Effect of Gyroscopic Couple on Aircraft Landing Gear Shimmy

This article presents the effect of gyroscopic couples on the shimmy response of landing gear. The gyroscopic effect between the rotational motions of the aircraft’s longitudinal and vertical axes may be one of the causes of shimmy. The vertical load acting on the wheel axle plays a significant role in a tire’s dynamic characteristics, which may influence shimmy oscillation. So, vertical dynamics also need to be considered for shimmy analysis along with lateral and torsional modes. Suitable mathematical models are required to study the system’s shimmy oscillation and stability nature. The mathematical model was developed by introducing a gyroscopic couple with 5 degrees of freedom (DOF). A numeric analysis was made to investigate the influence of gyroscopic couples on the landing gear model. The simulation results of the model with and without gyroscopic couple are compared and the effect of each parameter on shimmy is studied

Compare the efficacy of palonosetron over ondansetron in prevention of postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy under general anesthesia.

INTRODUCTION: The post operative nausea and vomiting is one of the common complications following anaesthesia. The incidence of post operative nausea and vomiting is more following general anaesthesia than regional anaesthesia. The patients undergoing laparoscopic surgeries are more prone for developing post operative nausea and vomiting. Hence we evaluated the efficacy of the effectiveness of intravenous Palonosetron 75mcg with intravenous Ondansetron 4mg as single pre induction dose in laparoscopic cholecystectomy in preventing PONV following general anaesthesia. METHODOLOGY: After obtaining Institutional Human Ethics Committee clearance the study was carried out in PSGIMS&R during July 2014 – May 2015. A total of 100 patients who were posted for laparoscopic cholecystectomy belonging to ASA Class I & II were included in the study. These patients were randomized into 2 groups of 50 each by computer generated randomized numbers. The patients belonging to Group – A received Inj. Ondansetron 4mg just before induction of anaesthesia and patients belonging to Group – B received Inj. Palonosetron 75mcg just before induction of anaesthesia. All patients were followed for 24 hours post operatively. The incidences of nausea, retching and vomiting were observed postoperatively during 2 hrs, 6 hrs and 24 hrs post procedure interval period. RESULTS: In our study, the incidence of nausea, retching, vomiting at 24 hrs post procedure in Ondansetron group are 38%, 16% and 28% respectively. The incidence of nausea and vomiting at 24 hrs post procedure in Palonosetron group are 12% and 4%. The incidence of nausea and vomiting are more at period between 6hrs and 24 hrs post procedure. The incidence of nausea was 38 percent in Ondansetron group and 12 percent in Palonosetron group [p value 0.003]. The incidence of vomiting was 28 percent in Ondansetron group and 4 percent in Palonosetron group [p value 0.001]. Need for rescue medication was also high in Ondansetron group when compared to Palonosetron group [p value 0.001]. The complete responders in Ondansetron group are 62% and in Palonosetron group are 88% [p value 0.003]. There were no adverse events reported throughout the study in both the groups. CONCLUSION: Based on our study, it is observed that Palonosetron a second generation 5HT3 receptor antagonist has prolonged duration of action and has decreased the incidence of post operative nausea and vomiting significantly when compared to Ondansetron, providing patients with lesser episodes of PONV in patients undergoing laparoscopic cholecystectomy under general anesthesia

Shimmy analysis of light weight aircraft nose wheel landing gear

This paper presents mathematical modeling and analysis of shimmy oscillations for a light weight airplane single wheel nose landing gear. Shimmy is a self-excited oscillation which occurs usually on the nose wheel landing gear assembly during ground maneuvers which is governed by the dynamic characteristics of the landing gear and tires. Shimmy oscillation may lead to reduce the fatigue life of the landing gear and fuselage structure. So, the study of dynamic response and stability boundaries of landing gear plays crucial role while designing of airplanes. In earlier studies of vehicle shimmy only 3 degrees of freedom (DOF) considered such as torsional mode, lateral bending mode and tire lateral deformation. In this work along with above mentioned DOF, two more additional DOF introduced such as axial vibration of strut and tire in order to include the effect of vertical dynamics on shimmy model. Gyroscopic coupling effect also included in the model to study its influence on shimmy. Analysis carried out to determine critical velocity region for occurrence of shimmy and to investigate the effectiveness of ground unevenness on the landing gear system for two different runway conditions such as flat runway and random roughness runway. The results are more helpful to study significant interaction between the different parameters of landing gear and to represent stability boundaries

Your place or mine: transnational education and the locus of control

In transnational education the place – in both an organisational and a geographic sense – in which educational decisions are made impacts on the academics involved and on student learning. The subject of this paper is learning and accreditation that takes place outside a home university through offshore branch campuses. A case study of two Australian Universities with offshore campuses in Sarawak, Malaysia was undertaken. Policies and procedures were reviewed and an empirical study of the experiences of academics involved was conducted. The study focused on who makes decisions about curriculum content, learning and teaching activities, design and provision of educational resources, and the assessment of student work. Consequences of the organisational relationships for academics involved and for student learning are examined in this paper. On the basis of the study a high degree of local control is recommended, at least for units of study that have operated transnationally several times

Implementing business related projects in Foundation Commerce: Business studies units

Group-based class projects have been used as popular pedagogical tools by many institutions in developing team-work skills among students. The ability to work in teams is a much valued skill sought by many organisations (Shaw, 2004). Studies on the inclusion of business related group projects as assessments at foundation programs level, is scarce. This paper reports on a case study that investigated the perceptions of both students and staff regarding the inclusion of business related group projects in commerce units in a foundation programme. The study looked at students’ learning experiences, knowledge gained, and attitudes towards group-based assessments reflecting the effectiveness and value of including group projects in commerce units. The units which incorporated group based projects include Accounting, Business Management and Economics. In general, students agree that group-based projects facilitate learning new skills or concepts from team members, enhance problem solving skills, and promote team work skills. The teaching staff’s perceptions on the inclusion of the projects were encouraging and positive for most units. However, the implementation process of the projects for some units, warrant further investigation in order to enhance and improve the learning experiences of the students

Transapical miniaturized ventricular assist device: Design and initial testing

BackgroundLeft ventricular assist devices are increasingly used to treat patients with advanced and otherwise refractory heart failure as bridge to transplant or destination therapy. We evaluated a new miniaturized left ventricular assist device that requires minimal surgery for implantation, potentially allowing implantation in earlier stage heart failure.MethodsHeartWare (Miami Lakes, Fla) developed transapical miniaturized ventricular assist device. Acute (n = 4), 1-week (n = 2), and 30-day (n = 4) bovine model experiments evaluated hemodynamic efficacy and biocompatibility of the device, which was implanted through small left thoracotomy with single insertion at apex of left ventricle without cardiopulmonary bypass. The device outflow cannula was positioned across the aortic valve. The international normalized ratio was maintained between 2.0 and 2.5 with warfarin. Hemodynamic, echocardiographic, fluoroscopic, hematologic, and blood chemistry measurements were evaluated.ResultsThe device was successfully implanted through the left ventricular apex in all 10 animals. The device was operated at 15,000 ± 1000 rpm (power consumption, 3.5–6.0 W). The device maintained normal end-organ perfusion with no significant hemolysis (0–30 mg/dL). There were no pump failures or device-related complications. At autopsy, no abnormalities were seen in endocardium, aortic valve leaflets, or aortic root. There was no evidence of thromboembolism or abnormalities in any peripheral end organs.ConclusionsWe successfully demonstrated feasibility of a novel intraventricular assist device that can be completely implanted through left ventricular apex. This transapical surgical approach eliminates needs for sternotomy, device pocket, cardiopulmonary bypass, ventricular coring, and construction of an outflow graft anastomosis

10 A noninvasive approach for the early detection of diabetic retinopathy

This chapter introduces one of the most critical problems in ophthalmology, specifically the diagnosis and detection of diabetic retinopathy (DR). Developing a fast, accurate, and reliable method for the early detection of DR is of great clinical importance to prevent blindness in patients. For this reason, various methods for early detection of DR have been investigated and used such as a dilated eye examination, tonometry, fluorescein angiography, optical coherence tomography, and ultrawide-field retinal imaging. With the increased popularity of machine learning, researchers have formulated their own algorithms and methods to detect DR with various rates of success. This chapter overviews past and current diagnostic methods that have been developed for DR. In addition, this chapter addresses new methodologies being developed/researched and some challenges that researchers face in developing fast, accurate, and reliable diagnosis

Cooperation of MICAL-L1, syndapin2, and phosphatidic acid in tubular recycling endosome biogenesis.

Endocytic transport necessitates the generation of membrane tubules and their subsequent fission to transport vesicles for sorting of cargo molecules. The endocytic recycling compartment, an array of tubular and vesicular membranes decorated by the Eps15 homology domain protein, EHD1, is responsible for receptor and lipid recycling to the plasma membrane. It has been proposed that EHD dimers bind and bend membranes, thus generating recycling endosome (RE) tubules. However, recent studies show that molecules interacting with CasL-Like1 (MICAL-L1), a second, recently identified RE tubule marker, recruits EHD1 to preexisting tubules. The mechanisms and events supporting the generation of tubular recycling endosomes were unclear. Here, we propose a mechanism for the biogenesis of RE tubules. We demonstrate that MICAL-L1 and the BAR-domain protein syndapin2 bind to phosphatidic acid, which we identify as a novel lipid component of RE. Our studies demonstrate that direct interactions between these two proteins stabilize their association with membranes, allowing for nucleation of tubules by syndapin2. Indeed, the presence of phosphatidic acid in liposomes enhances the ability of syndapin2 to tubulate membranes in vitro. Overall our results highlight a new role for phosphatidic acid in endocytic recycling and provide new insights into the mechanisms by which tubular REs are generated.journal articleresearch support, n.i.h., extramuralresearch support, non-u.s. gov't2013 Jun2013 04 17importe

Physiological Biomimetic Culture System for Pig and Human Heart Slices

RATIONALE: Preclinical testing of cardiotoxicity and efficacy of novel heart failure therapies faces a major limitation: the lack of an in situ culture system that emulates the complexity of human heart tissue and maintains viability and functionality for a prolonged time. OBJECTIVE: To develop a reliable, easily reproducible, medium-throughput method to culture pig and human heart slices under physiological conditions for a prolonged period of time. METHODS AND RESULTS: Here, we describe a novel, medium-throughput biomimetic culture system that maintains viability and functionality of human and pig heart slices (300 µm thickness) for 6 days in culture. We optimized the medium and culture conditions with continuous electrical stimulation at 1.2 Hz and oxygenation of the medium. Functional viability of these slices over 6 days was confirmed by assessing their calcium homeostasis, twitch force generation, and response to β-adrenergic stimulation. Temporal transcriptome analysis using RNAseq at day 2, 6, and 10 in culture confirmed overall maintenance of normal gene expression for up to 6 days, while over 500 transcripts were differentially regulated after 10 days. Electron microscopy demonstrated intact mitochondria and Z-disc ultra-structures after 6 days in culture under our optimized conditions. This biomimetic culture system was successful in keeping human heart slices completely viable and functionally and structurally intact for 6 days in culture. We also used this system to demonstrate the effects of a novel gene therapy approach in human heart slices. Furthermore, this culture system enabled the assessment of contraction and relaxation kinetics on isolated single myofibrils from heart slices after culture. CONCLUSIONS: We have developed and optimized a reliable medium-throughput culture system for pig and human heart slices as a platform for testing the efficacy of novel heart failure therapeutics and reliable testing of cardiotoxicity in a 3D heart model