Application of the Finite Element Method to Rotary Wing Aeroelasticity

A finite element method for the spatial discretization of the dynamic equations of equilibrium governing rotary-wing aeroelastic problems is presented. Formulation of the finite element equations is based on weighted Galerkin residuals. This Galerkin finite element method reduces algebraic manipulative labor significantly, when compared to the application of the global Galerkin method in similar problems. The coupled flap-lag aeroelastic stability boundaries of hingeless helicopter rotor blades in hover are calculated. The linearized dynamic equations are reduced to the standard eigenvalue problem from which the aeroelastic stability boundaries are obtained. The convergence properties of the Galerkin finite element method are studied numerically by refining the discretization process. Results indicate that four or five elements suffice to capture the dynamics of the blade with the same accuracy as the global Galerkin method

The Ombudsman in Nova Scotia and Newfoundland

The Ombudsman is a relative newcomer to Canadian provincial government.\u27 The senior Canadian Ombudsman offices are located in Alberta and New Brunswick, both ten years old. The Nova Scotia Ombudsman has functioned for six years, and Newfoundland\u27s Parliamentary Commissioner for a mere two years. It may therefore be too early to analyze their degree of institutionalization. The concept does enable us, however, to focus our attention on the most important questions regarding the early history of the Ombudsman institution in the Maritimes. According to S. P. Huntingdon, institutionalization may be resolved into two internal components, complexity and coherence, and two external components, autonomy and adaptability. The two most important external actors which affect the emergent Ombudsman institution are politicians, who created the office, and civil servants, who are the Ombudsman\u27s main targets. This paper examines the attitudes and behaviour of politicians and civil servants to see whether in fact the Ombudsman is becoming institutionalized in these provinces

Aeroelasticity and structural optimization of composite helicopter rotor blades with swept tips

This report describes the development of an aeroelastic analysis capability for composite helicopter rotor blades with straight and swept tips, and its application to the simulation of helicopter vibration reduction through structural optimization. A new aeroelastic model is developed in this study which is suitable for composite rotor blades with swept tips in hover and in forward flight. The hingeless blade is modeled by beam type finite elements. A single finite element is used to model the swept tip. Arbitrary cross-sectional shape, generally anisotropic material behavior, transverse shears and out-of-plane warping are included in the blade model. The nonlinear equations of motion, derived using Hamilton's principle, are based on a moderate deflection theory. Composite blade cross-sectbnal properties are calculated by a separate linear, two-dimensional cross section analysis. The aerodynamic loads are obtained from quasi-steady, incompressible aerodynamics, based on an implicit formulation. The trim and steady state blade aeroelastic response are solved in a fully coupled manner. In forward flight, where the blade equations of motion are periodic, the coupled trim-aeroelastic response solution is obtained from the harmonic balance method. Subsequently, the periodic system is linearized about the steady state response, and its stability is determined from Floquet theory

Calcium Hydroxylapatite-Induced Inflammatory Facial Edema and Induration Due to Hashimoto\u27s Thyroiditis

We describe a patient who experienced a diffuse, treatment-refractory facial inflammatory reaction following the injection of calcium hydroxylapatite with lidocaine. The reaction was attributed to undiagnosed Hashimoto\u27s thyroiditis. Exogenous thyroid hormone replacement therapy rapidly resolved the facial inflammation associated with this type of autoimmune hypothyroidism

Exploring opportunities around climate-smart breeding for future food and nutrition security

There is a 95% chance that warming will exceed 2°C by the end of the century (Raftery et al. 2017). Global crop productivity is projected to fall by 5-10 % per degree of warming (Challinor et al. 2014), with even greater losses likely for some crops in some areas. The challenge of meeting future food demand is increasing, and climate change is already diminishing our ability to adapt through crop breeding (Challinor et al. 2016; Aggarwal et al. 2019). Recent research is suggesting that increases in climate variability are already affecting the number of food-insecure people, and that increasing atmospheric CO2 concentrations may affect the nutrient content of some food staples, with serious implications for food and nutrition security (Smith and Myers 2018). New crop varieties will be needed that can deliver higher yields as well as possessing the ability to withstand heat and greater tolerances for the secondary effects of a warmer world, such as increased pressures from drought, water-logging, pests and diseases, and reduced nutritional quality due to higher levels of CO2. The systems for accelerated delivery of climate-resilient varieties into food producers’ hands need to be massively upgraded (Cramer 2018). Innovative holistic breeding strategies for multiple traits will be needed that embrace the full pipeline from trait discovery to varietal deployment and seed system development

Active and Passive Helicopter Noise Reduction Using the AVINOR/HELINOIR Code Suite

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143085/1/1.C034519.pd

The HELINOIR Aeroacoustic Code and its Application to Active/Passive Helicopter Noise Reduction

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143060/1/6.2017-1179.pd

Comprehensive Numerical Assessment of Rotorcraft Vibration and Noise Control Using Microflaps

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140642/1/1.c033448.pd

G_2 Domain Walls in M-theory

M-theory is considered in its low-energy limit on a G_2 manifold with non-vanishing flux. Using the Killing spinor equations for linear flux, an explicit set of first-order bosonic equations for supersymmetric solutions is found. These solutions describe a warped product of a domain wall in four-dimensional space-time and a deformed G_2 manifold. It is shown how these domain walls arise from the perspective of the associated four-dimensional N=1 effective supergravity theories. We also discuss the inclusion of membrane and M5-brane sources.Comment: 30 pages, Late

Triplanar Model for the Gap and Penetration Depth in YBCO

YBaCuO_7 is a trilayer material with a unit cell consisting of a CuO_2 bilayer with a CuO plane of chains in between. Starting with a model of isolated planes coupled through a transverse matrix element, we consider the possibility of intra as well as interplane pairing within a nearly antiferromagnetic Fermi liquid model. Solutions of a set of three coupled BCS equations for the gap exhibit orthorhombic symmetry with s- as well as d-wave contributions. The temperature dependence and a-b in plane anisotropy of the resulting penetration depth is discussed and compared with experiment.Comment: To appear in Physical Review B1 01Mar97; 12 pages with 10 figures; RevTeX+eps