Mechanical and analytical screening of braided composites for transport fuselage applications

The mechanics of materials progress in support of the goal of understanding the application of braided composites in a transport aircraft fuselage are summarized. Composites consisting of both 2-D and 3-D braid patterns are investigated. Both consolidation of commingled graphite/PEEK and resin transfer molding of graphite-epoxy braided composite processes are studied. Mechanical tests were used to examine unnotched tension, open hole tension, compression, compression after impact, in-plane shear, out-of-plane tension, bearing, and crippling. Analytical methods are also developed and applied to predict the stiffness and strengths of test specimens. A preliminary study using the test data and analytical results is performed to assess the applicability of braided composites to a commercial aircraft fuselage

Development of braided rope seals for hypersonic engine applications. Part 2: Flow modeling

Two models based on the Kozeny-Carmen equation were developed to analyze the fluid flow through a new class of braided rope seals under development for advanced hypersonic engines. A hybrid seal geometry consisting of a braided sleeve and a substantial amount of longitudinal fibers with high packing density was selected for development based on its low leakage rates. The models developed allow prediction of the gas leakage rate as a function of fiber diameter, fiber packing density, gas properties, and pressure drop across the seal

Learning Deep Latent Spaces for Multi-Label Classification

Multi-label classification is a practical yet challenging task in machine learning related fields, since it requires the prediction of more than one label category for each input instance. We propose a novel deep neural networks (DNN) based model, Canonical Correlated AutoEncoder (C2AE), for solving this task. Aiming at better relating feature and label domain data for improved classification, we uniquely perform joint feature and label embedding by deriving a deep latent space, followed by the introduction of label-correlation sensitive loss function for recovering the predicted label outputs. Our C2AE is achieved by integrating the DNN architectures of canonical correlation analysis and autoencoder, which allows end-to-end learning and prediction with the ability to exploit label dependency. Moreover, our C2AE can be easily extended to address the learning problem with missing labels. Our experiments on multiple datasets with different scales confirm the effectiveness and robustness of our proposed method, which is shown to perform favorably against state-of-the-art methods for multi-label classification.Comment: published in AAAI-201

The Readability Of Instructions For Income Taxation In The Western States

The taxation of individual income represents an important revenue source for many states. The taxes are determined by a self-assessed tax system from information that is the declaration of the taxpayer in an annual return. State taxation agencies facilitate compliance by furnishing individuals with the necessary forms and instruction materials needed to prepare the self-assessed tax return. This study reports on a readability assessment of the income tax instructions for states in the West. The results find improvements in the readability averages for tax instructions between 1990 and 2005, but in absolute terms the instructions for Western states are difficult to read. State income tax instructions have a readability level that currently exceeds the educational attainment level of nearly half the adult population in the West

Development of braided rope seals for hypersonic engine applications: Flow modeling

A new type of engine seal is being developed to meet the needs of advanced hypersonic engines. A seal braided of emerging high temperature ceramic fibers comprised of a sheath-core construction was selected for study based on its low leakage rates. Flexible, low-leakage, high temperature seals are required to seal the movable engine panels of advanced ramjet-scramjet engines either preventing potentially dangerous leakage into backside engine cavities or limiting the purge coolant flow rates through the seals. To predict the leakage through these flexible, porous seal structures new analytical flow models are required. Two such models based on the Kozeny-Carman equations are developed herein and are compared to experimental leakage measurements for simulated pressure and seal gap conditions. The models developed allow prediction of the gas leakage rate as a function of fiber diameter, fiber packing density, gas properties, and pressure drop across the seal. The first model treats the seal as a homogeneous fiber bed. The second model divides the seal into two homogeneous fiber beds identified as the core and the sheath of the seal. Flow resistances of each of the main seal elements are combined to determine the total flow resistance. Comparisons between measured leakage rates and model predictions for seal structures covering a wide range of braid architectures show good agreement. Within the experimental range, the second model provides a prediction within 6 to 13 percent of the flow for many of the cases examined. Areas where future model refinements are required are identified

Engine panel seals for hypersonic engine applications: High temperature leakage assessments and flow modelling

A critical mechanical system in advanced hypersonic engines is the panel-edge seal system that seals gaps between the articulating horizontal engine panels and the adjacent engine splitter walls. Significant advancements in seal technology are required to meet the extreme demands placed on the seals, including the simultaneous requirements of low leakage, conformable, high temperature, high pressure, sliding operation. In this investigation, the seal concept design and development of two new seal classes that show promise of meeting these demands will be presented. These seals include the ceramic wafer seal and the braided ceramic rope seal. Presented are key elements of leakage flow models for each of these seal types. Flow models such as these help designers to predict performance-robbing parasitic losses past the seals, and estimate purge coolant flow rates. Comparisons are made between measured and predicted leakage rates over a wide range of engine simulated temperatures and pressures, showing good agreement

Signatures for doubly-charged Higgsinos at colliders

Several supersymmetric models with extended gauge structures predict light doubly-charged Higgsinos. Their distinctive signature at the large hadron collider is highlighted by studying their production and decay characteristics.Comment: 3 pages, 4 figures, Latex. Submitted for SUSY 2008 proceeding

In Vivo Noninvasive Mouse Model Of Load Induced Osteoarthritis

Osteoarthritis (OA) is the leading cause of disability among the elderly population, affecting approximately 27 millions Americans and costing $60 billion in related-health care costs. Mouse models of OA have been developed to study the mechanisms of OA and therapeutic interventions. However, traditional animal models induce OA pathology through traumatic surgeries, which only represent 10% of human OA patients. Thus, in this thesis, a novel noninvasive OA mouse model was developed, characterized, and applied to transgenic mice. The changes in articular cartilage and subchondral bone were analyzed by histology, immunohistochemistry, and microcomputed tomography. To develop a noninvasive OA mouse model, an in vivo tibial loading model was used to investigate the adaptive responses of cartilage and bone to mechanical loading and to assess the influence of load level and duration. Peak cyclic compression of 4.5 and 9.0N was applied to the left tibia via the knee joint of adult (26-week-old) male mice for 1, 2, and 6 weeks at 1200 cycles/day. In addition, 9.0N loading was utilized in young (10-week-old) mice. Loading promoted cartilage damage, cartilage thinning, and subchondral cortical bone thickening in both age groups. Both age groups developed periarticular osteophytes at the tibial plateau in response to the 9.0N load, but no osteophyte formation occurred in adult mice subjected to 4.5N load. Development of a novel noninvasive loading model was followed by investigating the traumatic vs. nontraumatic nature of cyclic loading of the mouse knee joint. To differentiate traumatic tissue damage versus cell-mediated processes in the development of OA pathology, a single nondestructive 5-minute loading session was applied to the left tibia of adult (26-weekold) mice at a peak load of 9.0N. Knee joints were subsequently analyzed at 0, 1 and 2 weeks after loading. At T = 0, no change was evident in cartilage or subchondral bone. However, cartilage pathology demonstrated by localized thinning, proteoglycan loss, and inhibition of chondrocyte autophagy occurred at 1 and 2 weeks after the single session of loading. Transient cancellous bone loss was evident at 1 week, associated with increased osteoclast number, reversed at 2 weeks. Finally, the in vivo tibial loading model was implemented to study the role of Dickkopf1, an inhibitor of the Wnt pathway, in the development of load-induced OA. To identify the role of Dickkopf-1 protein in OA, novel viable mice with Dickkopf-1 knockout and Wnt3 knockdown (Dkk1-/-;Wnt3+/-) were used. The left tibia of 10-week-old Dkk1-/-;Wnt3+/- and respective control groups, littermate control (Dkk1+/+;Wnt3+/+) and Wnt3 knockdown (Dkk1+/+;Wnt3+/-) mice, underwent cyclic compression at a peak load of 9.0N for 2 weeks. As a result of loading, both Dkk1-/-;Wnt3+/- and Dkk1+/+;Wnt3+/+ mice demonstrated cartilage erosion, subchondral cancellous bone loss, and osteophyte formation. However, Dkk1+/+;Wnt3+/- mice did not undergo cartilage degeneration and showed limited osteophyte formation, indicating knockdown of Wnt3's potential chondroprotection against an altered joint loading environment. In summary, an altered joint loading environment caused by in vivo tibial loading repeatedly and robustly produced OA pathology in mouse joints. This loading modality was nontraumatic as evidenced by the absence of physical damage and presence of biological events that led to OA. In addition, the in vivo tibial loading model can be applied to investigate potential chondroprotection from genetic or pharmacological interventions. The novel in vivo tibial loading model presents tremendous opportunities to study the etiology of OA from patients without a history of traumatic joint injury and will be an excellent platform to develop therapeutic interventions

Pharmacological utilization of bergamottin, derived from grapefruits, in cancer prevention and therapy

In spite of significant advances in treatment options and the advent of novel targeted therapies, there still remains an unmet need for the identification of novel pharmacological agents for cancer therapy. This has led to several studies evaluating the possible application of natural agents found in vegetables, fruits, or plant-derived products that may be useful for cancer treatment. Bergamottin is a furanocoumarin derived from grapefruits and is also a well-known cytochrome P450 inhibitor. Recent studies have demonstrated potent anti-oxidative, anti-inflammatory, and anti-cancer properties of grapefruit furanocoumarin both in vitro and in vivo. The present review focuses on the potential anti-neoplastic effects of bergamottin in different tumor models and briefly describes the molecular targets affected by this agent