Long-Term Rehabilitation Outcomes of Neurological Patients: A Multicenter Study

Objective: To evaluate functional outcomes in patients three years after rehabilitation and to identify factors significantly associated with improvement. Materials and Methods: This prospective cohort study was carried out in nine tertiary centers to compare functional outcomes (Barthel Index; BI) at discharge with scores at three-year follow-up among various diagnoses and types of admissions. Related factors were evaluated for association with improvement in functional score. Results: Three hundred and eighteen patients (mean age: 54 years; 60% male) were included. More than half of all patients suffered from a spinal cord injury. After three years, 35% of patients were still receiving physical therapy. Only those who were admitted for intensive rehabilitation showed significant improvement after three years. One hundred and ten patients or 35.8% showed significant improvement over time. A univariate analysis showed type of diagnosis, type of admission, onset to admission interval, BI at discharge, and presence of depression and complications at follow-up to be significantly associated with improvements in functional score in the follow-up period. Using a multivariate analysis, only the type of diagnosis, low BI at discharge, and absence of depression and complications at follow-up related to functional improvement. Conclusion: One-third of patients had sustained functional improvements from rehabilitation three years after discharge. Participants admitted into intensive rehabilitation showed significant improvements in functional scores between discharge and follow-up. TBI diagnosis, low BI at discharge, absence of depression and complications at follow-up related to long-term functional improvement at the three-year mark

The Investigation of an Inboard-Winglet Application to a Roadable Aircraft

The inboard-winglet concept was examined for its flow characteristics by testing for pressure coefficients over the wing and winglet surface in the Virginia Tech Stability Wind Tunnel over a range of freestream velocity and angle of attack. The results were analytically applied to calculate aircraft performance of a roadable aircraft, Pegasus II, which used the inboard-winglet concept in its design. The results proved that this concept has the potential to increase a wing lift coefficient at the right combination of thrust setting and freestream velocity better than a conventional wing-propeller arrangement. The lift coefficient inside the winglet channel was approximated as 2D in behavior. It is also shown that the winglets produce thrust at a positive-lift wing configuration. In the Pegasus II, the vertical stabilizers act like inboard winglets and produce a thrust component from its resultant force, giving 5.2% improvement in its effective aspect ratio and resulting in an induced-drag decrease. With an application of the new wing concept, the Pegasus II performance is comparable to other general aviation aircraft.Master of Scienc

Formation and Development of the Tip Leakage Vortex in a Simulated Axial Compressor with Unsteady Inflow

The interaction between rotor blade tip leakage vortex and inflow disturbances, such as encountered in shrouded marine propulsors, was simulated in the Virginia Tech Linear Cascade Wind Tunnel equipped with a moving endwall system. Upstream of the blade row, idealized periodic inflow unsteadiness was generated using vortex generator pairs attached to the endwall at the same spacing as the blade spacing. At three tip gap settings, 1.7%c, 3.3%c and 5.7%c, the flow near the lower endwall of the center blade passage was investigated through three-component mean velocity and turbulence distributions measured by four-sensor hotwires. Besides time-averaged data, the measurements were processed for phase-locked analysis, with respect to pitchwise locations of the vortex generators relative to the blade passage. Moreover, surface pressure distributions at the blade tip were acquired at eight tip gaps from 0.87%c to 12.9%c. Measurements of pressure-velocity correlation were also performed with wall motion but without inflow disturbances. Achieved in this study is an understanding of the characteristics and structures of the tip leakage vortex at its initial formation. The mechanism of the tip leakage vortex formation seems to be independent of the tip gap setting. The tip leakage vortex consists of a vortical structure and a region of low streamwise-momentum fluid next to the endwall. The vortical structure is initially attached to the blade tip that creates it. This structure picks up circulation shed from that blade tip, as well as those from the endwall boundary layer, and becomes stronger with downstream distance. Partially induced by the mirror images in the endwall, the vortical structure starts to move across the passage resulting in a reduction in its rotational strength as the cross sectional area of the vortex increases but little circulation is added. The larger the tip gap, the longer the vortical structure stays attached to the blade tip, and the stronger the structure when it reaches downstream of the passage. Phased-averaged data show that the inflow disturbances cause small-scale responses and large-scale responses upstream and downstream of the vortex shedding location, respectively. This difference in scale is possibly dictated by a variation in the shedding location since the amount of circulation in the vortex is dependent on this location. The inflow disturbances possibly cause a variation in the shedding location by manipulating the separation of the tip leakage flow from the endwall and consequently the flow's roll-up process. Even though this manipulation only perturbs the leakage flow in a small scale, the shedding mechanism of the tip leakage vortex amplifies the outcome.Ph. D

Laser Displacement Sensors for Wind Tunnel Model Position Measurements

Wind tunnel measurements of two-dimensional wing sections, or airfoils, are the building block of aerodynamic predictions for many aerodynamic applications. In these experiments, the forces and pitching moment on the airfoil are measured as a function of the orientation of the airfoil relative to the incoming airflow. Small changes in this angle (called the angle of attack, or α ) can create significant changes in the forces and moments, so accurately measuring the angle of attack is critical in these experiments. This work describes the implementation of laser displacement sensors in a wind tunnel; the sensors measured the distance between the wind tunnel walls and the airfoil, which was then used to calculate the model position. The uncertainty in the measured laser distances, based on the sensor resolution and temperature drift, is comparable to the uncertainty in traditional linear encoder measurements. Distances from multiple sensors showed small, but statistically significant, amounts of model deflection and rotation that would otherwise not have been detected, allowing for an improved angle of attack measurement

Aerodynamics Study of Fixed-Wing MAV: Wind Tunnel and Flight Test

Obtaining accurate aerodynamic characteristics of in-flight Micro Air Vehicles (MAVs) was viewed as difficult, due to the nature of very low Reynolds number, 3D complex flow, and strong influence from propulsion slipstream. This paper presents the study of the tailless, fixed-wing MAV, KuMAV-001, performed at Kasetsart University. The team investigated different analysis and testing methods to determine the aerodynamics characteristics of this MAV. The Vortex Lattice Method was introduced in the conceptual design phase and helped with the evaluation of the 3D effects for winglet configurations. The wind tunnel tests with main wing and fully configured MAV were conducted for powered and unpowered models. The influence of propulsion-induced flows on CL, CD, and CM(cg) was investigated during the wind tunnel testing. Verification of the performance results are to be completed with flight test data in the future

Identifying drone-related security risks by a laser vibrometer-based payload identification system

Various drone detection systems (DDS) have been recently developed for civil and military applications. Such DDS are generally based on radio frequency (RF) radars, detecting control signals between drones and their pilots, drone's acoustic noise, optical surveillance, or a combination of these. However, existing DDS have safety critical gaps. For example, none of the current state-of-the-art technologies provide remote payload monitoring or verification. The registered payload of some commercial drones can be greatly increased by simple re-configuration procedures that may not be detected by current DDS. This study introduces patent-pending methods for remote identification and payload monitoring of standard and modified drones. Structural frequencies, measured by a long-range laser vibrometer, of commercial drones are proposed as a unique signature for remotely verifying registered specifications of a drone, e.g., payload capacity. In addition, a method is proposed to measure payload capacity of unknown drones based on their motion performance monitored via a motion dynamic model and a laser Doppler vibrometer. Preliminary flight tests have been successfully conducted for a group of standard and modified drones by the Institute of Flight Systems, DLR (German Aerospace Center