7,285 research outputs found
Radiation pyrometer for gas turbine blades
A turbine blade temperature measuring system for liquid oxygen turbopumps is reported. The system includes a three mode, two-input optical signal processor, interconnecting cable, and four sensor heads. Two of the heads are aperture type, while the other two are lens type. This system is applicable to a temperature range of 1400 to 2200 F
Why Are Power Couples Increasingly Concentrated in Large Metropolitan Areas
Using census data, Costa and Kahn (QJE, 2000) find that power couples - couples in which both spouses have college degrees - are increasingly likely to be located in the largest metropolitan areas. One explanation for this trend is that college educated couples are more likely to face a co-location problem - the desire to satisfy the career aspirations of both spouses - and therefore are more attracted to large labor markets than are other couples. An alternative explanation is that all college educated individuals, married and unmarried, are attracted to the amenities and high returns to education found in large cities and that as a result, the formation of power couples through marriage of educated singles and additional education is more likely to occur in larger than smaller metropolitan areas. Using the Panel Study of Income Dynamics (PSID), we analyze the dynamic patterns of migration, marriage, divorce and education in relation to city size and find that power couples are not more likely to migrate to the largest cities than part-power couples or power singles. Instead, the location trends are better explained by the higher rate of power couple formation in larger metropolitan areas. Regression analysis suggests that it is only the education of the husband and not the joint education profile of the couple that affects the propensity to migrate to large metropolitan areas.
Family Proximity, Childcare, and Women's Labor Force Attachment
We show that close geographical proximity to mothers or mothers-in-law has a substantial positive effect on the labor supply of married women with young children. We argue that the mechanism through which proximity increases labor supply is the availability of childcare. We interpret availability broadly enough to include not only regular scheduled childcare during work hours but also an insurance aspect of proximity (e.g., a mother or mother-in-law who can provide irregular or unanticipated childcare). Using two large datasets, the National Survey of Families and Households and the public use files of the U.S. Census, we find that the predicted probability of employment and labor force participation is 4-10 percentage points higher for married women with young children living in close proximity to their mothers or their mothers-in-law compared with those living further away.
Proximity and Coresidence of Adult Children and their Parents: Description and Correlates
The ability of family members to engage in intergenerational transfers of hands-on care requires close proximity or coresidence. In this paper we describe and analyze the patterns of proximity and coresidence involving adult children and their mothers using data from the National Survey of Families and Households (NSFH) and the U.S. Census. Although intergenerational coresidence has been declining in the United States, most Americans live within 25 miles of their mothers. In both the raw data and in regression analyses, the most robust predictor of proximity of adult children to their mothers is education. Individuals are less likely to live near their mothers if they have a college degree. Virtually all previous studies have considered coresidence alone, or else treat coresidence as a limiting case of close proximity. We show that this treatment is misleading. We find substantial differences in the correlates of proximity by gender and marital status, indicating the need to model these categories separately. Other demographic variables such as age, race and ethnicity also affect the probability of coresidence and close proximity, but characteristics indicating a current need for transfers (e.g., disability) are not correlated with close proximity.
Recombination lifetimes in gamma-irradiated P-type float zone silicon
Electron decay rate and absorption cross sections for electron holes and recombination in gamma irradiated n-type silico
A brazing process for Cb-1Cr heat receiver tubes Final report
Zirconium-based alloy brazing of internal fins of Cb-1Zr foil to Cb-1Zr heat receiver tube
Application of integral damping for duct assembly vibration suppression Final report
Bending mode vibratory response of supported and sleeved ducts with fatigue and alloy studie
Optimization of duct assemblies for vibration Quarterly progress report, 1 Jul. - 30 Sep. 1968
Theoretical models and experiments on optimization of duct assemblies for vibratio
Radiation effects on lasers Technical report, Jul. 1, 1965 - May 31, 1966
Effects of space radiation on laser
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