandung Institute of Technology Bandung Indonesia

This paper deals with the effect of blended cement and natural latex copolymer to static and dynamic properties of polymer modified concrete. The polymer was used copolymer of natural latex methacrylate (KOLAM) and copolymer of natural latex styrene (KOLAS) with composition of 1%, 5%, and 10% w/w of weight of blended cement in concrete mixture. They are tested for compressive strength, flexural strength, splitting tensile strength, and modulus elasticity for static analysis, and impact load and energy dissipation profile for dynamic analysis. The result shows that KOLAM with concentration 1% give better performance in static and dynamic properties. The KOLAM 1% gives improvement in flexural strength, splitting tensile strength and modulus elasticity about 4%, 13% and 3% compared to normal concrete. And for dynamic properties, KOLAM 1% could reduce impact load up to 35% and improve energy dissipation capacity about 45% compared to normal concrete. The concentration of KOLAM higher than 1% resulting negative effect to static and dynamic properties, except modulus of elasticity. For KOLAS, there were no positive trends of static and dynamic properties.

关键词： Blended Cement Dynamic Properties Polymer Modified Concrete KOLAM KOLAS Static Properties

Temperature Effect Investigation toward Peat Surface CO2 Emissions by Planting Leguminous Cover Crops in Oil Palm Plantations in West Kalimantan

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Journal of Agricultural Science and Technology(B) 2015年第3期5卷 170-183页

作者： Arifin Suntoro Wongso Atmojo Prabang Setyono Widyatmani sih Dewi Environmental Engineering Department Tanjungpura University Pontianak 78124 Indonesia Agriculture Faculty Sebelas Maret University Surakarta 57126 Indonesia Environmental Science Postgraduate Program Sebelas Maret University Surakarta 5 7126 Indonesia Agriculture Postgraduate Program Sebelas Maret University Surakarta 5 7126 Indonesia

The aim of this research was to know the impact of planting leguminous cover crops （LCCs） of Mucuna bracteata and Calopogonium mucunoides in oil palm plantation on peatland on reducing CO2 emissions. Atmosphere temperature, peat surface temperature, in-closed chamber temperature and peat surface CO2 fluxes were monitored on two adjacent experimental plots. The first experimental plot was on the newly opened peat surface （NOPS） and another was on the eight years planted oil palm land （EPOL）. The closed chamber techniques adopted from International Atomic Energy Agency （IAEA）（1993） were implemented to trap CO2 emissions emitted from 24 treatment plots at the 1st, 3rd and 6th months observations. Average CO2 fluxes observed on no LCCs plots in the NOPS site were 61.25 ± 8.98, 33.76 ± 2.92 and 33.75 ± 3.45 g/m2.h, while in the EPOL site were 55.38 ± 15.95, 29.90 ± 5.32 and 27.70 ± 4.62 g/mLh at the 1st, 3rd and 6th months monitoring, respectively. Average CO2 fluxes observed on the planted M. bracteata plots in the NOPS site were 68.2 ± 24.5, 12.88 ± 3.70 and 10.40 ± 1.28 g/m2.h, whereas in the EPOL site were 54.04 ± 6.70, 11.45 ± 2.00 and 9.33 ± 3.49 g/m2.h at the 1st, 3rd and 6th months monitoring, respectively. Average CO2 flux observed on the planted C. mucunoides plots in the NOPS site were 66.5 ± 23.7, 15.41 ± 1.51 and 9.74 ± 2.55 g/m2.h, while in the EPOL site were 47.00 ± 5.00, 9.34 ± 1.23 and 10.52 ± 4.80 g/m2.h at the 1st, 3rd and 6th months, respectively. P-value for the experimental sites was 0.008 （〈 0.05）, indicating the significant difference in the level of CO2 fluxes between the sites. P-value for the treatments in the experimental plots was 0.000 （〈 0.05）, indicating markedly different level of CO2 fluxes among treatments. P-value for the age ofM. bracteata and C. mucunoides planted on the experimental plots was 0.000 （〈 0.05）, indicating the significant difference in the level of CO2 fluxes due to the enhanced LCCs age performing at the increase of s

关键词： Temperature peat surface CO2 emissions Mucuna bracteata Calopogonium mucunoides.

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Foreword

Science China(Physics,Mechanics & Astronomy) 2014年第1期57卷 1-1页

作者： sih George C. HOng YouShi Lehigh University Institute of Mechanics Chinese Academy of Sciences

Aviation safety is the theme given to the International Conference on Airworthiness and Fatigue:7thICSAELS Series Conference,Beijing,China,held on 25–27 March,*** event was initiated by the International Center of Sustainability,Accountability,and Eco-Affordability for Large and Small(ICSAELS)and the Institute of Mechanics,Chinese Academy of Sciences.

关键词：可持续发展力学研究所国际会议航空安全承受能力国际中心适航性中国

Vulnerability assessment: A comparison of three different city sizes in the coastal area of Central Java, Indonesia

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Advances in Climate Change Research 2017年第4期8卷 286-296页

作者： Wiwandari HANDAYANI Iwan RUDIARTO Jawoto sih SETYONO Uchendu Eugene CHIGBU Annisa Mu'awanah SUKMAWATI Department of Urban and Regional Planning University of Diponegoro Semarang 50275 Indonesia Institute of Geodesy Geoinformatics and Land Management Technical University of Munich Munich 80333 Germany Department of Urban and Regional Planning University of Technology Yogyakarta Yogyakarta 55164 Indonesia

Considering the importance of connecting urbanization phenomena and vulnerability assessments, this paper aims to explore vulnerability assessment in three different city sizes in the northern coast of Central Java province of Indonesia. It compares the vulnerability levels of the three cities based on their sizes (that is, levels of urbanization). It uses the most current secondary data from the lowest administrative levels,called as kelurahan (urban village), for its assessment. There are two indexes used to indicate their vulnerability levels, namely exposure and sensitivity index (ESI) and adaptive capacity index (ACI). By combining the ESI and ACI, the study found that the kelurahans in Tegal (the medium sized city) have similar vulnerability levels. The kelurahans in Semarang (as the big city) have more combination of vulnerability levelsdindicating that the city has various sensitivity, exposure, as well as adaptive capacity among its kelurahans. In Lasem (the small sized city), due to limitations imposed by adaptationdmostly because of lack of public services and high dependency on primary economic sectorsdall of its kelurahans were found to be vulnerable. The study therefore concluded that the bigger a city is, the more the different areas of that city will have varying levels of vulnerability, leading to a high propensity of vulnerability among its inhabitants. On the other hand, the smaller a city is, the less capacity it will have in reducing its emerging vulnerability challenges.

关键词： Central Java Climate change Indonesia Vulnerability assessment

Diversity of Stingless Bees Based on Principal Component Analysis in Halmahera Island,Indonesia

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Journal of Agricultural Science and Technology(A) 2019年第4期9卷 262-268页

作者： Hearty Salatnaya Asnath Maria Fuah Cece Sumantri Widiatmaka sih Kahoho Department of Animal Production and Technology Faculty of Animal ScienceIPB UniversityBogor 16680Indonesia Department of Soil Science and Land Resources Faculty of AgricultureIPB UniversityBogor 16680Indonesia Research Center for Biology Indonesian Institute of SciencesCibinong 16911Indonesia Agrotechnology Study Program Banau Tertiary Institute of Agricultural EnterpriseWest Halmahera 97752Indonesia

Tetragonula is one of stingless bees genus widely spread in Indo-Pacific with various species,including *** genus is also found in West Halmahera,but it does not have a unique character as the marker,so it is difficult to *** best way to identify is by measuring the body part from each *** research was conducted to analyze morphometry to know the diversity of stingless bee in West *** hundred thirty-two(332)stingless bees from 51 colonies of three different species were used,namely Tetragonula clypearis,40 colonies(252 bees),***,10 colonies(72 bees),and ***,one colony(eight bees).Morphometry of stingless bees were analyzed based on principal component analysis(PCA),visualized into scree plot,score plot,loading plot and *** results showed that only two principal components(PCs)on eigenvalue have a score more than one with the total proportions are 85.8%.All the species were not correlated because they appeared in different *** variables have a positive correlation with ***,but negative correlation with ***,while *** has a weak correlation with the variables of *** can only be found in the highlands,*** is mostly found in medium elevations but can also be found in highlands,while *** can only be found in lowlands.

关键词： Morphometry Tetragonula elevation Halmahera Island