MSFC hot air collectors

A description of the hot air collector is given that includes a history of development, a history of the materials development, and a program summary. The major portion of the solar energy system cost is the collector. Since the collector is the heart of the system and the most costly subsystem, reducing the cost of producing collectors in large quantities is a major goal. This solar collector is designed to heat air and/or water cheaply and efficiently through the use of solar energy

Investing under model uncertainty: decision based evaluation of exchange rate forecasts in the US, UK and Japan

We evaluate the forecast performance of a range of theory-based and atheoretical models explaining exchange rates in the US, UK and Japan. A decision-making environment is fully described for an investor who optimally allocates portfolio shares to domestic and foreign assets. Methods necessary to compute and use forecasts in this context are proposed, including the means of combining density forecasts to deal with model uncertainty. An out-of-sample forecast evaluation exercise is described using both statistical criteria and decision-based criteria. The theory-based models are found to perform relatively well when their forecasts are judged by their economic value

Measuring the natural output gap using actual and expected output data

An output gap measure is suggested based on the Beveridge-Nelson decomposition of output using a vector-autoregressive model that includes data on actual output and on expected output obtained from surveys. The paper explains the advantages of using survey data in business cycle analysis and the gap is provided economic meaning by relating it to the natural level of output defined in Dynamic Stochastic General Equilibrium models. The measure is applied to quarterly US data over the period 1970q1-2007q4 and the resultant gap estimates are shown to have sensible statistical properties and perform well in explaining inflation in estimates of New Keynesian Phillips curves

Efficient Computation of CMB anisotropies in closed FRW models

We implement the efficient line of sight method to calculate the anisotropy and polarization of the cosmic microwave background for scalar and tensor modes in almost-Friedmann-Robertson-Walker models with positive spatial curvature. We present new results for the polarization power spectra in such models.Comment: 4 pages, 1 figure. Corrected/updated references. Accepted by ApJ. For the F90 source code see http://www.mrao.cam.ac.uk/~aml1005/cmb

Real-time representations of the output gap

Methods are described for the appropriate use of data obtained and analysed in real time to represent the output gap. The methods employ cointegrating VAR techniques to model real-time measures and realizations of output series jointly. The model is used to mitigate the impact of data revisions; to generate appropriate forecasts that can deliver economically meaningful output trends and that can take into account the end-of-sample problems encountered in measuring these trends; and to calculate probability forecasts that convey in a clear way the uncertainties associated with the gap measures. The methods are applied to data for the United States 1965q4–2004q4, and the improvements over standard methods are illustrated

Low-cost hot-air solar collector

System has only three components per cell. Cell parts are fabricated from readily available materials and, following a construction procedure which requires use of only simple handtools, can be mounted in place by one person

Self-regenerating desiccant system

Compact system uses inherent diurnal cyclic airflow in system and energy of sun as drying heat. System requires no power for operation, has no moving parts to wear out, requires no blowers or manifolds, and is relatively inexpensive to produce

Estimating the Ability of Gamblers to Detect Differences in the Payback Percentages of Reel Slot Machines: A Closer Look at the Slot Player Experience

The results of play on 60 different computer simulated reel slots challenge the widely held theory that frequent slot players are able to detect changes in a slot machine\u27s house advantage as slight as 1 to 2%. These findings affect the formulation of critical and capital-intensive customer retention strategies and brand positioning campaigns within the gaming industry. An overwhelming majority of 10,000 virtual players were not able to reject the hypothesis of equal payback percentages after playing both a 3% game and a 12% game (i.e., a 400% increase in the house advantage). This result held across three levels of pay table variance and five levels of trials or spins. The differences in house advantages examined herein ranged from 33% to 400%, across the various 2-game comparisons. The results also fail to support those who argue or fear that frequent slot players are able to detect changes in the house advantage over time. Profits from slot operations are critical to the success of most casino resorts, making this research into the slot player experience a valuable contribution to both the literature and casino management