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Elimination of Quench cracking by controlling Agitation Uniformity

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材料热处理学报 2004年第5期25卷 457-461页

作者： cANALE Lauralice c.f TOTTEN George E Departamento de Materials Automobilistica e Aerondutica da EESC da Universidade de Sao Paulo - USP Sao Carlos SP BrazilPortland State University USA

Uniform agitation of the quenchant is a critically important control parameter in optimizing distortion control and reducing steel cracking. Quenching with ultrasonic agitation or in the presence of electrical and magnetic fields provide uniform agitation leading to improved uniformity of the stress fields within the metal not readily achievable with more traditional agitation methods such as propeller pumps and sprays. These methods provide the additional potential advantage of varying agitation throughout the cooling cycle to achieve a wide range of cooling profiles not readily achievable with quenchants and more traditional agitation systems currently in use.

关键词：热处理淬火裂纹搅拌均匀性超声搅拌

Hot cracking in AZ31 and AZ61 Magnesium Alloy

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Journal of Materials Science & Technology 2011年第7期27卷 633-640页

作者： c.J. Huang c.M. cheng c.P. chou f.H. chen Department of Mechanical Engineering National Chiao Tung University Hsinchu 300 Taiwan China Department of Industrial Education National Taiwan Normal University Taipei 106 Taiwan China

This paper examined the impact of the number of thermal cycles and augmented strain on hot cracking in AZ31 and AZ61 magnesium alloy. Statistical analyses were performed. following observation using a scanning electron microscope （SEM）, an energy dispersive spectrometer （EDS） was used for component analysis. Results showed that Al content in magnesium alloy has an effect on hot cracking susceptibility. In addition, the nonequilibrium solidification process produced segregation in Al content, causing higher liquid Mg-alloy rich Al content at grain boundaries, and resulting into liquefied grain boundaries of partially melted zone （PMZ）. In summary, under multiple thermal cycles AZ61 produced serious liquation cracking. AZ61 has higher （6 wt%） Al content and produced much liquefied Mg17Al12 at grain boundaries under multiple thermal cycles. The liquefied Mg17Al12 were pulled apart and hot cracks formed at weld metal HAZ due to the augmented strain. Since AZ31 had half the Al content of AZ61, its hot-cracking susceptibility was lower than AZ61. In addition, AZ61 showed longer total crack length （TcL） in one thermal cycle compared to that in three thermal cycles. This phenomenon was possibly due to high-temperature gasification of Al during the welding process, which resulted in lower overall Al content. consequently, shorter hot cracks exhibited in three thermal cycles. It was found the Al content of AZ31 and AZ61 can be used to assess the hot-cracking susceptibility.

关键词： Varestraint test Thermal cycles Hot-cracking susceptibility Gas tungsten arc welding (GTAW) AZ31 AZ61

Development of Soda Residue concrete Expansion Agent

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Journal of Wuhan University of Technology(Materials Science) 2003年第3期18卷 79-82页

作者：王宝民 M f Mohd Zain f c Lai Department of civil Engineering Dalian University of Technology faculty of Engineering U.K.M (Malaysia)

A new type of concrete expansion agent has been successfully developed for the first time in the world by utilizing an industrial waste residue soda residue and an industrial *** 3%-6% of the agent into Portland cement enables a shrinkage compensating concrete to be *** and concrete containing this expansion agent have better shrinkage compensating and mechanical *** raw materials component,production process,technical properties,micro analysis of mortar made with this expansion agent,mechanism of expansion and research results are described in this *** experimental results show that the new type of concrete expansion agent accords with the standard and its main mineral component is xcaO ySO 3 zAl 2O 3.

关键词： industrial waste soda residue concrete expansion agent expansive concrete shrinkage compensating concrete

Sub-stoichiometric functionally graded titania fibres for water-splitting applications

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Journal of Semiconductors 2015年第6期36卷 11-16页

作者： Vaia Adamaki A.Sergejevs c.clarke f.clemens f.Marken c.R.Bowen Mechanical Engineering Department University of Bath Electronic and Electrical Engineering Department University of Bath High Performance ceramics EMPA Materials Science and Technology chemistry Department University of Bath

The photo-electro-chemical （PEc） splitting of water requires semiconductor materials with a minimum energy gap of 1.23 eV along with conduction and valence bands overlapping the oxidation of H20 and reduction of H＋ respectively. This work overcomes the limitations of stoichiometric titania by manufacturing fine scale fibres that exhibit a compositional gradient of oxygen vacancies across the fibre length. In such a fibre configuration the fibre end that is chemically reduced to a relatively small extent performs as the photoanode and the oxygen vacan- cies enhance the absorption of light. The fibre end that is reduced the most consists of Magn61i phases and exhibits metallic electrical conductivity that enhances the electron-hole separation. The structure and composition of the functionally graded fibres, which were manufactured through extrusion, pressureless sintering and carbo-thermal reduction, are studied using XRD and electron microscopy. Electrochemical impedance spectroscopy measure- ments were performed in a three-electrode electrochemical system and showed that the oxygen vacancies in the functionally graded fibres affect the fiat band potential and have increased carrier density. The efficiency of the system was evaluated with PEc measurements that shows higher efficiency for the functionally graded fibres com- pared to homogeneous TiO2 or Magn61i phase fibres. The functionally graded and fine scale fibres have the potential to be used as an array of active fibres for water splitting applications.

关键词： titania suboxides water splitting photocurrent

Liquid Jet Impingement Heat Transfer with or without Boiling

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Journal of Thermal Science 1993年第1期2卷 32-49页

作者： c.f.Ma T.Gomi 等 DepartmentofThermalScienceandEngineering BeijingPolytechnicUniversityBeijing100022China Departmento

The purpose of this paper is to summarize the important studies in the area of impingement heat transfer with or without phase change, with emphasis on the research conducted at Beijing Polytechnic University mainly with circular jets. Heat transfer characteristics of single phase jets are discussed in detail. comment is presented on boiling heat transfer of impinging jets for steady and transient states. Some special colling configurations of two-phase jets are also introduced.

关键词： impingement heat transfer single phase phase change steady state transient state.

Importance of Air-Sea coupling in Simulating Tropical cyclone Intensity at Landfall

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Advances in Atmospheric Sciences 2022年第10期39卷 1777-1786页

作者： charlie c.f.LOK Johnny c.L.cHAN Ralf TOUMI School of Energy and Environment City University of Hong KongHong KongChina Department of Physics Imperial CollegeLondon SW72AZUK

An atmosphere-only model system for making seasonal prediction and projecting future intensities of landfalling tropical cyclones(Tcs)along the South china coast is upgraded by including ocean and wave models.A total of 642 Tcs have been re-simulated using the new system to produce a climatology of Tc intensity in the South china *** comparisons of the simulations from the atmosphere-only and the fully coupled systems reveal that the inclusion of the additional ocean and wave models enable differential sea surface temperature responses to various Tc characteristics such as translational speed and *** particular,interaction with the ocean does not necessarily imply a weakening of the Tc,with the coastal bathymetry possibly playing a role in causing a near-shore intensification of the *** results suggest that to simulate the evolution of Tc structure more accurately,it is essential to use an air-sea coupled model instead of an atmosphere-only model.

关键词： tropical cyclone intensity tropical cyclone landfall seasonal prediction air-sea coupling

Lipopolysaccharide immune stimulation but not β-mannanase supplementation affects maintenance energy requirements in young weaned pigs

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Journal of Animal Science and Biotechnology 2018年第4期9卷 901-916页

作者： Nichole f.Huntley c.Martin Nyachoti John f.Patience Department of Animal Science Iowa State University Department of Animal Science University of Manitoba

Background: Pathogen or diet-induced immune activation can partition energy and nutrients away from growth,but clear relationships between immune responses and the direction and magnitude of energy partitioning responses have yet to be elucidated. The objectives were to determine how β-mannanase supplementation and lipopolysaccharide(LPS) immune stimulation affect maintenance energy requirements(MEm) and to characterize immune parameters, digestibility, growth performance, and energy ***: In a randomized complete block design, 30 young weaned pigs were assigned to either the control treatment(cON; basal corn, soybean meal and soybean hul s diet), the enzyme treatment(ENZ; basal diet + 0.056% β-mannanase),or the immune system stimulation treatment(ISS; basal diet + 0.056% β-mannanase, chal enged with repeated increasing doses of Escherichia coli LPS). The experiment consisted of a 10-d adaptation period, 5-d digestibility and nitrogen balance measurement, 22 h of heat production(HP) measurements, and 12 h of fasting HP measurements in indirect calorimetry chambers. The immune chal enge consisted of 4 injections of either LPS(ISS) or sterile saline(cON and ENZ), one every48 h beginning on d 10. Blood was collected pre-and post-challenge for complete blood counts with differential,haptoglobin and mannan binding lectin, 12 cytokines, and glucose and insulin ***: Beta-mannanase supplementation did not affect immune status, nutrient digestibility, growth performance,energy balance, or MEm. The ISS treatment induced fever, elevated proinflammatory cytokines and decreased leukocyte concentrations(P ct nitrogen balance or nutrient digestibility(P > 0.10),but increased total HP(21%) and MEm(23%), resulting in decreased lipid deposition(-30%) and average daily gain(-18%)(P conclusions: This experiment provides novel data on β-mannanase supplementation effects on immune parameters and energy balance i

关键词： Acute phase proteins β-Mannan cytokines Digestibility feed induced immune response Heat production Inflammation Lipopolysaccharide Nitrogen balance Swine

Precipitation on stacking faults in Mg–9.8wt%Sn alloy

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Journal of Materials Science & Technology 2020年第10期42卷 230-240页

作者： c.Q.Liu c.He H.W.chen J.f.Nie International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing400044China Department of Materials Science and Engineering Monash UniversityVictoria3800Australia Electron Microscopy center Chongqing UniversityChongqing400044PR China

In this work,we have systematically investigated precipitation ofβ’-Mg3Sn phase on intrinsic stacking faults I1 and I2 in a Mg-9.8 wt%Sn alloy using aberration-corrected scanning transmission electron *** observed I1 faults are generated by the dissociation of c+a perfect dislocations and bounded by frank partial dislocations having a Shockley *** ofβ’on I1 involves a shear of 1/3α,similar to its formation directly from theα-Mg ***β’phase often nucleates at one end of an I1 fault due to the interaction between shear strain fields ofβ’and the Shockley component of the frank partial at that end,and subsequently grows towards the other end of the *** theβ’reaches to the other end,the Shockley partial bounding the lengthening end of theβ’reacts with the frank partial bounding the fault,generating an a perfect dislocation that can glide away from the precipitate and the *** observed I2 faults are generated by the dissociation of a perfect dislocations and bounded by Shockley *** ofβ’on I2 does not need a shear of 1/3α,since the pre-existing I2 fault already provides an ABcA four-layer structure ofβ’.Thickening of theβ’that has already formed on the I2 involves the successive occurrence of three crystallographically equivalent shears of 1/3αon every second(0002)αplane of theα-Mg *** this thickening mechanism is similar to that of theβ’formed directly from theα-Mg matrix,an a perfect dislocation will be produced when theβ’is thickened to eight layers,and it can again glide away from the precipitate and the fault.

关键词： Heterogeneous precipitation HAADf-STEM Shockley partial dislocation frank partial dislocation Dislocation reaction

Early Results of Urothelial carcinoma Screening in a Risk Population of coke Workers:Urothelial carcinoma among coke Workers

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Biomedical and Environmental Sciences 2010年第4期23卷 300-304页

作者： GIBERTI c GALLO f ScHENONE M GENOVA A Department of Surgery Division of Urology San Paolo Hospital Savona Italy Service of Industrial Medicine Italiana Coke Industry S.r.l

Objective To present the protocol and the early results of a urothelial carcinoma （Uc） screening analysis performed in a risk population of coke workers. Methods Between June 2006 and October 2008, 171 male workers （mean age 43 years）, employed in a Ligurian coke plant （Italiana coke S.r.l） and exposed to polycyclic aromatic hydrocarbons （PAHs） for a median period of 16 years, underwent screening for Uc. Urological evaluation included medical history, physical examination, routine laboratory tests, urine analysis, urinary cytology and ucyt＋ assay. In the event of signs and symptoms suggestive of Uc or positive urinary tests, the workers were also subjected to urinary ultrasonography and cystoscopy with biopsy of any suspicious lesions. Results Regarding the laboratory tests, 19/171 （11%） ucyt＋ samples were considered inadequate and were excluded from the outcomes assessment. Overall, urine analysis, cytology and ucyt＋ were positive in 18/152 （12%） subjects who showed no evidence of Uc at the scheduled check-ups. No significant association was identified between marker positivity and occupational activity. conclusions Our results fail to show an increased risk of Uc among the coke workers evaluated. However, they will need to be confirmed in the future by a larger enrollment and a longer follow-up in order to assess the definitive risk for Uc after exposure to coke.

关键词： Bladder cancer Screening Occupation Risk factor Urinary markers