A pilot wire drawing machine as well as wire end-pointing roller was developed. Using these machines, a wire drawing test for four different coating materials and two different lubricants was performed as the reductio...A pilot wire drawing machine as well as wire end-pointing roller was developed. Using these machines, a wire drawing test for four different coating materials and two different lubricants was performed as the reduction ratio increased from 10% to 30%. Materials used for a substrate in this study are plain carbon steel （AIS11045） and ultra low carbon bainite steel. To compute the friction coefficient between the coating layer of wire and the surface of die lbr a specific lubricant, a series of finite element analyses were carried out. SEM observations were also conducted to investigate the surface defects of wire deformed. Results show that the behavior of drawing force varies with the lubricant-type at the initial stage of drawing. The powder-typed lubricant with a large particle causes the retardation of lull lubrication on the entire contact surface and the local delamination of coating layer on the wire surface. As the flow stress of a substrate increases, the delamination becomes severe.展开更多
Mechanical properties of galvannealed (GA) steel sheet used for automotive exposed panel and predicted failure phenomenon of its coating layer were evaluated using finite element method. V-bending test was performed t...Mechanical properties of galvannealed (GA) steel sheet used for automotive exposed panel and predicted failure phenomenon of its coating layer were evaluated using finite element method. V-bending test was performed to understand better the fracture of coating layer of GA steel sheet during plastic deformation. Yield strength of the coating layer was calculated by using a relative difference between hardness of coating layer measured from the nano-indentation test and that of substrate. To measure shearing strength at the interface between substrate and coating layer, shearing test with two specimens attached by an adhesive was carried out. Using the mechanical properties measured, a series of finite element analyses coupled with a failure model was performed. Results reveal that the fracture of coating layer occurs in an irregular manner at the region where compressive deformation is dominant. Meanwhile, a series of vertical cracks perpendicular to material surface are observed at the tensile stressed-region. It is found that 0.26-0.28 of local equivalent plastic strain exists at the coating and substrate at the beginning of failure. The fracture of coating layer depends on ductility of the coating layer considerably as well.展开更多
The initial cluster of severe pneumonia cases that triggered the COVID-19 epidemic was identified inWuhan,China in December 2019.While early cases of the disease were linked to a wet market,human-to-human transmission...The initial cluster of severe pneumonia cases that triggered the COVID-19 epidemic was identified inWuhan,China in December 2019.While early cases of the disease were linked to a wet market,human-to-human transmission has driven the rapid spread of the virus throughout China.The Chinese government has implemented containment strategies of city-wide lockdowns,screening at airports and train stations,and isolation of suspected patients;however,the cumulative case count keeps growing every day.The ongoing outbreak presents a challenge for modelers,as limited data are available on the early growth trajectory,and the epidemiological characteristics of the novel coronavirus are yet to be fully elucidated.We use phenomenological models that have been validated during previous outbreaks to generate and assess short-term forecasts of the cumulative number of confirmed reported cases in Hubei province,the epicenter of the epidemic,and for the overall trajectory in China,excluding the province of Hubei.We collect daily reported cumulative confirmed cases for the 2019-nCoV outbreak for each Chinese province from the National Health Commission of China.Here,we provide 5,10,and 15 day forecasts for five consecutive days,February 5th through February 9th,with quantified uncertainty based on a generalized logistic growth model,the Richards growth model,and a sub-epidemic wave model.Our most recent forecasts reported here,based on data up until February 9,2020,largely agree across the three models presented and suggest an average range of 7409e7496 additional confirmed cases in Hubei and 1128e1929 additional cases in other provinces within the next five days.Models also predict an average total cumulative case count between 37,415 and 38,028 in Hubei and 11,588e13,499 in other provinces by February 24,2020.Mean estimates and uncertainty bounds for both Hubei and other provinces have remained relatively stable in the last three reporting dates(February 7th e 9th).We also observe that each of the models predicts that the epidemic has reached saturation in both Hubei and other provinces.Our findings suggest that the containment strategies implemented in China are successfully reducing transmission and that the epidemic growth has slowed in recent days.展开更多
Purpose A 12-lead electrocardiogram(ECG)is a screening tool to detect abnormalities that may predispose athletes to sud-den cardiac death.Newer standardized criteria have been introduced to better interpret ECG data,h...Purpose A 12-lead electrocardiogram(ECG)is a screening tool to detect abnormalities that may predispose athletes to sud-den cardiac death.Newer standardized criteria have been introduced to better interpret ECG data,however this research has predominantly focused on male athletes.It is important to include female athletes in research to better define ECG character-istics in this population.The purpose of this study was to compare the Seattle and International Criteria ECG abnormalities in Division II female collegiate athletes of various ethnicities.Methods Fifty-six females(age 20.2±1.4 years;height 1.70±0.7 m;weight 69.5±8.9 kg)completed a resting 12-lead ECG protocol.ECG data was classified as‘normal’and‘abnormal’according to the parameters of each criterion and abnormal conditions were noted.Chi-square analysis was used to assess statistical comparisons between criteria.Results There was a significant difference in abnormal classifications as the total number of ECGs identified as abnormal using the Seattle Criteria decreased from 12(21.4%)to 2(3.6%)when using the International Criteria(P<0.05).African American athletes had a higher number of abnormal ECG’s compared to White and Latina athletes using the Seattle Criteria(P=0.03).Conclusions The International Criteria significantly reduces the total number of abnormal ECG readings in female collegiate athletes compared to the Seattle Criteria and did not overly identify African American athletes with abnormalities.Further research is necessary to expand on this study and clearly define criteria for female athletes of various ethnicities.展开更多
Purpose Improved resistive plate chambers(iRPCs)will be installed in the challenging forward region of the compact muon solenoid(CMS)during its Phase-2 upgrade.The design target of iRPC time resolution is 1.5 ns.It wi...Purpose Improved resistive plate chambers(iRPCs)will be installed in the challenging forward region of the compact muon solenoid(CMS)during its Phase-2 upgrade.The design target of iRPC time resolution is 1.5 ns.It will help the Level-1 trigger system distinguish the muons from high backgrounds and improve the trigger efficiency.Studying the time resolution after integrating the new backend electronics boards(BEB)is essential for ensuring timely performance.In this system,a time reference(Tref)signal is distributed by the BEB to several frontend electronics boards(FEB)to reset the time-to-digital converters(TDC).In the CMS experiment,the arrangement of the iRPC chambers and on-chamber FEBs is at different positions,resulting in varying Tref arrival times on the FEB side.This paper describes the measures taken to ensure the time resolution of the single path and adjust the time base for multi-paths.Method Unique designs were implemented in the chamber,FEB,and BEB to ensure a satisfactory time resolution.Tref adjustments for different paths were performed in bunch crossing steps(24.950 ns)in the BEB using shift registers.And the sub-bunch crossing adjustment steps were performed in the FEB using the TDC correction module.Finally,the arrival time differences of Tref on different FEBs were less than 1.25 ns after adjustment.Results The time resolution of the FEB–BEB system was observed to be 32 ps.The time resolution of the chamber FEB–BEB system was first measured and is 554 ps at an iRPC working point of 7200 V.In addition,the Tref arrival time differences of different paths were adjusted from−99.923(−90.113)ns to 0.073(−0.141)ns.Conclusion The test results revealed that the system time resolution and Tref adjustment performed by the BEB met the Phase-2 upgrade goals.展开更多
基金supported by research funds from Dong-A University, Korea
文摘A pilot wire drawing machine as well as wire end-pointing roller was developed. Using these machines, a wire drawing test for four different coating materials and two different lubricants was performed as the reduction ratio increased from 10% to 30%. Materials used for a substrate in this study are plain carbon steel （AIS11045） and ultra low carbon bainite steel. To compute the friction coefficient between the coating layer of wire and the surface of die lbr a specific lubricant, a series of finite element analyses were carried out. SEM observations were also conducted to investigate the surface defects of wire deformed. Results show that the behavior of drawing force varies with the lubricant-type at the initial stage of drawing. The powder-typed lubricant with a large particle causes the retardation of lull lubrication on the entire contact surface and the local delamination of coating layer on the wire surface. As the flow stress of a substrate increases, the delamination becomes severe.
基金supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2009-0074936)
文摘Mechanical properties of galvannealed (GA) steel sheet used for automotive exposed panel and predicted failure phenomenon of its coating layer were evaluated using finite element method. V-bending test was performed to understand better the fracture of coating layer of GA steel sheet during plastic deformation. Yield strength of the coating layer was calculated by using a relative difference between hardness of coating layer measured from the nano-indentation test and that of substrate. To measure shearing strength at the interface between substrate and coating layer, shearing test with two specimens attached by an adhesive was carried out. Using the mechanical properties measured, a series of finite element analyses coupled with a failure model was performed. Results reveal that the fracture of coating layer occurs in an irregular manner at the region where compressive deformation is dominant. Meanwhile, a series of vertical cracks perpendicular to material surface are observed at the tensile stressed-region. It is found that 0.26-0.28 of local equivalent plastic strain exists at the coating and substrate at the beginning of failure. The fracture of coating layer depends on ductility of the coating layer considerably as well.
基金GC is supported by NSF grants 1610429 and 1633381.
文摘The initial cluster of severe pneumonia cases that triggered the COVID-19 epidemic was identified inWuhan,China in December 2019.While early cases of the disease were linked to a wet market,human-to-human transmission has driven the rapid spread of the virus throughout China.The Chinese government has implemented containment strategies of city-wide lockdowns,screening at airports and train stations,and isolation of suspected patients;however,the cumulative case count keeps growing every day.The ongoing outbreak presents a challenge for modelers,as limited data are available on the early growth trajectory,and the epidemiological characteristics of the novel coronavirus are yet to be fully elucidated.We use phenomenological models that have been validated during previous outbreaks to generate and assess short-term forecasts of the cumulative number of confirmed reported cases in Hubei province,the epicenter of the epidemic,and for the overall trajectory in China,excluding the province of Hubei.We collect daily reported cumulative confirmed cases for the 2019-nCoV outbreak for each Chinese province from the National Health Commission of China.Here,we provide 5,10,and 15 day forecasts for five consecutive days,February 5th through February 9th,with quantified uncertainty based on a generalized logistic growth model,the Richards growth model,and a sub-epidemic wave model.Our most recent forecasts reported here,based on data up until February 9,2020,largely agree across the three models presented and suggest an average range of 7409e7496 additional confirmed cases in Hubei and 1128e1929 additional cases in other provinces within the next five days.Models also predict an average total cumulative case count between 37,415 and 38,028 in Hubei and 11,588e13,499 in other provinces by February 24,2020.Mean estimates and uncertainty bounds for both Hubei and other provinces have remained relatively stable in the last three reporting dates(February 7th e 9th).We also observe that each of the models predicts that the epidemic has reached saturation in both Hubei and other provinces.Our findings suggest that the containment strategies implemented in China are successfully reducing transmission and that the epidemic growth has slowed in recent days.
文摘Purpose A 12-lead electrocardiogram(ECG)is a screening tool to detect abnormalities that may predispose athletes to sud-den cardiac death.Newer standardized criteria have been introduced to better interpret ECG data,however this research has predominantly focused on male athletes.It is important to include female athletes in research to better define ECG character-istics in this population.The purpose of this study was to compare the Seattle and International Criteria ECG abnormalities in Division II female collegiate athletes of various ethnicities.Methods Fifty-six females(age 20.2±1.4 years;height 1.70±0.7 m;weight 69.5±8.9 kg)completed a resting 12-lead ECG protocol.ECG data was classified as‘normal’and‘abnormal’according to the parameters of each criterion and abnormal conditions were noted.Chi-square analysis was used to assess statistical comparisons between criteria.Results There was a significant difference in abnormal classifications as the total number of ECGs identified as abnormal using the Seattle Criteria decreased from 12(21.4%)to 2(3.6%)when using the International Criteria(P<0.05).African American athletes had a higher number of abnormal ECG’s compared to White and Latina athletes using the Seattle Criteria(P=0.03).Conclusions The International Criteria significantly reduces the total number of abnormal ECG readings in female collegiate athletes compared to the Seattle Criteria and did not overly identify African American athletes with abnormalities.Further research is necessary to expand on this study and clearly define criteria for female athletes of various ethnicities.
基金supported in part by the National Key R&D Program of China(No.2022YFA1602101)the National Natural Science Foundation of China(No.12035018)+26 种基金We would also like to acknowledge the enduring support for the CMS Phase-2 upgrade and the supporting computing infrastructure provided by the following funding agencies:FWO(Belgium)CNPq(Brazil),CAPES(Brazil)FAPERJ(Brazil)MES(Bulgaria)BNSF(Bulgaria)CERNCAS(China)MoST(China)MINCIENCIAS(Colombia)CEA(France)CNRS/IN2P3(France)SRNSFG(Georgia)[YS-21-1798]DAE(India)DST(India)IPM(Iran)INFN(Italy)MSIP(Republic of Korea)NRF(Republic of Korea)BUAP(Mexico)CINVESTAV(Mexico)CONACYT(Mexico)LNS(Mexico)SEP(Mexico)UASLP-FAI(Mexico)PAEC(Pakistan)DOE(USA)NSF(USA).
文摘Purpose Improved resistive plate chambers(iRPCs)will be installed in the challenging forward region of the compact muon solenoid(CMS)during its Phase-2 upgrade.The design target of iRPC time resolution is 1.5 ns.It will help the Level-1 trigger system distinguish the muons from high backgrounds and improve the trigger efficiency.Studying the time resolution after integrating the new backend electronics boards(BEB)is essential for ensuring timely performance.In this system,a time reference(Tref)signal is distributed by the BEB to several frontend electronics boards(FEB)to reset the time-to-digital converters(TDC).In the CMS experiment,the arrangement of the iRPC chambers and on-chamber FEBs is at different positions,resulting in varying Tref arrival times on the FEB side.This paper describes the measures taken to ensure the time resolution of the single path and adjust the time base for multi-paths.Method Unique designs were implemented in the chamber,FEB,and BEB to ensure a satisfactory time resolution.Tref adjustments for different paths were performed in bunch crossing steps(24.950 ns)in the BEB using shift registers.And the sub-bunch crossing adjustment steps were performed in the FEB using the TDC correction module.Finally,the arrival time differences of Tref on different FEBs were less than 1.25 ns after adjustment.Results The time resolution of the FEB–BEB system was observed to be 32 ps.The time resolution of the chamber FEB–BEB system was first measured and is 554 ps at an iRPC working point of 7200 V.In addition,the Tref arrival time differences of different paths were adjusted from−99.923(−90.113)ns to 0.073(−0.141)ns.Conclusion The test results revealed that the system time resolution and Tref adjustment performed by the BEB met the Phase-2 upgrade goals.
