No abstract

Background and Aims:i-gel® insertion necessitates adequate depth of anaesthesia to prevent laryngospasm, gagging or limb movements. We aimed to compare i-gel® insertion conditions with propofol induction after pre-treatment with dexmedetomidine or fentanyl.Methods:Eighty ASAI/II patients undergoing general anaesthesia were randomised into Groups D (n = 40) and F (n = 40). Group D received 1 μg/kg dexmedetomidine over 10 minutes followed by 5ml of 0.9%normal saline (NS) over 2 minutes. Group F received 10 ml of 0.9%NS over 10 minutes followed by fentanyl 1 μg/kg over 2 minutes. Thirty seconds after study drugs, propofol 2 mg/kg was given. Ninety seconds after propofol, i-gel® was inserted. Overall insertion conditions were assessed by Modified Scheme of Lund and Stovener. Heart-rate (HR) and mean arterial pressure (MAP) were noted at baseline, after study drug, propofol induction and 1,3,5,10 minutes after i-gel® insertion. Respiratory rate and apnoea times were recorded.Results:Insertion conditions were comparable between both groups. Moderately relaxed jaw, coughing and movement was observed in more patients of Group F. Incidence of apnoea was significantly higher (P < 0.0001) in group F (18/40) than group D (3/40).Mean duration of apnoea in group F (284.5 ± 11.19 sec) was significantly higher than group D (217.17 ± 16.48 sec). Percentage drop in MAP from baseline after propofol was more in group F (10.3%) than group D (5.6%). MAP after induction was significantly lower in group F compared to group D (P = 0.002), but similar after i-gel® insertion, 1,3,5 and 10 minutes after insertion. After propofol (P = 0.003) and i-gel® insertion (P < 0.001), HR was significantly lower with dexmedetomidine.Conclusion:Dexmedetomidine and fentanyl provide comparable conditions for i-gel® insertion with propofol.

Honeycomb sandwich panels are investigated for a broad range of areas as protective structures that can withstand blast loading. The advantage of these panels is that they are light in weight when compared to solid metal plates due to the hollow core and have high energy absorption capabilities. Due to their high bending stiffness, honeycomb sandwich panels have found applications in aerospace, automotive, marine, defense, and railway industries. In order to analyze the effect of blast loading on sandwich panels the experiments that need to be conducted are costly as well as time-consuming. Also, while conducting experiments with explosives, human safety is a major concern. Taking the aforementioned parameters into consideration, modeling and simulation of honeycomb sandwich panels is the better alternative. ABAQUS software has been used in this paper to study the behavior of metallic honeycomb sandwich panels (MHSP) with squared, hexagonal, and circular cores when subjected to blast loads of different kilograms of trinitrotoluene (TNT). The obtained simulation results show that circular core has higher blast resistance as compared to hexagonal and square cores. With the aim of optimizing blast protection characteristics of the sandwich model, effect of gel-filling and addition of Aluminium foamto hollow honeycomb core of the sandwich panelswas investigated.The face plate deflection and energy absorption capacity were found to have improved after these additions. Mass evaluation pertaining to reduction in plate deflection versus increase in weight of the sandwich panel after addition of gel and foam was also performed. The influence of strain rate on the deflection of blast-loaded sandwich panels was also studied. It was found that higher strain rates gave favourable results i.e., lower deformation values. Lastly, energy absorption study of all the various configurations of the sandwich panel was performed.