In the continuous casting production of medium carbon steel (whose mass fraction of carbon is 0.09 % to 0.16 %) and high strength low alloy steel (whose mass fraction of Mn is 0.90 % to 1.40 %), flecks occurring the m...In the continuous casting production of medium carbon steel (whose mass fraction of carbon is 0.09 % to 0.16 %) and high strength low alloy steel (whose mass fraction of Mn is 0.90 % to 1.40 %), flecks occurring the most often are usually longitudinal and star cracks. In additional to the employment of a galvanized plate mould, two kinds of fluxes with special properties were studied and used to harmonize the conflicts between the function of heat transfer and lubrication. An industrial application revealed that the crystallizing temperature (Tc) and crystal ratio (R) of fluxes have a crucible effect on impeding the occurrence of above defects on a slab surface. In the case of slab section (180 to 240) mm(1000 to 1400) mm and casting speed Vc of (0.7 to 1.2) m/min, the optimized parameters of fluxes are Tc of (1170 to 1190) ℃, R of 80 % to 95 % for medium carbon steel, and Tc of (1100 to 1150) ℃, plus R of 40 % to 60 % for high strength low alloy steel.展开更多
In the optimization of the process of steel valve plate grinding, it is necessary to take into consideration different processing parameters. This paper is going to describe the production of a steel valve plate with ...In the optimization of the process of steel valve plate grinding, it is necessary to take into consideration different processing parameters. This paper is going to describe the production of a steel valve plate with the focus on flat-grinding. It is also going to present the method of choosing grinding wheels and parameters, as well as their impact on the processing quality parameters （roughness, surface flatness and seat width）. The optimization of the grinding process ensures acceptable quality of the final product applying the smallest possible changes in parameters at non-uniform quality levels of the tools. Here we have to make sure that the machining process is acceptable in terms of processing cost as weIl. We are going to use the G-factor as the efficiency indicator for different tools.展开更多
Objective：To evaluate functional outcome and complications of open reduction and internal fixation with proximal humeral internal locking system （PHILOS） plate for proximal humerus fractures.Methods：We reviewed 51...Objective：To evaluate functional outcome and complications of open reduction and internal fixation with proximal humeral internal locking system （PHILOS） plate for proximal humerus fractures.Methods：We reviewed 51 patients who underwent open reduction and internal fixation with PHILOS plate between the years 2007 to 2012.There were 35 men and 16 women with a mean age of 38 years （range 24-68）.There were 41 patients in the age group of ＜60 years and 10 patients in the age group of ＞60 years.According to Neer classification system,8,15 and 23 patients had 2-part,3-part,and 4-part fractures,respectively and 5 patients had 4-part fracture dislocation.All surgeries were carried out at our tertiary care trauma centre.Functional evaluation of the shoulder at final follow-up was done using Constant-Murley score.Results：The mean follow-up period was 30 months （range 12-44 months）.Two patients were lost to followup.Of the remaining 49 patients,all fractures were united clinically and radiologically.The mean time for radiological union was 12 weeks （range 8-20 weeks）.At the final follow-up the mean Constant-Murley score was 79 （range 50-100）.The results were excellent in 25 patients,good in 13 patients,fair in 6 patients and poor in 5 patients.During the follow-up,four cases of varus malunion,one case of subacromial impingement,one case of deep infection,one case of intraarticular screw penetration and one case of failure of fixation were noted.No cases of avascular necrosis,hardware failure,locking screw loosening or nonunion were noted.Conclusion：PHILOS provides stable fixation in proximal humerus fractures.To prevent potential complications like avascular necrosis,meticulous surgical dissection to preserve vascularity of humeral head is necessary.展开更多
Objective：Debate continues regarding the management of calcaneal fractures,between open reduction and internal fixation and closed treatment.Hence we aim at evaluating the radiological and functional outcomes of open...Objective：Debate continues regarding the management of calcaneal fractures,between open reduction and internal fixation and closed treatment.Hence we aim at evaluating the radiological and functional outcomes of open reduction and internal fixation in displaced joint depression type of calcaneal fractures fixed with locking calcaneal plate.Methods：In this series,28 patients （26 unilateral and 2 bilateral） with joint depression type of calcaneal fractures as per Essex-Lopresti classification system were operated on with locking calcaneal plate within 3 weeks of injury.Patients were evaluated in terms of associated injuries and X-rays of anteroposterior,lateral and axial views of the calcaneum.CT scan was done to assess the amount ofcomminution and articular depression.Patients were followed up clinically and radiologically at least for 1 year.Radiological assessment was done by Bohler＇s angle and Gissane＇s angle along with measurement ofcalcaneal height and width.Functional outcome was assessed using the American Orthopaedics Foot and Ankle Society （AOFAS） scale.Results：At average follow-up of 14.5 months,average AOFAS score was 86.3 （range 66 to 97）,with 86% having excellent to good results and 2 （7.7%） and 1 （3.7%） having fair and poor results respectively.All patients had stable ankle joint with all having dorsiflexion and plantar flexion more than 30°.Average subtalar range of motion was 17°.The mean Bohler＇s angle,mean Gissane＇s angle,calcaneal height and width were 25.47°,121.3°,4.32 cm and 3.81cm respectively at final follow-up.Three patients had flap necrosis at incision site and one had superficial and deep infection.Subtalar arthritis was seen in 5 patients,whereas sural nerve hypoaesthesia in 1 patient.None of the patients had compartment syndrome,heel pad problems,peroneal tendinitis,reflex sympathetic dystropy or implant failure.Conclusion：Open reduction and internal fixation with locking calcaneal plate gives sound functional outcome,i.e.restoring anatomically reconstruction of height,width,Bohler＇s and Gissiane＇s angles of the calcaneum,and allowing early mobilization.展开更多
文摘In the continuous casting production of medium carbon steel (whose mass fraction of carbon is 0.09 % to 0.16 %) and high strength low alloy steel (whose mass fraction of Mn is 0.90 % to 1.40 %), flecks occurring the most often are usually longitudinal and star cracks. In additional to the employment of a galvanized plate mould, two kinds of fluxes with special properties were studied and used to harmonize the conflicts between the function of heat transfer and lubrication. An industrial application revealed that the crystallizing temperature (Tc) and crystal ratio (R) of fluxes have a crucible effect on impeding the occurrence of above defects on a slab surface. In the case of slab section (180 to 240) mm(1000 to 1400) mm and casting speed Vc of (0.7 to 1.2) m/min, the optimized parameters of fluxes are Tc of (1170 to 1190) ℃, R of 80 % to 95 % for medium carbon steel, and Tc of (1100 to 1150) ℃, plus R of 40 % to 60 % for high strength low alloy steel.
文摘In the optimization of the process of steel valve plate grinding, it is necessary to take into consideration different processing parameters. This paper is going to describe the production of a steel valve plate with the focus on flat-grinding. It is also going to present the method of choosing grinding wheels and parameters, as well as their impact on the processing quality parameters （roughness, surface flatness and seat width）. The optimization of the grinding process ensures acceptable quality of the final product applying the smallest possible changes in parameters at non-uniform quality levels of the tools. Here we have to make sure that the machining process is acceptable in terms of processing cost as weIl. We are going to use the G-factor as the efficiency indicator for different tools.
文摘Objective：To evaluate functional outcome and complications of open reduction and internal fixation with proximal humeral internal locking system （PHILOS） plate for proximal humerus fractures.Methods：We reviewed 51 patients who underwent open reduction and internal fixation with PHILOS plate between the years 2007 to 2012.There were 35 men and 16 women with a mean age of 38 years （range 24-68）.There were 41 patients in the age group of ＜60 years and 10 patients in the age group of ＞60 years.According to Neer classification system,8,15 and 23 patients had 2-part,3-part,and 4-part fractures,respectively and 5 patients had 4-part fracture dislocation.All surgeries were carried out at our tertiary care trauma centre.Functional evaluation of the shoulder at final follow-up was done using Constant-Murley score.Results：The mean follow-up period was 30 months （range 12-44 months）.Two patients were lost to followup.Of the remaining 49 patients,all fractures were united clinically and radiologically.The mean time for radiological union was 12 weeks （range 8-20 weeks）.At the final follow-up the mean Constant-Murley score was 79 （range 50-100）.The results were excellent in 25 patients,good in 13 patients,fair in 6 patients and poor in 5 patients.During the follow-up,four cases of varus malunion,one case of subacromial impingement,one case of deep infection,one case of intraarticular screw penetration and one case of failure of fixation were noted.No cases of avascular necrosis,hardware failure,locking screw loosening or nonunion were noted.Conclusion：PHILOS provides stable fixation in proximal humerus fractures.To prevent potential complications like avascular necrosis,meticulous surgical dissection to preserve vascularity of humeral head is necessary.
文摘Objective：Debate continues regarding the management of calcaneal fractures,between open reduction and internal fixation and closed treatment.Hence we aim at evaluating the radiological and functional outcomes of open reduction and internal fixation in displaced joint depression type of calcaneal fractures fixed with locking calcaneal plate.Methods：In this series,28 patients （26 unilateral and 2 bilateral） with joint depression type of calcaneal fractures as per Essex-Lopresti classification system were operated on with locking calcaneal plate within 3 weeks of injury.Patients were evaluated in terms of associated injuries and X-rays of anteroposterior,lateral and axial views of the calcaneum.CT scan was done to assess the amount ofcomminution and articular depression.Patients were followed up clinically and radiologically at least for 1 year.Radiological assessment was done by Bohler＇s angle and Gissane＇s angle along with measurement ofcalcaneal height and width.Functional outcome was assessed using the American Orthopaedics Foot and Ankle Society （AOFAS） scale.Results：At average follow-up of 14.5 months,average AOFAS score was 86.3 （range 66 to 97）,with 86% having excellent to good results and 2 （7.7%） and 1 （3.7%） having fair and poor results respectively.All patients had stable ankle joint with all having dorsiflexion and plantar flexion more than 30°.Average subtalar range of motion was 17°.The mean Bohler＇s angle,mean Gissane＇s angle,calcaneal height and width were 25.47°,121.3°,4.32 cm and 3.81cm respectively at final follow-up.Three patients had flap necrosis at incision site and one had superficial and deep infection.Subtalar arthritis was seen in 5 patients,whereas sural nerve hypoaesthesia in 1 patient.None of the patients had compartment syndrome,heel pad problems,peroneal tendinitis,reflex sympathetic dystropy or implant failure.Conclusion：Open reduction and internal fixation with locking calcaneal plate gives sound functional outcome,i.e.restoring anatomically reconstruction of height,width,Bohler＇s and Gissiane＇s angles of the calcaneum,and allowing early mobilization.
