Prediction of force coefficients for labyrinth seals

The development of a linear model for the prediction of labyrinth seal forces and on its comparison to available stiffness data is presented. A discussion of the relevance of fluid damping forces and the preliminary stages of a program to obtain data on these forces are examined. Fluid-dynamic forces arising from nonuniform pressure patterns in labyrinth seal glands are known to be potentially destablizing in high power turbomachinery. A well documented case in point is that of the space Shuttle Main Engine turbopumps. Seal forces are also an important factor for the stability of shrouded turbines, acting in that case in conjunction with the effects of blade-tip clearance variations

Como Lo Hicimos: The Success of Latino/a Businesses in Michigan

Using data from the same oral history interviews used by Coronado and Martinez (2018), this study describes the success of some Latino businesses operating in Michigan. It is based on interviews with 32 Latino and Latina business owners (LBOs) conducted by researchers at the Julian Samora Research Institute (JSRI) at Michigan State University from 2011 to 2012 in three Michigan cities: Saginaw, Lansing, and Metro Detroit. This study describes the ways and means by which these business owners started their businesses and the success and possible expansion of their activities at the time of the interviews. Almost all had humble start-up operations, relied on their own or family savings, had relatives who owned or operated a business, lacked access to formal financial markets, and had limited knowledge about government programs supporting small businesses. Success was based on hard work and persistence, the pursuit of opportunities, and the use of technology. Most give back to their communities and have expansion plans, either by securing government funds or bank loans

Funding Constraints for Latino Business Start-Ups

This study focusses on the high growth of Latino-owned businesses (LOBs) in the United States during the last two decades and the constraints these businesses face during their start-up and development stages. During this period, the number of LOBs increased faster than businesses owned by other racial and ethnic groups. The study also addresses the following aspects of Latino business ownership: 1) the main reasons U.S. Latinos decide to become business owners; 2) their reluctance to seek loans from formal financial markets; 3) internal and external factors that limit Latino business owner participation in financial markets, 4) and the internal and external factors that banks and other financial institutions face when working with Latino businesspeople. We found important gaps in access to credit between LOBs and two comparison groups: i) Equally-Latino & non-Latino firms and ii) White-owned businesses

The stellar, molecular gas and dust content of the host galaxies of two z~2.8 dust obscured quasars

We present optical through radio observations of the host galaxies of two dust obscured, luminous quasars selected in the mid-infrared, at z=2.62 and z=2.99, including a search for CO emission. Our limits on the CO luminosities are consistent with these objects having masses of molecular gas <~10^10 solar masses, several times less than those of luminous submillimeter-detected galaxies (SMGs) at comparable redshifts. Their near-infrared spectral energy distributions, however, imply that these galaxies have high stellar masses (~10^11-12 solar masses). The relatively small reservoirs of molecular gas and low dust masses are consistent with them being relatively mature systems at high-z.Comment: AJ, in pres

Short pulse generation in solid state lasers by a novel passive technique

Includes bibliographical references (page 216).A novel passive Q-switching technique based on self-focusing is studied theoretically and experimentally. In this paper we present results obtained with a simple aberrationless gaussian model that describes the short pulse generation dynamics for different cavity configurations and different nonlinear characteristics of the focusing medium. Experimental results are also presented that are in good agreement with the predictions of the theoretical model. Preliminary results in ultrashort pulse generation are also presented