Flying after diving: a questionnaire-based evaluation of pre-flight diving behaviour in a recreational diving cohort

Introduction: Divers are recommended to observe a pre-flight surface interval (PFSI) ≥ 24 hours before boarding a plane following a diving vacation. Decompression sickness (DCS) symptoms may occur during or post-flight. This study aimed to examine the adherence of PFSI ≥ 24 in vacationing divers, and if any perceived signs and symptoms of DCS during or after flight were experienced. Methods: An anonymous online survey was publicised through diving exhibitions and social media. Data included diver/diving demographics, PFSI before flight, flight details, and perceived signs and symptoms of DCS during or after flight. Results: Data from 316 divers were examined (31% female) with the age range 1-75 years (median 49). Divers recorded 4,356 dives in the week preceding the flight, range 1-36 (median 14). Overall, 251/316 (79%) respondents reported a PFSI of ≥ 24 hours. PFSIs of < 12 hours were reported by 6 respondents. Diagnosed and treated DCS developing during, and post flight was reported by 4 divers with PFSIs ≥ 24 hours and by 2 divers with PFSIs < 24 hours. Fifteen divers boarded a plane with perceived symptoms of DCS. Conclusions: These data suggest that most divers in this study observed the recommendations of a ≥ 24 hour PFSI with safe outcomes.

PollMap: a software for crop pollination mapping in agricultural landscapes

Background Ecosystem service mapping is an important tool for decision-making in landscape planning and natural resource management. Today, pollination service mapping is based on the Lonsdorf model (InVEST software) that determines the availability of nesting and floral resources for each land cover and estimates pollination according to the foraging range of the desired species. However, it is argued that the Lonsdorf model has significant limitations in estimating pollination in a landscape that can affect the results of this model. Results This paper presents a free software, named PollMap, that does not have the limitations of the Lonsdorf model. PollMap estimates the pollination service according to a modified version of the Lonsdorf model and assumes that only cells within the flight range of bees are important in the pollination mapping. This software is produced for estimating and mapping crop pollination in agricultural landscapes. The main assumption of this software is that in the agricultural landscapes, which are dominated by forest and agriculture ecosystems, forest patches serve only as a nesting habitat for wild bees and the surrounding fields provide floral resources. Conclusion The present study provided new software for mapping crop pollination in agricultural landscapes that does not have the limitations of the Lonsdorf model. We showed that the use of the Lonsdorf model for pollination mapping requires attention to the limitations of this model, and by removing these limitations, we will need new software to obtain a reliable mapping of pollination in agricultural landscapes.

ОЦІНКА ВПЛИВУ ЦЕНТРУВАННЯ НА АЕРОДИНАМІЧНУ ЯКІСТЬ, ПОЛЯРУ І ДАЛЬНІСТЬ ПОЛЬОТУ ЛІТАКА

The method of transport category airplane flight range estimation taking into account its center-of-gravity position variation in the process of fuel utilization at cruising flight mode is presented. The method structure includes the following models:– Interinfluence of main parameters on each other in the process of fuel utilization;– Estimation of CG position influence on lift-to-drag ratio in cruising mode;– Quantitative estimation of center-of-gravity position variation influence on airplane flight range.Simulation of the main parameters is based on authoring researches, establishing interinfluence among geometrical and aerodynamic parameters of wing, parameters of horizontal tail and center-of-gravity position variation caused by fuel utilization in cruise flight. Such model allows estimating airplane center-of-gravity influence on their values and relative position.Aerodynamic parameters variation caused by center-of-gravity shift resulted in necessity to take the influence into account, for required engine thrust variation; that is shown in the publication in the form of dependences allowing to take into account the required thrust variation and their influence on range variation.On the base of interinfluence model and taking into account required thrust variation (with center-of-gravity position shift), lift-to-drag variation has been obtained and analyzed in the form of dependences , for middle airplane of transport category.Expression for estimation of airplane flight range under variable values of its mass and center-of-gravity position is obtained on the base of these models; that allows to increase flight range by means of center-of-gravity position dedicated shift.On the example of mid-range transport airplane, it is shown, that at Mach number and center-of-gravity shift back from to , the increase of flight range makes .On the base of presented models, it is shown, that airplane center-of-gravity position influences lift-to-drag ratio, fuel efficiency and as a result on flight range at cruising flight mode.Application of aft center-of-gravity position allows to decrease engine required thrust (and to decrease fuel consumption), and increase lift-to-drag ratio and airplane flight range.

Algorithm and design improvements for indirect time of flight range imaging cameras

<p>This thesis describes the development of a compact and modularised indirect time of flight range imaging camera. These cameras commonly use the Amplitude Modulated Continuous Wave (AMCW) technique. For this technique, an entire scene is illuminated with light modulated at a high frequency. An image sensor is also modulated and the phase shift introduced between the two modulation signals, due to the transit time of the light reflecting off objects in the scene and returning to the camera, is used to measure the distance. The system constructed for this thesis is controlled by a Cyclone III FPGA and is capable of producing full field of view range images in real time with no additional computational resources. A PMD19K-2 sensor is used as the modulatable image sensor, and is capable of modulation frequencies up to 40 MHz. One significant issue identified with this range imaging technology is that the precision of the range measurements are often dependent on the properties of the object being measured. The dynamic range of the camera is therefore very important when imaging high contrast scenes. Variable Frame Rate Imaging is a novel technique that is developed as part of this thesis and is shown to have promise for addressing this issue. Traditional theory for indirect time of flight cameras is expanded to describe this technique and is experimentally verified. A comparison is made between this technique and traditional High Dynamic Range Imaging. Furthermore, this technique is extended to provide a constant precision measurement of a scene, regardless of the properties of the objects in the scene. It is shown that the replacement of the standard phase detection algorithm with a different algorithm can both reduce the linearity error in the phase measurements caused by harmonics in the correlation waveform and ameliorate axial motion error caused by relative motion of the camera and the object being measured. The new algorithm requires a trivial increase in computational power over the standard algorithm and can be implemented without any significant changes to the standard hardware used in indirect time of flight cameras. Finally, the complete system is evaluated in a number of real world scenarios. Applications in both 3D modelling and mobile robotics are demonstrated and tests are performed for a variety of scenarios including dynamic scenes using a Pioneer 2 robot.</p>

Algorithm and design improvements for indirect time of flight range imaging cameras

<p>This thesis describes the development of a compact and modularised indirect time of flight range imaging camera. These cameras commonly use the Amplitude Modulated Continuous Wave (AMCW) technique. For this technique, an entire scene is illuminated with light modulated at a high frequency. An image sensor is also modulated and the phase shift introduced between the two modulation signals, due to the transit time of the light reflecting off objects in the scene and returning to the camera, is used to measure the distance. The system constructed for this thesis is controlled by a Cyclone III FPGA and is capable of producing full field of view range images in real time with no additional computational resources. A PMD19K-2 sensor is used as the modulatable image sensor, and is capable of modulation frequencies up to 40 MHz. One significant issue identified with this range imaging technology is that the precision of the range measurements are often dependent on the properties of the object being measured. The dynamic range of the camera is therefore very important when imaging high contrast scenes. Variable Frame Rate Imaging is a novel technique that is developed as part of this thesis and is shown to have promise for addressing this issue. Traditional theory for indirect time of flight cameras is expanded to describe this technique and is experimentally verified. A comparison is made between this technique and traditional High Dynamic Range Imaging. Furthermore, this technique is extended to provide a constant precision measurement of a scene, regardless of the properties of the objects in the scene. It is shown that the replacement of the standard phase detection algorithm with a different algorithm can both reduce the linearity error in the phase measurements caused by harmonics in the correlation waveform and ameliorate axial motion error caused by relative motion of the camera and the object being measured. The new algorithm requires a trivial increase in computational power over the standard algorithm and can be implemented without any significant changes to the standard hardware used in indirect time of flight cameras. Finally, the complete system is evaluated in a number of real world scenarios. Applications in both 3D modelling and mobile robotics are demonstrated and tests are performed for a variety of scenarios including dynamic scenes using a Pioneer 2 robot.</p>

Transport category airplane flight range calculation accounting center-of-gravity position shift and engine throttling characteristics

A problem facing world commercial aviation is a provision of the flight range and an increase in the fuel efficiency of transport category airplanes using fuel trim transfer application, which allows for decreasing airplane trim drag at cruise flight. In the existing mathematical models, center-of-gravity position is usually assumed fixed, but with fuel usage, center-of-gravity shifts within the definite range of center-of-gravity positions. Until the fuel trim transfer was not used in airplanes, the center-of-gravity shift range was rather short, that allowed to use the specified assumption without any considerable mistakes. In case of fuel trim transfer use, center-of-gravity shifts can reach 15…20 % of mean aerodynamic chord, that requires considering the center-of-gravity actual position during the flight range calculation. Early made estimated calculations showed the necessity of following mathematical model improvement using accounting the real engine throttling characteristics. The goal of this publication is to develop a method of flight range calculation taking transport category airplane into account actual center-of-gravity position with fuel using and variation in engine-specific fuel consumption according to their throttling characteristics. On the basis of real data from engine maintenance manuals, formulas are obtained for approximation throttling characteristics of turbofan engines in the form of dimensionless specific fuel consumption (related to the specific fuel consumption at full thrust) dependence on the engine throttling coefficient. A mathematical model (algorithm and its program implementation using С language in Power Unit 11.7 R03 system) has been developed to calculate the airplane flight range accounting its actual center-of-gravity position shift with fuel usage and variation in specific fuel consumption according to engine throttling characteristics. Using comparison with known payload-range diagram, adequacy of developed mathematical model is shown. Recommendations to improve the mathematical model are also given.