Review and prospect of supersonic business jet design

This paper reviews the environmental issues and challenges appropriate to the design of supersonic business jets (SSBJs). There has been a renewed, worldwide interest in developing an environmentally friendly, economically viable and technologically feasible supersonic transport aircraft. A historical overview indicates that the SSBJ will be the pioneer for the next generation of supersonic airliners. As a high-end product itself, the SSBJ will likely take a market share in the future. The mission profile appropriate to this vehicle is explored considering the rigorous environmental constraints. Mitigation of the sonic boom and improvements aerodynamic efficiency in flight are the most challenging features of civil supersonic transport. Technical issues and challenges associated with this type of aircraft are identified, and methodologies for the SSBJ design are discussed. Due to the tightly coupled issues, a multidisciplinary design, analysis and optimization environment is regarded as the essential approach to the creation of a low-boom low-drag supersonic aircraft. Industrial and academic organizations have an interest in this type of vehicle are presented. Their investments in SSBJ design will hopefully get civil supersonic transport back soon

Inequalities and bounds for quasi-symmetric 3-designs

AbstractQuasi-symmetric 3-designs with block intersection numbers x and y(0⩽x<y<k) are studied, several inequalities satisfied by the parameters of a quasi-symmetric 3-designs are obtained. Let D be a quasi-symmetric 3-design with the block size k and intersection numbers x, y; y>x⩾1 and suppose D′ denote the complement of D with the block size k′ and intersection numbers x′ and y′. If k −1 ⩽x + y then it is proved that x′ + y′ ⩽ k′. Using this it is shown that the quasi-symmetric 3-designs corresponding to y = x + 1, x + 2 are either extensions of symmetric designs or designs corresponding to the Witt-design (or trivial design, i.e., v = k + 2) or the complement of above designs

3D Reconstruction of Interventional Material from Very Few X-Ray Projections for Interventional Image Guidance

Today, minimally invasive endovascular interventions are usually guided by 2D fluoroscopy, i.e. a live 2D X-ray image. However, 3D fluoroscopy, i.e. a live 3D image reconstructed from a stream of 2D X-ray images, could improve spatial awareness. 3D fluoroscopy is, however, not used today, since no appropriate 3D reconstruction algorithm is known. Existing algorithms for the real-time reconstruction of interventional material (guidewires, stents, catheters, etc.) are either only capable of reconstructing a single guidewire or catheter, or use too many X-ray images and therefore too much dose per 3D reconstruction. The goal of this thesis was to reconstruct complex arrangements of interventional material from as few X-ray images as possible. To this end, a previously proposed algorithm for the reconstruction of interventional material from four X-ray images was adapted. Five key improvements allowed to reduce the number of X-ray images per 3D reconstruction from four to two: a) use of temporal information in a rotating imaging setup, b) separate reconstruction of different types of interventional material enabled by the computation of semantic interventional material extraction images, c) compensation of stent motion by spatial transformer networks, d) per-projection backprojection and e) binarization of the guidewire extraction images. While previously only single curves could be reconstructed from two newly acquired X-ray images, the proposed pipeline can reconstruct stents and even stent-guidewire combinations. Submillimeter reconstruction accuracy was demonstrated on measured X-ray images of interventional material inside an anthropomorphic phantom with simulated respiratory motion. Measurements of the dose area product rate of the proposed 3D reconstruction pipeline indicate a dose burden roughly similar to that of 2D fluoroscopy

Nonfluoroscopic electromechanical mapping of the left ventricle: Evaluation of the technique as diagnostic tool and as guidance for novel therapeutic strategies

With his landmark paper in Nature Medicine in 1996, Shlomo Ben-Baim and coworkers introduced a novel technique into the clinical arena. In

Enabling Studies to Optimize Biomaterials for the Treatment of Myocardial Infarction

The canonical mechanism of wound healing is disrupted following a myocardial infarction (MI), manifesting as an unregulated response that negatively impacts left ventricular (LV) function. This mechanism, termed post-MI remodeling, culminates in an outcome that favors progression to a systolic heart failure state and death for the patient. Therapeutic approaches following the occurrence of a MI are designed to modulate the natural remodeling process and mitigate the loss of cardiac function. The mechanics and structure of the healing infarct have been the focus of numerous pre-clinical and clinical investigations, leading to the impending clinical introduction of material injections as a means to favorably alter remodeling outcomes. However, to date there is no body of work that provides a coherent framework for evaluation of targeted material therapies. To form a basis for optimization of material-based MI treatments, we have integrated measurements of MI regional mechanics, the morphology of the local extracellular matrix, and the biophysical impact of material injections into the MI region in a porcine model of MI. The combined findings of this study have enhanced a mechanistic understanding of material-based post-MI interventions, elucidated the relationship between MI regional mechanics and LV function throughout the natural and attenuated history of LV remodeling, and has developed mechanical metrics of value to move forth towards future developments of a generalizable computational tools for screening and evaluation of new strategies for MI injections

Proceedings of the 6th Annual Summer Conference: NASA/USRA University Advanced Design Program

The NASA/USRA University Advanced Design Program is a unique program that brings together NASA engineers, students, and faculty from United States engineering schools by integrating current and future NASA space/aeronautics engineering design projects into the university curriculum. The Program was conceived in the fall of 1984 as a pilot project to foster engineering design education in the universities and to supplement NASA's in-house efforts in advanced planning for space and aeronautics design. Nine universities and five NASA centers participated in the first year of the pilot project. The study topics cover a broad range of potential space and aeronautics projects that could be undertaken during a 20 to 30 year period beginning with the deployment of the Space Station Freedom scheduled for the mid-1990s. Both manned and unmanned endeavors are embraced, and the systems approach to the design problem is emphasized

Aerospace Medicine and Biology: A continuing bibliography with indexes (supplement 261)

This bibliography lists 281 reports, articles and other documents introduced into the NASA scientific and technical information system in July 1984

Conceptual Layout of Wing Structure using Topology Optimization for Morphing Micro Air Vehicles in a Perching Maneuver

A topology optimization model for conceptual wing structure layouts of morphing micro air vehicles (MAVs) has been developed and implemented in MATLAB. Specifically, a six degree-of-freedom finite element (FE) model with a general quadrilateral discretization scheme was created by superposition of a known simple linear plane membrane element and a Kirchhoff plate bending element derived herein. The purpose of the six degree-offreedom model was to accommodate in-plane and out-of-plane aerodynamic loading combinations. The FE model was validated and the MATLAB implementation was verified with classical beam and plate solutions. A compliance minimization optimization objective was then formulated with the Solid Isotropic Material with Penalization (SIMP) method, subject to the equilibrium constraint computed by the FE model, and solved with the Optimality Criteria (OC) method. With the topology optimization model in place, four aerodynamic loading scenarios were extracted from points along a feasible MAV perching flight trajectory and used to determine wing thickness distributions for given planform shapes. The results suggest conceptual structural layouts in morphing MAVs, but equally important, the simple MATLAB implementation of the model can be adapted for a variety of objective statements for MAV morphing wing design