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

Synthesis and Antimicrobial Activity of Novel 3-[1-(3-nitrophenyl)-ethyl]-1-(indole-1-yl) Substituted Aryl/alkyl-phosphinoyl/thiophosphinoyl/ selenophosphinoyl-1H-indole Derivatives

Syntheses of novel 3-[1-(3-nitrophenyl)-ethyl]-1-(indole-1-yl) substituted aryl/alkyl phosphinoyl/thiophosphinoyl/selenophosphinoyl-1H-indole derivatives were accomplished in two steps. The synthetic route involves the cyclisation of equimolar quantities of 3-[1H-3-indolyl(3-nitrophenyl)methyl]-1H-indole with dichlorophenyl phosphine/ethyldichlorophosphite in the presence of triethylamine in dry acetonitrile at room temperature. These compounds were further converted to the corresponding oxides, sulphides and selenides by reacting them with hydrogen peroxide, sulphur and selenium, respectively. The structures of the novel products were established by elemental analyses, IR, 1H, 13C and 31P NMR and mass spectroscopy. They were screened for antibacterial and antifungal activity against Staphylococcus aureus/Klebsiella pneumoniae and Pellicularia solmanicolor/Macrophomina phaseolina, respectively.Keywords: Bisindolylalkanes, alkyl/aryl phosphorodichloridates, antimicrobial activit

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

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

Autonomous Emergency Breaking (AEB) Evaluation For Indian Traffic Scenarios using GPS and LiDAR Data

Autonomous emergency braking (AEB) and forward-collision warning (FCW) is a cutting-edge active safety technology that assists drivers in avoiding or minimizing crashes with global cars and other vulnerable road users (VRU) for SAE autonomy Level 3 and 4 categories. The Indian traffic scenario data is recorded for Hyderabad city using Lidar and GPS sensors. This dataset is available at IIIT Hyderabad. This real-world traffic scenario is converted into a virtual closed-loop scenario for evaluating AEB and FCW for different VRUs in this present study. The synthetic Radar and camera data are generated by the radar detection generator and vision detection generator blocks in the driving scenario simulator. The results of the virtual scenario developed using sensor perception reveals the ego car velocity ego car acceleration when the lead vehicle's time-to-collision (TTC) is less than FCW. The simulation results are observed for a total of 9 seconds. The control algorithms for AEB and FCW prevent accidents with rear-end collisions of global vehicles, and accurate world traffic scenario data assessed its performance. © 2022 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

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

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

Future Mobility with eVTOL Personal Air Vehicle (PAV): Urban Air Mobility (UAM) Concept

Many countries consider Urban Air Mobility (UAM) a new mode of transportation for intra-regional short-distance journeys. The system is one of the upcoming on-demand airborne transportation networks and includes drone taxis and personal air vehicles. The primary purpose of the UAM concept is to use electric vertical take-off and landing (eVTOL) vehicles to identify passenger locations, fly and cruise, load the passengers, and deliver them to their destinations. UAM system is a currently evolving field, and multiple concepts such as multi-copter concepts, Lift and Cruise concepts, and Tilt-Wing concepts are being proposed. The behavior of each concept vehicle, and hence its energy efficiency, varies. Using low-altitude airspace, UAM is intended to provide an innovative transportation model for passengers and goods in metropolitan areas with significantly increased mobility. Ground infrastructure incorporating vertiports, regulations, policies, and other vital components, is required to transform UAM from design to operation. Electric flight is thought to be the next step toward more environmentally sustainable air travel. In the present study, a personal air vehicle (PAV) based eVTOL concept is proposed for UAM. The preliminary design and modelling of PAV are discussed here. The aerodynamic performance of propeller characteristics used in PAV design is compared using numerical and experimental studies. The results show that at different velocities, the normal and side forces generated by the propellers are found to be more stable in PAV cruise mode/ forward flight mode, respectively. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd