A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks de...A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone(HAZ). Friction stir processing(FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304 L stainless steel. A numerical simulation of the FSP process in 304 L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach,where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%.展开更多
Aims:To determine whether day and time of admission influences the practice patterns of the admitting general surgeon and subsequent outcomes for patients diagnosed with small bowel obstruction.Methods:A retrospective...Aims:To determine whether day and time of admission influences the practice patterns of the admitting general surgeon and subsequent outcomes for patients diagnosed with small bowel obstruction.Methods:A retrospective database review was carried out,covering patients admitted with the presumed diagnosis of partial small bowel obstruction from 2004–2011.Results:A total of 404 patients met the inclusion criteria.One hundred and thirty-nine were admitted during the day,93 at night and 172 on the weekend.Overall 30.2%of the patients were managed operatively with no significant difference between the groups(P=0.89);however,of patients taken to the operating room,patients admitted during the day received operative intervention over 24 hours earlier than those admitted at a weekend,0.79 days vs 1.90 days,respectively(P=0.05).Overall mortality was low at 1.7%,with no difference noted between the groups(P=0.35).Likewise there was no difference in morbidity rates between the three groups(P=0.90).Conclusions:Despite a faster time to operative intervention in those patients admitted during the day,our study revealed that time of admission does not appear to correlate to patient outcome or mortality.展开更多
We demonstrate digital plasmonic holography for direct in-plane imaging with propagating surface-plasmon waves.Imaging with surface plasmons suffers from the lack of simple in-plane lenses and mirrors.Lens-less digita...We demonstrate digital plasmonic holography for direct in-plane imaging with propagating surface-plasmon waves.Imaging with surface plasmons suffers from the lack of simple in-plane lenses and mirrors.Lens-less digital holography techniques,however,rely on digitally decoding an interference pattern between a reference wave and an object wave.With far-field diffractive optics,this decoding scheme provides a full recording,i.e.,a hologram,of the amplitude and phase of the object wave,giving three-dimensional information from a two-dimensional recording.For plasmonics,only a one-dimensional recording is needed,and both the phase and amplitude of the propagating plasmons can be extracted for high-resolution in-plane imaging.Here,we demonstrate lens-less,point-source digital plasmonic holography using two methods to record the plasmonic holograms:a dual-probe near-field scanning optical microscope and lithographically defined circular fluorescent screens.The point-source geometry gives in-plane magnification,allowing for high-resolution imaging with relatively lower-resolution microscope objectives.These results pave the way for a new form of in-plane plasmonic imaging,gathering the full complex wave,without the need for plasmonic mirrors or lenses.展开更多
基金supported by the National Science Foundation grant CMMI-1405508
文摘A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone(HAZ). Friction stir processing(FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304 L stainless steel. A numerical simulation of the FSP process in 304 L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach,where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%.
文摘Aims:To determine whether day and time of admission influences the practice patterns of the admitting general surgeon and subsequent outcomes for patients diagnosed with small bowel obstruction.Methods:A retrospective database review was carried out,covering patients admitted with the presumed diagnosis of partial small bowel obstruction from 2004–2011.Results:A total of 404 patients met the inclusion criteria.One hundred and thirty-nine were admitted during the day,93 at night and 172 on the weekend.Overall 30.2%of the patients were managed operatively with no significant difference between the groups(P=0.89);however,of patients taken to the operating room,patients admitted during the day received operative intervention over 24 hours earlier than those admitted at a weekend,0.79 days vs 1.90 days,respectively(P=0.05).Overall mortality was low at 1.7%,with no difference noted between the groups(P=0.35).Likewise there was no difference in morbidity rates between the three groups(P=0.90).Conclusions:Despite a faster time to operative intervention in those patients admitted during the day,our study revealed that time of admission does not appear to correlate to patient outcome or mortality.
基金supported by the National Science Foundation through CAREER grant#1552642funds from the NSERC Discovery Grant program and from the Canada Foundation for Innovation(CFI)through the Prometheus project.
文摘We demonstrate digital plasmonic holography for direct in-plane imaging with propagating surface-plasmon waves.Imaging with surface plasmons suffers from the lack of simple in-plane lenses and mirrors.Lens-less digital holography techniques,however,rely on digitally decoding an interference pattern between a reference wave and an object wave.With far-field diffractive optics,this decoding scheme provides a full recording,i.e.,a hologram,of the amplitude and phase of the object wave,giving three-dimensional information from a two-dimensional recording.For plasmonics,only a one-dimensional recording is needed,and both the phase and amplitude of the propagating plasmons can be extracted for high-resolution in-plane imaging.Here,we demonstrate lens-less,point-source digital plasmonic holography using two methods to record the plasmonic holograms:a dual-probe near-field scanning optical microscope and lithographically defined circular fluorescent screens.The point-source geometry gives in-plane magnification,allowing for high-resolution imaging with relatively lower-resolution microscope objectives.These results pave the way for a new form of in-plane plasmonic imaging,gathering the full complex wave,without the need for plasmonic mirrors or lenses.
