Determination of load capacity of a nongasketed flange joint under combined internal pressure, axial and bending loading for safe strength and sealing

Performance of a bolted flange joint is characterized mainly due to its ‘strength’ and ‘sealing capability’. A number of analytical and experimental studies have been conducted to study these characteristics only under internal pressure loading. A very limited work is found in literature under combined internal pressure and bending loading. Due to the ignorance of external loads i.e. bending and axial in addition to the internal pressure loading, an optimized performance of the bolted flange joint can not be achieved. The present design codes do not address the effects of combined loading on the structural integrity and sealing ability. To investigate joint strength and sealing capability under combined loading, an extensive comparative experimental and numerical study of a non-gasketed flange joint with two different taper angles on the flange surface and with different load combinations is carried out and overall joint performance and behavior is discussed. Actual joint load capacity is determined under both the design and proof test pressures with maximum additional external loading (axial and bending) that can be applied for safe joint performance

Increased Age, but Not Parity Predisposes to Higher Bacteriuria Burdens Due to Streptococcus Urinary Tract Infection and Influences Bladder Cytokine Responses, Which Develop Independent of Tissue Bacterial Loads

Streptococcus agalactiae causes urinary tract infection (UTI) in pregnant adults, non-pregnant adults, immune-compromised individuals and the elderly. The pathogenesis of S. agalactiae UTI in distinct patient populations is poorly understood. In this study, we used murine models of UTI incorporating young mice, aged and dam mice to show that uropathogenic S. agalactiae causes bacteriuria at significantly higher levels in aged mice compared to young mice and this occurs coincident with equivalent levels of bladder tissue colonisation at 24 h post-infection (p.i.). In addition, aged mice exhibited significantly higher bacteriuria burdens at 48 h compared to young mice, confirming a divergent pattern of bacterial colonization in the urinary tract of aged and young mice. Multiparous mice, in contrast, exhibited significantly lower urinary titres of S. agalactiae compared to age-matched nulliparous mice suggesting that parity enhances the ability of the host to control S. agalactiae bacteriuria. Additionally, we show that both age and parity alter the expression levels of several key regulatory and pro-inflammatory cytokines, which are known to be important the immune response to UTI, including Interleukin (IL)-1β, IL-12(p40), and Monocyte Chemoattractant Protein-1 (MCP-1). Finally, we demonstrate that other cytokines, including IL-17 are induced significantly in the S. agalactiae-infected bladder regardless of age and parity status. Collectively, these findings show that the host environment plays an important role in influencing the severity of S. agalactiae UTI; infection dynamics, particularly in the context of bacteriuria, depend on age and parity, which also affect the nature of innate immune responses to infection