In this study, residual stresses in heat treated specimen were measured by using ESPI (Electronic Speckle-Pattern Interferometry) combined with the hole-drilling method.The specimen, made of SUS 304 austenitic stainle...In this study, residual stresses in heat treated specimen were measured by using ESPI (Electronic Speckle-Pattern Interferometry) combined with the hole-drilling method.The specimen, made of SUS 304 austenitic stainless steel, was quenched and water cooled to room temperature.Numerical simulation using a hybrid FDM/FEM package was also carried out to simulate the heat treatment process.As a result, the thermal stress fields were obtained from both the experiment and the numerical simulation.By comparision of stress fields, results from the experimental method and numerical simulation well agreed to each other, therefore, it is proved that the presented experimental method is applicable and reliable for heat treatment induced residual stress measurement.展开更多
Background: Macular holes are the common cause of visual impairment especially in the elderly and have a variety of etiological factors. The advances in the management of macular holes are encouraging and are now avai...Background: Macular holes are the common cause of visual impairment especially in the elderly and have a variety of etiological factors. The advances in the management of macular holes are encouraging and are now available in developing countries although scarce, where hitherto;patients seek attention outside their country. The need to understand this disease has therefore become pertinent in all retina clinics. Objective: To evaluate the pattern of presentation of macular holes and its management in a retina clinic in South South Nigeria. Methods: A 5 year retrospective, non comparative review of 24 consecutive cases presenting to a retinal clinic was carried out. Relevant information was extracted from the medical records and analyzed. Results: Three hundred and sixty four cases were seen between January 2009 and December 2013. Twenty four cases had macular holes and ten (41.7%) had bilateral presentation with a total of 34 eyes. The incidence of macular holes was 6.6%. The mean age was 46 years (SD ± 13.42) with a female preponderance, 5:1. Idiopathic holes formed the bulk of the cases 14(58.3%);others were trauma 4(16.7%), posterior uveitis 2, (8.3%), chemotherapy 2 (8.3%), Solar retinopathy and retinitis pigmentosa 1 (4.2%). Nineteen (55.9%) of the 34 eyes were visually impaired (BCVA <6/18). Nineteen eyes had full thickness holes (55.9%) requiring surgery, however only 3(12.5%) of these could afford to have surgery with one reoperation. Four patients (16.7%) had complications in form of retinal detachments at presentation. Conclusion: This study has shown that the incidence of macular holes in the developing world is significant and resources to manage these cases are grossly lacking. Specialist training, with government subsidizing costs will alleviate these difficulties and reduce visual loss from macular holes.展开更多
文摘In this study, residual stresses in heat treated specimen were measured by using ESPI (Electronic Speckle-Pattern Interferometry) combined with the hole-drilling method.The specimen, made of SUS 304 austenitic stainless steel, was quenched and water cooled to room temperature.Numerical simulation using a hybrid FDM/FEM package was also carried out to simulate the heat treatment process.As a result, the thermal stress fields were obtained from both the experiment and the numerical simulation.By comparision of stress fields, results from the experimental method and numerical simulation well agreed to each other, therefore, it is proved that the presented experimental method is applicable and reliable for heat treatment induced residual stress measurement.
文摘Background: Macular holes are the common cause of visual impairment especially in the elderly and have a variety of etiological factors. The advances in the management of macular holes are encouraging and are now available in developing countries although scarce, where hitherto;patients seek attention outside their country. The need to understand this disease has therefore become pertinent in all retina clinics. Objective: To evaluate the pattern of presentation of macular holes and its management in a retina clinic in South South Nigeria. Methods: A 5 year retrospective, non comparative review of 24 consecutive cases presenting to a retinal clinic was carried out. Relevant information was extracted from the medical records and analyzed. Results: Three hundred and sixty four cases were seen between January 2009 and December 2013. Twenty four cases had macular holes and ten (41.7%) had bilateral presentation with a total of 34 eyes. The incidence of macular holes was 6.6%. The mean age was 46 years (SD ± 13.42) with a female preponderance, 5:1. Idiopathic holes formed the bulk of the cases 14(58.3%);others were trauma 4(16.7%), posterior uveitis 2, (8.3%), chemotherapy 2 (8.3%), Solar retinopathy and retinitis pigmentosa 1 (4.2%). Nineteen (55.9%) of the 34 eyes were visually impaired (BCVA <6/18). Nineteen eyes had full thickness holes (55.9%) requiring surgery, however only 3(12.5%) of these could afford to have surgery with one reoperation. Four patients (16.7%) had complications in form of retinal detachments at presentation. Conclusion: This study has shown that the incidence of macular holes in the developing world is significant and resources to manage these cases are grossly lacking. Specialist training, with government subsidizing costs will alleviate these difficulties and reduce visual loss from macular holes.
