Biological Propulsion Systems for Ships and Underwater Vehicles

Regulations and performance requirements related to technology development on all modes of transport vehicles for reduced pollution and environmental impact have become more stringent. Greening of transport system has been recognized as an important factor concerning global warming and climate change. Thus environment-friendly technical solutions offering a reduction of noxious exhaust gases are in demand. Aquatic animals have good swimming and maneuvering capabilities and these observations have motivated research on fish-like propulsion for marine vehicles. The fish fin movements, used by fish for their locomotion and positioning, are being replicated by researchers as flapping foils to mimic the biological system. Studies show that flapping foil propulsion systems are generally more efficient than a conventional screw propeller, which suffers efficiency losses due to wake. The flapping foil propulsors usually do not cavitate and have less wake velocity variation. These aspects result in the reduction of noise and vibration. The present study will cover an overview of aquatic propulsion systems, numerical simulations of flapping foils and ship model self-propulsion experiments performed using flapping foil system, particle image velocimetry (PIV), and digital fluoroscopy studies conducted on fish locomotion. Studies performed on underwater and surface vehicles fitted with flapping fins will also be presented

Surgery for acromegaly: Indications and goals

Acromegaly is a disease that occurs secondary to high levels of GH, most often from a hormone-secreting pituitary adenoma, with multisystem adverse effects. Diagnosis includes serum GH and IGF-1 levels, and obtaining an MRI pituitary protocol to assess for a functional pituitary adenoma. Attempted gross total resection of the GH-secreting adenoma is the gold standard in treatment for patients with acromegaly for a goal of biochemical remission. Medical and radiation therapies are available when patients do not achieve biochemical cure after surgical therapy

Macrophages sense and kill bacteria through carbon monoxide-dependent inflammasome activation

Microbial clearance by eukaryotes relies on complex and coordinated processes that remain poorly understood. The gasotransmitter carbon monoxide (CO) is generated by the stress-responsive enzyme heme oxygenase-1 (HO-1, encoded by Hmox1), which is highly induced in macrophages in response to bacterial infection. HO-1 deficiency results in inadequate pathogen clearance, exaggerated tissue damage, and increased mortality. Here, we determined that macrophage-generated CO promotes ATP production and release by bacteria, which then activates the Nacht, LRR, and PYD domains-containing protein 3 (NALP3) inflammasome, intensifying bacterial killing. Bacterial killing defects in HO-1-deficient murine macrophages were restored by administration of CO. Moreover, increased CO levels enhanced the bacterial clearance capacity of human macrophages and WT murine macrophages. CO-dependent bacterial clearance required the NALP3 inflammasome, as CO did not increase bacterial killing in macrophages isolated from NALP3-deficient or caspase-1-deficient mice. IL-1β cleavage and secretion were impaired in HO-1-deficient macrophages, and CO-dependent processing of IL-1β required the presence of bacteria-derived ATP. We found that bacteria remained viable to generate and release ATP in response to CO. The ATP then bound to macrophage nucleotide P2 receptors, resulting in activation of the NALP3/IL-1β inflammasome to amplify bacterial phagocytosis by macrophages. Taken together, our results indicate that macrophage-derived CO permits efficient and coordinated regulation of the host innate response to invading microbes.NIH grants: (HL-071797, HL-076167, HL-106227), American Heart Association grants: (10SDG2640091 and NIH R21CA169904-01), Julie Henry Fund, Transplant Center of the BIDMC, FCT grants: (SFRH/BPD/25436/2005, PTDC/BIO/70815/2006, PTDC/BIA-BCM/101311/2008, PTDC/SAU-FCF/100762/2008), the European Community, 6th Framework grant LSH-2005-1.2.5-1 and ERC-2011-AdG, Howard Hughes Medical Institute

Determination of ADAS AEB Car to Car and Car to Pedestrian Scenarios for Autonomous Vehicles

The percentage of ADAS features installed in cars and trucks, which are getting increasingly popular, has significantly increased. Experimental and numerical simulations are necessary to validate ADAS functions and assure passengers' safety. Per Euro NCAP testing standards, numerical studies are carried out on the current ADAS functions. The Lane Keeping Assist System and ADAS features were considered using MATLAB and Simulink software. In the present study, ADAS development and qualification tests are studied concerning vulnerable road users (VRU), such as Car to Car driving and Car to Pedestrian scenarios. Different parameters are used to investigate the impacts of subject/global and ego vehicle conditions such as acceleration, deceleration, perceptual reaction time, gap acceptability, and stop/go choice to avoid collisions. The present methodology evaluates Time-To-Collision (TTC) for different car-to-car and Car-to-pedestrian scenarios at different vehicle velocities. This method of testing autonomous emergency braking (AEB) function for passenger vehicles results in collision mitigation and avoidance and reduces the number of accidents based on human errors. © 2022 IEEE

Absorption & Fluorescence Spectra of p-(Imidazol-l-yl)phenol-Study of Solvent Dependence & Determination of Acidity Constants

513-51

Powering Prediction of an Autonomous Campus Shuttle using CFD

Universities and colleges worldwide are being equipped with campus shuttles due to their large campus size. These generally are 6-To-8-seater vehicles to transport students around the campus. Academic spaces around the world are built as safe places for the academia of the institution. Due to high safety advantages, many universities are considering utilizing autonomous vehicles instead of manual driving. These autonomous vehicles require various LiDAR, Radar, ultrasonic sensors, and cameras to sense their surroundings. These sensors need to be placed externally due to a larger area to detect any incoming dangers. These sensors, due to their placement, may impact the airflow around the vehicle. The present paper discusses the change in flow characteristics of the vehicle, such as pressure, velocity, drag coefficient, and lift coefficient. The vehicle's drag coefficient is expected to reduce by 2.2%, and the lift coefficient is likely to decline by 23.7% compared to the case without the sensors. © 2021 IEEE

Hydrodynamic Analysis of Extra-Terrestrial Submarine in Lakes of Titan using CFD

Extra-terrestrial space exploration projects have been a matter of interest with many space agencies given the possibility of non - Earth life forms, life-nurturing environments, or the presence of valuable minerals within our solar system. The present study conducts an aerodynamic analysis on a submarine body capable of examining the extra-terrestrial seas of Titan, which is expected to harbor life forms using CFD. Computational Fluid Dynamics or CFD is used to analyze the aerodynamic properties of the submarine. The present case is set up by enabling the liquid properties like that of Titan's seas with submarine deeply submerged inside the lake moving at a velocity of 1 - 3 m/s. The average drag coefficient observed for the L/D ratios 10.8, 12.5, and 14.4 is 0.059, 0.067, and 0.072, respectively, for the assumed geometry when the submarine is submerged deep inside the seas. © 2021 IEEE

Development of Semi-autonomous Dragonfly based UAV in Free Flight Conditions

The bioinspired quad wing propulsion resembling dragonfly insect-based unmanned aerial vehicle (UAV) is designed and developed. Unmanned Aerial Vehicles or Drones are technological platforms, with various applications starting from photography to agriculture, passenger drones to ambulances, surveillance drones to combat drones, infrastructure asset maintenance, and power lines inspection. These drones can vary from minimal size to those which carry a heavy payload. This bioinspired quad wing UAV capable of hovering and gliding at low Reynolds number is being developed. This UAV consists of four wings subjected to combined heaving and pitching motions for improved efficiency. These wings are controlled individually to enhance energy-efficient and results in maneuverability. These wings beat at the resonance frequency, thereby harnessing the vibrational energy of the wings and reduces the amount of power required to flap the wings. The flapping amplitude and frequency can be controlled individually or combined using a gear drive that enables variable frequency control or variable amplitude control, or both modes. In this study, the aerodynamic characteristics of propulsive forces are measured using a force sensor in free flight conditions and are compared with the conventional quadcopter UAV propeller characteristics. Preliminary experiments on kinematics and prototypes testing during free flight conditions are presented. © 2021 IEEE

Chest radiographic manifestations of scrub typhus

Background and Rationale: Respiratory system involvement in scrub typhus is seen in 20–72% of patients. In endemic areas, good understanding and familiarity with the various radiologic findings of scrub typhus are essential in identifying pulmonary complications. Materials and Methods: Patients admitted to a tertiary care center with scrub typhus between October 2012 and September 2013 and had a chest X ray done were included in the analysis. Details and radiographic findings were noted and factors associated with abnormal X-rays were analyzed. Results: The study cohort contained 398 patients. Common presenting complaints included fever (100%), generalized myalgia (83%), headache (65%), dyspnea (54%), cough (24.3%), and altered sensorium (14%). Almost half of the patients (49.4%) had normal chest radiographs. Common radiological pulmonary abnormalities included pleural effusion (14.6%), acute respiratory distress syndrome (14%), airspace opacity (10.5%), reticulonodular opacities (10.3%), peribronchial thickening (5.8%), and pulmonary edema (2%). Cardiomegaly was noted in 3.5% of patients. Breathlessness, presence of an eschar, platelet counts of 2 mg/dL had the highest odds of having an abnormal chest radiograph. Patients with an abnormal chest X-ray had a higher requirement of noninvasive ventilation (odds ratio [OR]: 13.98; 95% confidence interval CI: 5.89–33.16), invasive ventilation (OR: 18.07; 95% CI: 6.42–50.88), inotropes (OR: 8.76; 95% CI: 4.35–17.62), higher involvement of other organ systems, longer duration of hospital stay (3.18 ± 3 vs. 7.27 ± 5.58 days; P< 0.001), and higher mortality (OR: 4.63; 95% CI: 1.54–13.85). Conclusion: Almost half of the patients with scrub typhus have abnormal chest radiographs. Chest radiography should be included as part of basic evaluation at presentation in patients with scrub typhus, especially in those with breathlessness, eschar, jaundice, and severe thrombocytopenia

Bioinspired Flapping Foil With Trailing Edge Flap For Remotely Operated Vehicles (ROVs)

Highly efficient propulsive mechanisms of aquatic swimming creatures could serve as inspiration for developing new propulsion methods where it exceeds the performance of present-day thrusters and propellers for ASVs, AUVs, and ROVs. The advantages of eco-friendly propulsion combined with a lesser wake could be advantageous for marine vehicles' stability and maneuvering. As a result, we need to improve our knowledge of fish or dolphin swimming hydrodynamics and their fluid-structure interaction to develop benchmark designs for new propulsion methods. Flapping foil thrusters for propulsion has sparked much interest in recent years. AUVs, ASVs, and ROVs vehicles could greatly benefit from this technology. In dolphin swimming kinematics, the flapping foil thruster is an essential component. This research aims to understand better the hydrodynamics and fluid-structure interaction of flapping foils subjected to heaving and pitching motions. In the present study, the bio-inspired flapping foil thrusters fitted with trailing edge flaps are studied experimentally using flow visualization techniques such as 2D particle image velocimetry (PIV). The time average vorticity contours and instantaneous velocity contours are presented in this study. The flapping foils with trailing edge flaps are immersed in a free stream of uniform flow speed varying from 5 to 10 cm/s. The operating Reynold number (Re) range is 500 to 4300. The Strouhal number range is 0.2 to 0.3. This study also investigated the effect of flapping foil without trailing edge flaps using 2D numerical simulations. By simulating the wake structure and its evolution, the present study aims to understand the vortex shedding mechanisms of flapping foil with or without trailing edge flaps, determining thrust and propulsive efficiency. The vortex shedding mechanisms for both the foils are presented and discussed in detail. © 2022 IEEE