Reflections on Centaur Upper Stage Integration by the NASA Lewis (Glenn) Research Center

The NASA Glenn (then Lewis) Research Center (GRC) led several expendable launch vehicle (ELV) projects from 1963 to 1998, most notably the Centaur upper stage. These major, comprehensive projects included system management, system development, integration (both payload and stage), and launch operations. The integration role that GRC pioneered was truly unique and highly successful. Its philosophy, scope, and content were not just invaluable to the missions and vehicles it supported, but also had significant Agencywide benefits. An overview of the NASA Lewis Research Center (now the NASA Glenn Research Center) philosophy on ELV integration is provided, focusing on Atlas/Centaur, Titan/Centaur, and Shuttle/Centaur vehicles and programs. The necessity of having a stable, highly technically competent in-house staff is discussed. Significant depth of technical penetration of contractor work is another critical component. Functioning as a cohesive team was more than a concept: GRC senior management, NASA Headquarters, contractors, payload users, and all staff worked together. The scope, content, and history of launch vehicle integration at GRC are broadly discussed. Payload integration is compared to stage development integration in terms of engineering and organization. Finally, the transition from buying launch vehicles to buying launch services is discussed, and thoughts on future possibilities of employing the successful GRC experience in integrating ELV systems like Centaur are explored

Car wash water recycling system

The high rate of transportation and vehicle washing centers led to an increase in water consumption. When the water consumption increase, the amount of wastewater discharged and the cost of utility will also increase. Only the right technique used for washing the vehicles can minimize the amount of water consumption. Conservation of water will not only save the water supply, but it will also help in financial savings. Recycling and reusing the water from the car wash means collecting, processing, and treating the contaminated water to remove the dirt and contaminants and using the treated water again for car washing. As cars body always stained with dirt and dust while driving, some dirt such as small stones might stuck and penetrate into the wheels and caused major damage. Thus, a regular car wash usually is needed for every vehicle to avoid this problem. Moreover, getting a regular car wash can also improve car performance. Hence, periodically car washing is one of the best ways to preserve and maintain the performance of vehicles

Is housing overvalued?

This paper examines whether it is more expensive to own a house or to rent. The paper assesses houses as ‘overvalued’ if home buyers pay too much, in the sense that they would be better off renting than buying. This involves comparing the financial cost of renting a home with the cost of owning a similar dwelling, where the latter depends on the purchase price, interest rates, repairs, council rates and so on. The paper also briefly examines non-financial costs but find these are small, on average. This paper finds if real house prices grow at their historical average pace, then owning a home is about as expensive as renting. If prices grow more slowly, as some forecasters predict, the framework used in this paper suggests that the average home buyer would be financially better off renting. House prices are decomposed into contributions from rents, interest rates and expected capital gains, which may help policymakers in the detection of housing bubbles. Recent data do not show signs of a bubble

Sunk Investments Lead to Unpredictable Prices

We study transactions that require investments before trading in a competitive market, when forward contracts fixing the transaction price are absent. We show that, despite the market being perfectly competitive and subject to arbitrarily little uncertainty, the inability to jointly determine investment levels and prices may make it impossible for buyers and sellers to predict the prices at which they will trade, leading to inefficient levels of investment and trade.General equilibrium, sunspots, incomplete markets

Sunk Investments Lead to Unpredictable Prices (Second Version)

We study transactions that require investments before trading in a competitive market, when forward contracts fixing the transaction price are absent. We show that, despite the market being perfectly competitive and subject to arbitrarily little uncertainty, the inability to jointly determine investment levels and prices may make it impossible for buyers and sellers to predict the prices at which they will trade, leading to inefficient levels of investment and trade.Sunk investments, inefficient investments, sunspots, random prices.

Consumer shopping behavior: how much do consumers save?

This paper documents the potential and actual savings that consumers realize from four particular types of purchasing behavior: purchasing on sale; buying in bulk (at a lower per unit price); buying generic brands; and choosing outlets. How much can and do households save through each of these behaviors? How do these patterns vary with consumer demographics? We use data collected by a marketing firm on all food purchases brought into the home for a large, nationally representative sample of U.K. households in 2006. We are interested in how consumer choice affects the measurement of price changes. In particular, a standard price index based on a fixed basket of goods will overstate the rise in the true cost of living because it does not properly consider sales and bulk purchasing. According to our measures, the extent of this bias might be of the same or even greater magnitude than the better-known substitution and outlet biases

“The Impact of Housing Market Institutions on Labour Mobility: A European Cross-Country Comparison.” ENEPRI Working Paper No. 54, July 2007

This paper examines the effects of housing market institutions on labour mobility. The authors construct durations for individuals leaving their current job for a different job, becoming unemployed or leaving the labour market, from a sample of households from 14 European countries in 1994-2001. This data are then merged with country-specific housing market institutions, such as transaction taxes, and language and religion diversity. Similar to previous studies, estimated hazards indicate that home-ownership reduces job-to-job mobility as well as the probability to become unemployed or economically inactive on an individual level. However, a comparison between countries reveals that countries with high levels of home-ownership rates also have high levels of unemployment. Therefore, this paper is able to reconcile the seemingly contrasting empirical results from both the macroeconomic and the microeconomic level