Purpose-It is quite universal for high-speed turnouts to be exposed to the wear of the stock rail of the switch rail during the service process.The wear will cause the change of railhead profile and the relative posit...Purpose-It is quite universal for high-speed turnouts to be exposed to the wear of the stock rail of the switch rail during the service process.The wear will cause the change of railhead profile and the relative positions of the switch rail and the stock rail,which will directly affect the wheel-rail contact state and wheel load transition when a train passes the turnout and will further impose serious impacts on the safety and stability of train operation.The purpose of this paper is to provide suggestions for wear management of high-speed turnout.Design/methodology/approach-The actual wear characteristics of switch rails of high-speed turnouts in different guiding directions were studied based on the monitoring results on site;the authorized wear limits for the switch rails of high-speed turnout were studied through derailment risk analysis and switch rail strength analysis.Findings-The results show that:the major factor for the service life of a curved switch rail is the lateral wear.The wear characteristics of the curved switch rail of a facing turnout are significantly different from those of a trailing turnout.To be specific,the lateral wear of the curved switch rail mainly occurs in the narrower section at its front end for a trailing turnout,but in the wider section at its rear end when for a facing turnout.The maximum lateral wear of a dismounted switch rail from a trailing turnout is found on the 15-mm wide section and is 3.9 mm,which does not reach the specified limit of 6 mm.For comparison,the lateral wear of a dismounted switch rail from a facing turnout is found from the 35-mm wide section to the full-width section and is greater than 7.5 mm,which exceeds the specified limit.Based on this,in addition to meeting the requirements of maintenance rules,the allowed wear of switch rails of high-speed turnout shall be so that the dangerous area with a tangent angle of wheel profile smaller than 43.68 will not contact the switch rail when the wheel is lifted by 2 mm.Accordingly,the lateral wear limit at the 5-mm wide section of the curved switch rail shall be reduced from 6 mm(as specified)to 3.5 mm.Originality/value-The work in this paper is of reference significance to the research on the development law of rail wear in high-speed turnout area and the formulation of relevant standards.展开更多
BACKGROUND Gastrointestinal stromal tumors(GISTs)are the most frequent mesenchymal tumors of gastrointestinal tract.The most common sites of metastases are the liver and the peritoneum,whereas breast metastases from G...BACKGROUND Gastrointestinal stromal tumors(GISTs)are the most frequent mesenchymal tumors of gastrointestinal tract.The most common sites of metastases are the liver and the peritoneum,whereas breast metastases from GIST are extremely rare.We present a second case of GIST breast metastasis.CASE SUMMARY We found a case of breast metastasis from rectum GIST.A 55-year-old female patient presented with rectum tumor with multiply liver lesions and metastasis in the right breast.Abdominal-perineal extirpation of rectum was performed,histology and immunohistochemistry study showed GIST,mixed type with CD117 and DOG-1 positive staining.The patient was taking imatinib 400 mg for 22 mo with stable disease.Because of growth of the breast metastasis the treatment was changed twice:The dose of imatinib was doubled with further progression in the breast lesion and then the patient was receiving sunitinib for 26 mo with partial response in the right breast and stable disease in the liver lesions.The breast lesion increased and right breast resection was done–surgery on local progression,the liver metastases were stable.Histology and immunohistochemistry studies revealed GIST metastasis,CD 117 and DOG 1 positive with KIT exon 11 mutation.After surgery the patient resumed imatinib.Until now the patient has been taking imatinib 400 mg for 19 mo without progression,last follow up was in November 2022.CONCLUSION GISTs breast metastases are extremely rare,we described the second case.At the same time second primary tumors have been reported frequently in patients diagnosed with GISTs and breast cancer is one of the most common second primary tumors in patients with GISTs.That is why it is very important to distinguish primary from metastatic breast lesions.Surgery on local progression made it possible to resume less toxic treatment.展开更多
基金supported by the Fund of China Academy of Railway Sciences Corporation Limited (Grant Nos.2022YJ177 and 2022YJ088).
文摘Purpose-It is quite universal for high-speed turnouts to be exposed to the wear of the stock rail of the switch rail during the service process.The wear will cause the change of railhead profile and the relative positions of the switch rail and the stock rail,which will directly affect the wheel-rail contact state and wheel load transition when a train passes the turnout and will further impose serious impacts on the safety and stability of train operation.The purpose of this paper is to provide suggestions for wear management of high-speed turnout.Design/methodology/approach-The actual wear characteristics of switch rails of high-speed turnouts in different guiding directions were studied based on the monitoring results on site;the authorized wear limits for the switch rails of high-speed turnout were studied through derailment risk analysis and switch rail strength analysis.Findings-The results show that:the major factor for the service life of a curved switch rail is the lateral wear.The wear characteristics of the curved switch rail of a facing turnout are significantly different from those of a trailing turnout.To be specific,the lateral wear of the curved switch rail mainly occurs in the narrower section at its front end for a trailing turnout,but in the wider section at its rear end when for a facing turnout.The maximum lateral wear of a dismounted switch rail from a trailing turnout is found on the 15-mm wide section and is 3.9 mm,which does not reach the specified limit of 6 mm.For comparison,the lateral wear of a dismounted switch rail from a facing turnout is found from the 35-mm wide section to the full-width section and is greater than 7.5 mm,which exceeds the specified limit.Based on this,in addition to meeting the requirements of maintenance rules,the allowed wear of switch rails of high-speed turnout shall be so that the dangerous area with a tangent angle of wheel profile smaller than 43.68 will not contact the switch rail when the wheel is lifted by 2 mm.Accordingly,the lateral wear limit at the 5-mm wide section of the curved switch rail shall be reduced from 6 mm(as specified)to 3.5 mm.Originality/value-The work in this paper is of reference significance to the research on the development law of rail wear in high-speed turnout area and the formulation of relevant standards.
文摘BACKGROUND Gastrointestinal stromal tumors(GISTs)are the most frequent mesenchymal tumors of gastrointestinal tract.The most common sites of metastases are the liver and the peritoneum,whereas breast metastases from GIST are extremely rare.We present a second case of GIST breast metastasis.CASE SUMMARY We found a case of breast metastasis from rectum GIST.A 55-year-old female patient presented with rectum tumor with multiply liver lesions and metastasis in the right breast.Abdominal-perineal extirpation of rectum was performed,histology and immunohistochemistry study showed GIST,mixed type with CD117 and DOG-1 positive staining.The patient was taking imatinib 400 mg for 22 mo with stable disease.Because of growth of the breast metastasis the treatment was changed twice:The dose of imatinib was doubled with further progression in the breast lesion and then the patient was receiving sunitinib for 26 mo with partial response in the right breast and stable disease in the liver lesions.The breast lesion increased and right breast resection was done–surgery on local progression,the liver metastases were stable.Histology and immunohistochemistry studies revealed GIST metastasis,CD 117 and DOG 1 positive with KIT exon 11 mutation.After surgery the patient resumed imatinib.Until now the patient has been taking imatinib 400 mg for 19 mo without progression,last follow up was in November 2022.CONCLUSION GISTs breast metastases are extremely rare,we described the second case.At the same time second primary tumors have been reported frequently in patients diagnosed with GISTs and breast cancer is one of the most common second primary tumors in patients with GISTs.That is why it is very important to distinguish primary from metastatic breast lesions.Surgery on local progression made it possible to resume less toxic treatment.
