Superplasticity in Aeroengine Titanium Alloy VT-9 and its Modified Compositions

The alloy (Ti-6.5AL-3.3 Mo-1.6Zr-O.3Si) is a Soviet composition designated VT-9. Excellent superplastic characteristics found by us in this alloy prompted us to explore the possibility of use of Si-free VT-9 in sheet form for superplastic forming. An optimum thermomechanical processing produced a microstructure that resulted in an elongation of 1700 per cent at a fairly high deformation rate (2 X 10-3 set-1). Thus, the same aeroengine alloy (VT-9) can be used for superplastically formed airframe parts in the Si-free condition. The present study also shows that for making the forming process commercially viable, deformation temperature could be lowered by temporarily alloying with hydrogen in a particular concentration range (0.1 to 0.2 wt per cent)

Thermodynamic properties of interstitial elements in the refractory metals Semiannual report, 1 Dec. 1967 - 31 May 1968

Thermodynamic behavior of interstitial elements in Mo, W, Nb, and T

Solid-State Diffusion Welding of Wrought AISI 304 Stainless Steel to Nimonic AP-1 Superalloy Powder by Hot Isostatic Pressing Dissimilar materials like stainless steels and powder metallurgy superalloys can be joined by diffusion welding using hot isostat

ABSTRACT. The diffusion welding characteristics of wrought AISI 304 stainless steel to a superalloy powder Nimonic AP-1 were examined in this study. After encapsulation, evacuation and degassing, the welds were hot isostatically pressed (HIPed) in two different cycles, i.e., 1200°C (2192°F)/3 h/147 MPa and 1270°C (2318°F)/3 h/121 MPa. A variation in surface condition of stainless steel was also studied for its influence on properties of the joints. These diffusionwelded joints were characterized for diffusion of alloying elements, microstructural features and tensile properties. Most specimens showed good weld strength for both the hot isostatic pressing (HIP) cycles, except specimens with sand blasted surfaces, which gave negligible ductility because of the presence of sand particles embedded on the surface. In general, the tensile properties of the diffusion welded specimens were limited by the mechanical properties of stainless steel and not the joint interface. The microstructural examination of a HIP welded joint showed a thin weld zone of 30-40 ~m. While the stainless steel region of the welded specimen showed a relatively clean structure, the Nimonic AP-1 region showed precipitation of dark particles near the interface extending over 20-60 pm. Electron microprobe analysis of the diffusion welded zone revealed enrichment of titanium-rich particles along prior particle boundaries (PPBs) near the interface. Electron microprobe analysis further revealed extensive diffusion of Ni, Co and AI elements into stainless steel and that of Fe into Nimonic AP-1 superalloy indicating complex composition of the weld interlayer. M. C. SOMANI and N. C. BIRLA, Scientists, are with Defence Metallurgical Research Laboratory, Hyderabad, India, and A. TEKIN is with th

Caecal metastasis from breast cancer presenting as intestinal obstruction

<p>Abstract</p> <p>Background</p> <p>Gastrointestinal metastsasis from the breast cancer are rare. We report a patient who presented with intestinal obstruction due to solitary caecal metastasis from infiltrating ductal carcinoma of breast. We also review the available literature briefly.</p> <p>Case presentation</p> <p>A 72 year old lady with past history of breast cancer presented with intestinal obstruction due to a caecal mass. She underwent an emergency right hemicolectomy. The histological examination of the right hemicolectomy specimen revealed an adenocarcinoma in caecum staining positive for Cytokeratin 7 and Carcinoembryonic antigen and negative for Cytokeratin 20, CDX2 and Estrogen receptor. Eight out of 11 mesenteric nodes showed tumour deposits. A histological diagnosis of metastatic breast carcinoma was given.</p> <p>Conclusion</p> <p>To the best of our knowledge, this is the first case report of solitary metastasis to caecum from infiltrating ductal carcinoma of breast. Awareness of this possibility will aid in appropriate management of such patients.</p

Validation of the care transition measure in multi-ethnic South-East Asia in Singapore

10.1186/1472-6963-12-256BMC Health Services Research121

Bioreactors as engineering support to treat cardiac muscle and vascular disease

Cardiovascular disease is the leading cause of morbidity and mortality in the Western World. The inability of fully differentiated, load-bearing cardiovascular tissues to in vivo regenerate and the limitations of the current treatment therapies greatly motivate the efforts of cardiovascular tissue engineering to become an effective clinical strategy for injured heart and vessels. For the effective production of organized and functional cardiovascular engineered constructs in vitro, a suitable dynamic environment is essential, and can be achieved and maintained within bioreactors. Bioreactors are technological devices that, while monitoring and controlling the culture environment and stimulating the construct, attempt to mimic the physiological milieu. In this study, a review of the current state of the art of bioreactor solutions for cardiovascular tissue engineering is presented, with emphasis on bioreactors and biophysical stimuli adopted for investigating the mechanisms influencing cardiovascular tissue development, and for eventually generating suitable cardiovascular tissue replacements

Postoperative outcomes in oesophagectomy with trainee involvement

BACKGROUND: The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting. METHODS: Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups. RESULTS: Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005). CONCLUSION: Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery