Coronavirus is a Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) caused by a novel coronavirus belonging to the family Coronaviridae. The disease was first discovered in December 2019 in Wuhan City, Hubei...Coronavirus is a Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) caused by a novel coronavirus belonging to the family Coronaviridae. The disease was first discovered in December 2019 in Wuhan City, Hubei Province, China. A few months later, the disease spread all over the world and became an epidemic. The infection for most people is mild to moderate but in Vulnerable groups, if they have the infections, they might experience severe COVID-19. Saudi Arabia initiated its response plan early, and all sectors and agencies worked in an integrated way to combat the disease. It has maintained proper communication during the pandemic and ensured community involvement, epidemiologic surveillance, and activation of rapid response teams. The COVID-19 pandemic significantly affected daily lives. Schools and daycares were closed, education was online, traveling stopped, work was suspended, gathering in social activities and practicing religious rituals, like praying or doing Umrah or Hajj, were banded. Changing lifestyles as a response to COVID-19 impacted whole communities with different categories of children, parents, and families. Women usually take the majority of daily responsibilities. The sudden change in lifestyle during COVID-19 put pressure on mothers, especially those who are working to balance work and family obligations. This study aims to identify the impact of Coronavirus disease 2019 on working mothers in Saudi Arabia. Method: Data of the study was collected through survey posted on social media and analyzed through Excel. It focuses on five aspects: health, lifestyle, social relations, work production and financial status. Our target population was working mothers in Saudi Arabia aged at least 25 years. Results: In this study, all factors affected working mothers categorized under two groups: Social Economic Status and Work suspension. For Social Economic Status factors, we find five factors which are monthly income, main breadwinner, number of children at school age, type of housing, and type of work. Almost all mothers include spiritual activities to their routine to cope with stress during this period. About half of our sample have negative impact on their mental health because they are the main breadwinner, and mothers with a smaller number of children at school age have more challenges to cope up. We found that mothers who own a house or work at governmental sector have better outcome of health. After analyzing data related to Work suspension, we found that mothers who have work support have better management for life circumstances, however their health outcomes were negatively affected. In addition, mothers working at education sector have the highest positive impact among other sectors. Our data shows that working mothers’ abilities to follow up with their children decreased. This study recommends that there is need to invest more in working mothers’ research and supportive programs and ensure collaboration globally to address working mothers’ needs and share experiences.展开更多
Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel,the calculations of the finishing rolling impact work in th...Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel,the calculations of the finishing rolling impact work in the alloying non-quenched and tempered steel with the elements of Cr,Ni,Mo,W,Cu,V,Nb and Ti are studied with the covalent electron number nA of the strongest bond in alloying phases,the smallest electron density difference?ρof phase interfaces,and the number of atom statesσ(σ′)which keep the interface electron density continuous.The calculated results show that the finishing rolling impact work of the alloying non-quenched and tempered steel intensely depends on strengthening mechanisms.The solution strengthening,interface strengthening,precipita-tion strengthening of pearlite,and dispersion strengthening will result in the decrease of the finishing rolling impact work;the refinement strengthening,the precipitation strength-ening of V,Nb and Ti inα-Fe-C-V(Nb,Ti),and the residual austenite containing Ni on the boundary ofα-Fe-C-Ni will increase the impact work;and the increments or decrements can be calculated with nA,?ρ,σ(σ′)and weights of alloying elements.The calculation formulas of the finishing rolling impact work in this paper are intergraded with the sug-gested ones of the finishing rolling tensile strength,yield strength,and elongation of the non-quenched and tempered steel.The calculated results agree well with the measured ones.展开更多
Based on the hot-continuous rolling technology,the finishing rolling impact workαk of the non-quenched and tempered Si-Mn steel is theoretically calculated with the covalent electron number nA of the strongest bond i...Based on the hot-continuous rolling technology,the finishing rolling impact workαk of the non-quenched and tempered Si-Mn steel is theoretically calculated with the covalent electron number nA of the strongest bond in alloying phases,and the smallest interface electron density differenceΔρof alloying phase interface and the number of atom statesσwhich keep the interface electron density continuous.Calculations show that the solution strengthening,the precipitation strengthening,and the interface strengthening will result in the decrease of the finishing rolling impact workαk,and the effects of the number of atom statesσwhich keep the interface electron density continuous on the finishing rolling impact workαk are different.Taking the impact work and the number of atom statesσ0 keeping the electron density continuous of the phase interfaceα-Fe/α-Fe-C betweenα-Fe andα-Fe-C as reference values,the impact work of the interface will increase whenσof some interface is larger thanσ0;otherwise,the impact will decrease.Therefore,the finishing rolling impact workαk can be calculated with the impact value of the refinedα-Fe matrix and the influence amounts caused by the solution strengthening,the precipitation strengthening,the interface strengthening,and the number of atom statesσwhich keep the interface electron density continuous.The calculated results agree well with the measured ones.In this paper,the effect of S on the impact work is also discussed.展开更多
This work correlated the detailed work zone location and time data from the Wis LCS system with the five-min inductive loop detector data. One-sample percentile value test and two-sample Kolmogorov-Smirnov(K-S) test w...This work correlated the detailed work zone location and time data from the Wis LCS system with the five-min inductive loop detector data. One-sample percentile value test and two-sample Kolmogorov-Smirnov(K-S) test were applied to compare the speed and flow characteristics between work zone and non-work zone conditions. Furthermore, we analyzed the mobility characteristics of freeway work zones within the urban area of Milwaukee, WI, USA. More than 50% of investigated work zones have experienced speed reduction and 15%-30% is necessary reduced volumes. Speed reduction was more significant within and at the downstream of work zones than at the upstream.展开更多
To further understand the hardening mechanism of austenitic manganese steel under actual working conditions, the work hardening ability was studied and the microstructures of austenitic manganese steel were observed u...To further understand the hardening mechanism of austenitic manganese steel under actual working conditions, the work hardening ability was studied and the microstructures of austenitic manganese steel were observed under different impact energies. The work hardening mechanism was also analyzed. The results show that the best strain hardening effect could be received only when the impact energy reaches or exceeds the critical impact energy. The microstructural observations reveal that dislocations, stacking faults and twins increase with raising impact energy of the tested specimens. The hardening mechanism changes at different hardening degrees. It is mainly dislocation and slip hardening below the critical impact energy, but it changes to the twinning hardening mechanism when the impact energy is above the critical impact energy.展开更多
Compared with H13 steel, the influences of different heat treatment process on the microstructure and properties of the new type of hot working die steel H13MOD were studied. The results show that the complete aus ten...Compared with H13 steel, the influences of different heat treatment process on the microstructure and properties of the new type of hot working die steel H13MOD were studied. The results show that the complete aus tenitizing temperature of H13MOD is around 1030 ℃ and the quenching hardness achieves the maximum value at this temperature. While for H13, the complete austenitizing temperature is above 1100 ℃ and the quenching hardness rise constantly with the quenching temperature increasing. In quenching process, the undissolved MC carbides can prevent the coarsening of grain in both steels. With the rise of quenching temperature, when MC carbides dissolve completely, the grain grows quickly. The hardness and strength of H13MOD at higher tempering temperature （above 570 ℃） are nearly the same as those of H13, but its toughness is higher than that of H13. Mo2C carbide is the main strengthening phase in H13MOD, which is attributed to the higher content of Mo. The quantity of VC eutectic car- bides is reduced because of lower content of V in H13MOD, which plays an important role in enhancing the impact toughness of H13MOD. Under a certain strength condition, H13MOD steel can be used in the environment that higher toughness is required and the service life of die casting mold can be improved.展开更多
文摘Coronavirus is a Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) caused by a novel coronavirus belonging to the family Coronaviridae. The disease was first discovered in December 2019 in Wuhan City, Hubei Province, China. A few months later, the disease spread all over the world and became an epidemic. The infection for most people is mild to moderate but in Vulnerable groups, if they have the infections, they might experience severe COVID-19. Saudi Arabia initiated its response plan early, and all sectors and agencies worked in an integrated way to combat the disease. It has maintained proper communication during the pandemic and ensured community involvement, epidemiologic surveillance, and activation of rapid response teams. The COVID-19 pandemic significantly affected daily lives. Schools and daycares were closed, education was online, traveling stopped, work was suspended, gathering in social activities and practicing religious rituals, like praying or doing Umrah or Hajj, were banded. Changing lifestyles as a response to COVID-19 impacted whole communities with different categories of children, parents, and families. Women usually take the majority of daily responsibilities. The sudden change in lifestyle during COVID-19 put pressure on mothers, especially those who are working to balance work and family obligations. This study aims to identify the impact of Coronavirus disease 2019 on working mothers in Saudi Arabia. Method: Data of the study was collected through survey posted on social media and analyzed through Excel. It focuses on five aspects: health, lifestyle, social relations, work production and financial status. Our target population was working mothers in Saudi Arabia aged at least 25 years. Results: In this study, all factors affected working mothers categorized under two groups: Social Economic Status and Work suspension. For Social Economic Status factors, we find five factors which are monthly income, main breadwinner, number of children at school age, type of housing, and type of work. Almost all mothers include spiritual activities to their routine to cope with stress during this period. About half of our sample have negative impact on their mental health because they are the main breadwinner, and mothers with a smaller number of children at school age have more challenges to cope up. We found that mothers who own a house or work at governmental sector have better outcome of health. After analyzing data related to Work suspension, we found that mothers who have work support have better management for life circumstances, however their health outcomes were negatively affected. In addition, mothers working at education sector have the highest positive impact among other sectors. Our data shows that working mothers’ abilities to follow up with their children decreased. This study recommends that there is need to invest more in working mothers’ research and supportive programs and ensure collaboration globally to address working mothers’ needs and share experiences.
基金This work was supported by the National Natural Science Foundation of China(Grant No.50471022).
文摘Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel,the calculations of the finishing rolling impact work in the alloying non-quenched and tempered steel with the elements of Cr,Ni,Mo,W,Cu,V,Nb and Ti are studied with the covalent electron number nA of the strongest bond in alloying phases,the smallest electron density difference?ρof phase interfaces,and the number of atom statesσ(σ′)which keep the interface electron density continuous.The calculated results show that the finishing rolling impact work of the alloying non-quenched and tempered steel intensely depends on strengthening mechanisms.The solution strengthening,interface strengthening,precipita-tion strengthening of pearlite,and dispersion strengthening will result in the decrease of the finishing rolling impact work;the refinement strengthening,the precipitation strength-ening of V,Nb and Ti inα-Fe-C-V(Nb,Ti),and the residual austenite containing Ni on the boundary ofα-Fe-C-Ni will increase the impact work;and the increments or decrements can be calculated with nA,?ρ,σ(σ′)and weights of alloying elements.The calculation formulas of the finishing rolling impact work in this paper are intergraded with the sug-gested ones of the finishing rolling tensile strength,yield strength,and elongation of the non-quenched and tempered steel.The calculated results agree well with the measured ones.
基金This work was supported by the National Natural Science Foundation of China(Grant No.50471022).
文摘Based on the hot-continuous rolling technology,the finishing rolling impact workαk of the non-quenched and tempered Si-Mn steel is theoretically calculated with the covalent electron number nA of the strongest bond in alloying phases,and the smallest interface electron density differenceΔρof alloying phase interface and the number of atom statesσwhich keep the interface electron density continuous.Calculations show that the solution strengthening,the precipitation strengthening,and the interface strengthening will result in the decrease of the finishing rolling impact workαk,and the effects of the number of atom statesσwhich keep the interface electron density continuous on the finishing rolling impact workαk are different.Taking the impact work and the number of atom statesσ0 keeping the electron density continuous of the phase interfaceα-Fe/α-Fe-C betweenα-Fe andα-Fe-C as reference values,the impact work of the interface will increase whenσof some interface is larger thanσ0;otherwise,the impact will decrease.Therefore,the finishing rolling impact workαk can be calculated with the impact value of the refinedα-Fe matrix and the influence amounts caused by the solution strengthening,the precipitation strengthening,the interface strengthening,and the number of atom statesσwhich keep the interface electron density continuous.The calculated results agree well with the measured ones.In this paper,the effect of S on the impact work is also discussed.
基金Project(61620106002)supported by the National Natural Science Foundation of ChinaProject(2016YFB0100906)supported by the National Key R&D Program in China+1 种基金Project(2015364X16030)supported by the Information Technology Research Project of Ministry of Transport of ChinaProject(2242015K42132)supported by the Fundamental Sciences of Southeast University,China
文摘This work correlated the detailed work zone location and time data from the Wis LCS system with the five-min inductive loop detector data. One-sample percentile value test and two-sample Kolmogorov-Smirnov(K-S) test were applied to compare the speed and flow characteristics between work zone and non-work zone conditions. Furthermore, we analyzed the mobility characteristics of freeway work zones within the urban area of Milwaukee, WI, USA. More than 50% of investigated work zones have experienced speed reduction and 15%-30% is necessary reduced volumes. Speed reduction was more significant within and at the downstream of work zones than at the upstream.
基金supported by the Special Foundation for Introducing and Selecting Talent in Hefei University of Technology, China (No. 2004000197)
文摘To further understand the hardening mechanism of austenitic manganese steel under actual working conditions, the work hardening ability was studied and the microstructures of austenitic manganese steel were observed under different impact energies. The work hardening mechanism was also analyzed. The results show that the best strain hardening effect could be received only when the impact energy reaches or exceeds the critical impact energy. The microstructural observations reveal that dislocations, stacking faults and twins increase with raising impact energy of the tested specimens. The hardening mechanism changes at different hardening degrees. It is mainly dislocation and slip hardening below the critical impact energy, but it changes to the twinning hardening mechanism when the impact energy is above the critical impact energy.
文摘Compared with H13 steel, the influences of different heat treatment process on the microstructure and properties of the new type of hot working die steel H13MOD were studied. The results show that the complete aus tenitizing temperature of H13MOD is around 1030 ℃ and the quenching hardness achieves the maximum value at this temperature. While for H13, the complete austenitizing temperature is above 1100 ℃ and the quenching hardness rise constantly with the quenching temperature increasing. In quenching process, the undissolved MC carbides can prevent the coarsening of grain in both steels. With the rise of quenching temperature, when MC carbides dissolve completely, the grain grows quickly. The hardness and strength of H13MOD at higher tempering temperature （above 570 ℃） are nearly the same as those of H13, but its toughness is higher than that of H13. Mo2C carbide is the main strengthening phase in H13MOD, which is attributed to the higher content of Mo. The quantity of VC eutectic car- bides is reduced because of lower content of V in H13MOD, which plays an important role in enhancing the impact toughness of H13MOD. Under a certain strength condition, H13MOD steel can be used in the environment that higher toughness is required and the service life of die casting mold can be improved.
