A numerical study on aerodynamic resonance in transonic separated flow

An ongoing numerical investigation of unsteady shock/boundary layer interaction on a 2-d supercritical airfoil in transonic flow is presented. Initially, the finitevolume URANS solver DLR-TAU is used to simulate self-sustained periodic shock oscillations well known as shock buffet. Next, emphasis is put on the fixed-point stability of the steady flow field below the shock buffet onset. Therefore the flow is perturbed in time with small sinusoidal deflections of the airfoil geometry and random impulses. With increasing angle of attack the mean flow is shown to develop a damped aerodynamic resonance, that degenerates finally towards self-amplification. The occurrence of the aerodynamic resonance is closely related to the development of shock-induced separation, accompanied by quasi-steady inverse shock motion

Aeroelastic analysis of a troposkien-type wind turbine blade

The linear aeroelastic equations for one curved blade of a vertical axis wind turbine in state vector form are presented. The method is based on a simple integrating matrix scheme together with the transfer matrix idea. The method is proposed as a convenient way of solving the associated eigenvalue problem for general support conditions

Jahn-Teller like origin of the tetragonal distortion in disordered Fe-Pd magnetic shape memory alloys

The electronic structure and magnetic properties of disordered Fe$_{x}$Pd$_{100-x}$ alloys $(50 < x < 85)$ are investigated in the framework of density functional theory using the full potential local orbital method (FPLO). Disorder is treated in the coherent potential approximation (CPA). Our calculations explain the experimental magnetization data. The origin of the tetragonal distortion in the Fe-Pd magnetic shape memory alloys is found to be a Jahn-Teller like effect which allows the system to reduce its band energy in a narrow composition range. Prospects for an optimization of the alloys' properties by adding third elements are discussed

Development of a Thermal Management System for Electrified Aircraft

This paper describes the development and optimization of a conceptual thermal management system for electrified aircraft. Here, a vertical takeoff and landing (VTOL) vehicle is analyzed with the following electrically sourced heat loads considered: motors, generators, rectifiers, and inverters. The vehicle will employ liquid-cooling techniques in order to acquire, transport, and reject waste heat from the vehicle. The purpose of this paper is to threefold: 1) Present a potential modeling framework for system level thermal management system simulation, 2) Analyze typical system characteristics, and 3) Perform optimization on a system developed for a specific vehicle to minimize weight gain, power utilization, and drag. Additionally, the paper will study the design process, specifically investigating the differences between steady state and transient sizing, comparing simulation techniques with a lower fidelity option and quantifying expected error

Concise review : increasing the validity of cerebrovascular disease models and experimental methods for translational stem cell research

Interspecies differences, anatomical and physiological aspects, as wells as simplified study designs contribute to an overestimation of treatment effects and limit the transferability of experimental results into clinical applications. Confounders of cell therapies for cerebrovascular disorders (CVD) include common CVD comorbidities, frequent medications potentially affecting endogenous and transplanted stem cells, as well as age‐ and immune‐system–related effects. All those can contribute to a substantial modeling bias, ultimately limiting the prospective quality of preclinical research programs regarding the clinical value of a particular cell therapy. In this review, we discuss the nature and impact of most relevant confounders. We provide suggestions on how they can be considered to enhance the validity of CVD models in stem cell research. Acknowledging substantial and sometimes surprising effects of housing conditions, chronobiology, and intersex differences will further augment the translational value of animal models. We finally discuss options for the implementation of high‐quality functional and imaging readout protocols. Altogether, this might help to gain a more holistic picture about the therapeutic impact of a particular cell therapy for CVD, but also on potential side and off‐site effects of the intervention

Farmers Markets: Producers Characteristics and Status of Their Businesses

The purpose of this study was to provide an overview of the attributes of producers who participate in farmers’ markets and to examine different aspects of their operations. In addition to demographics, the characteristics explored in this report include farm size, acreage grown, wholesale and retail activities, location, and personnel employed. Data related to business development, ownership status, days of operation, products sold, marketing and organic production was also collected. The results show that the majority of New Jersey growers who retail through farmers’ markets began this type of activity since 1990 and while their businesses were still in a state of growth. However, the average number of acres planted and workers employed characterized farmers’ markets as small scale operations. The income from these facilities represented, in general, less than 40 percent of the total retail gross sales. Most producers indicated that they were satisfied with the profit margin obtained. Farmers usually attended 1 market per day and traveled an average of 54 miles daily. In particular, farmers chose farmers’ markets as a retail channel because they could obtain higher prices, target a greater volume of people, interact with customers and lower overhead costs. Tomatoes, corn, herbs, peaches, flowers, apples and greens were the most important farm products sold based on dollar value. Although the majority of the farmers sold value-added products, only 23 percent of those surveyed offered organic produce. Prices were usually determined by comparison with chain stores or based on cost accounting, market reports or experience. In general, participants believed that their farmers’ market operations would continue to expand over the next five years. The descriptive results presented in this report help identify the characteristics that contribute towards growers’ participation in the farmers’ markets and the factors that make these operations a viable marketing alternative. These findings may be especially useful for those in charge of the planning and coordination of farmers’ markets.Agribusiness, Marketing,

A review of behavioural and management effects in mutual fund performance

This paper surveys and critically evaluates the literature on the role of management effects and fund characteristics in mutual fund performance. First, a brief overview of performance measures is provided. Second, empirical findings on the predictive power of fund characteristics in explaining future returns are discussed. Third, the paper reviews the literature on fund manager behavioural biases and the impact these have on risk taking and returns. Finally, the impact of organizational structure, governance and strategy on both fund risk taking and future performance is examined. While a number of surveys on mutual fund performance are available, these have not focused on the role of manager behavioural biases, manager characteristics and fund management strategic behavior on fund performance and risk taking. This review is an attempt to fill this gap. Empirical results indicate that finding successful funds ex-ante is extremely difficult, if not impossible. In contrast, there is strong evidence that poor performance persists for many of the prior "loser fractile" portfolios of funds. A number of manager behavioural biases are prevalent in the mutual fund industry and they generally detract from returns