Formulation of an alternate concrete mix for concrete filled GFRG panels

Nithya Nandan,R. Renjith 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.2

Glass fiber reinforced gypsum panels (GFRG) are hollow panels made from modified gypsum plaster and reinforced with chopped glass fibers. The hollow cores of panels can be filled with in-situ concrete/reinforced concrete or insulation material to increase the structural strength or the thermal insulation, respectively. GFRG panels are unfilled when used as partition walls. As load bearing walls, the panels are filled with M 20 grade concrete (reinforced concrete filling) in order to resist the gravity and lateral loads. The study was conducted in two stages: First stage involves formulation of the alternate light weight mix by conducting experimental investigations to obtain the optimum combination of phosphogypsum and shredded thermocol. In the second stage the alternate mixes are filled in GFRG panels and experimental investigations are conducted to compare the performance against panels filled with conventional M 20 mix.

Surgical Management of Pyogenic Discitis of Lumbar Region

Pramod Devkota,Krishnakumar R,Renjith Kumar J 대한척추외과학회 2014 Asian Spine Journal Vol.8 No.2

Study Design: Retrospective review of patients who had pyogenic discitis and were managed surgically. Purpose: To analyze the bacteriology, pathology, management and outcome of pyogenic discitis of the lumbar region treated surgically. Overview of Literature: Surgical management of pyogenic discitis is still an infrequently used modality of treatment. Methods: A total of 42 patients comprised of 33 males and 9 females who had pyogenic discitis with a mean age of 51.61 years (range, 16−75 years) were included in this study. All the cases were confirmed as having pyogenic discitis by pus culture report and histopathological examination. The mean follow-up period was 41.9 months. Results: Debridement and posterior lumbar interbody fusion with autologous iliac bone graft was done in all cases. Thirteen (30.95%) patients had other medical co-morbidities. Five cases had a previous operation of the spine, and three cases had a history of vertebral fracture. Three patients were operated for gynaecological problems, and four cases had a history of urological surgery. L4−5 level was the most frequent site of pyogenic discitis. The most common bacterium isolated was Staphylococcus aureus (S. aureus). Radiologically good fusion was seen in the majority of patients. Conclusions: Pyogenic discitis should be suspected in people having pain and local tenderness in the spinal region with a rise in inflammatory parameters in blood. The most common bacterium was S. aureus, but there were still a greater number of patients infected with other types of bacteria. Therefore, antibiotics therapy should be started only after isolating the bacteria and making the culture sensitivity report.

Temperature profile and visible flame length of blended pool fires at quiescent air conditions

Sivi Varghese,V. R. Renjith 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

Alcohol-derived biofuels are used as an alternative fuel source instead of petroleum-based fuels. There is a need to understand the fire behavior of these blended alcohol biofuels. Twelve laboratory-scale pool fire experimental tests were conducted at quiescent ambient air on n-propanol, diesel, and mixtures to understand the burning characteristics, like burning rate, flame temperature, and flame height. The burning rate of pure and blended fuels was estimated by two methods and compared. Visual images of fire were analyzed, and it was found that the maximum visible flame height of all fuels is nearly three-times the pool diameter. Centerline flame temperature is highest for n-propanol pool fires compared with diesel and its blends. A dimensionless temperature parameter φ makes a linear relationship with dimensionless vertical height for pure and binary mixtures. These combustion characteristics of blended fuel pool fire help ensure the safety of blended fuel handling, transportation, and storage.

Burning behavior and thermal hazards of binary blended n-propanol-diesel pool fires

Sivi Varghese,V. R. Renjith 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

The consumption of alternative fuels accelerated in recent years because of the depletion of petroleum fuel sources, and, nowadays, the blended fuel demand is increasing worldwide. Blended fuel structure and burning characteristics are significantly different from pure fuels. The combustion behavior of pool fire of n-propanol, diesel, and their blends was experimentally studied under quiescent ambient air conditions. The fuels were burned in a circular pan of three sizes (D = 0.20, 0.10, and 0.05 m) to explore the burning properties. Blends of diesel with n-propanol were tested with an n-propanol concentration of 10 and 30 % by volume. The mass burning rate (MBR), fuel temperature, and total heat flux from flames were recorded. The combustion parameters of diesel, n-propanol, and blends with different pans were comparable. The propanol fraction enhances the burning rate of diesel, and soot formation is less visible in blended fuels. The average MBR recorded for pure propanol in 0.20 m pan diameter is 0.01548 kg/m 2 .s. The mean fuel temperature difference between thermocouples in diesel is 40 °C, and n-propanol is 20 °C, and for P10, the temperature difference is closer to the diesel. Thermal heat flux is estimated by using a low-cost thin-film heat flux sensor. The total heat flux profile of 0.20 m diameter P10 and P30 blends develops a V-shaped curve between the burning time range of 300 to 650 seconds and 400 to 750 seconds. These characteristics of pool fire combustion aid in the safe storage and handling of blended fuel.

Does Sarcopenia Increase the Risk for Fresh Vertebral Fragility Fractures?: A Case-Control Study

Ashish Anand,Ajoy Prasad Shetty,K. R. Renjith,Sri Vijay Anand K. S.,Rishi Mugesh Kanna,Shanmuganathan Rajasekaran 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.1

Study Design: Case-control study. Purpose: Sarcopenia is an age associated condition characterized by decrease in muscle mass, strength, and physical performance. We aimed to investigate whether sarcopenia increased the risk of vertebral fragility fractures among the elderly. Overview of Literature: Initial reports on sarcopenia suggest its contribution to the development of vertebral fragility fractures. However, recent studies showed contradictory findings. Methods: Fifty-one consecutive patients with vertebral fragility fractures and matched controls without fractures were evaluated for sarcopenia, T-score, body mass index, and presence of preexisting vertebral fractures. Sarcopenia was diagnosed as total psoas cross-sectional area (TPA) 2 standard deviations below normative value from normal young adults and decreased handgrip strength (26 kg for men and 18 kg for women). Univariate and multivariate analyses were performed using the fresh fracture occurrence as the dependent variable. Results: Sarcopenia was confirmed in 29.4% and 7.8% of cases and controls (p=0.005), respectively; 56.8% and 13.7% of cases and controls had previous vertebral fractures. Sarcopenia prevalence was greater among those with previous fractures (38% vs. 7.6%; odds ratio, 7.76; p<0.001). TPA was lower among the cases (1,278 mm2 vs. 1,569 mm2, p=0.001) and those with previous fractures (1,168 mm2 vs. 1,563 mm2, p<0.001). Handgrip strength was greater among those without previous fractures (19.6 kg vs. 16.3 kg, p=0.05). In multivariate analysis, sarcopenia was not identified as a significant predictor of fresh fractures whereas previous fractures and lower T-score were found to be significant. Conclusions: Sarcopenia is not an independent risk factor for fresh vertebral fragility fractures in the elderly.