Chemical analysis of atmospheric dust.

The chemical analysis of atmospheric dust is of interest to two major groups, namely—the workers in industrial hygiene and the workers in the air cleaning and ventilating industries. The industrial hygienists, who are concerned with the prevention of occupational diseases and the maintenance of the health of industrial workers on a high level, are mainly interested in the concentration of irritating dusts and allergy-producing dusts that would obviously affect the health or comfort of industrial workers. Their interest, as one would expect, is in atmospheric dust of small particle sizes (10 microns and smaller), and in gaseous substances which they believe to be the most important from a health standpoint. The air cleaning and ventilating industries face an additional aspect of the problem of air pollution. Their problem is to devise instruments for capturing and removing solid matter from a stream of air. This solid matter includes fibrous material, such as lint, particles of earth, carbon, sand, ash, pollen, etc. Probably the most abundant of these solid particles is carbon, which is the chief offender in soiling. The removing of this very undesirable property of soiling from the atmosphere is equally as important as removing materials that are harmful to health. The problem of control soiling is unique with the air cleaning and ventilating industries and has led to the development of considerable testing technology for its evaluation. Experience in these industries has shown that it is not only necessary to know the type of dust, its concentration and its chemical composition but also the percentage of soiling material present in the atmosphere, if a synthetic testing material is to be created which will give a true efficiency rating for a filter in the laboratory. Studies indicate that there are variations in opinions as to what per cent carbon black (Free Carbon) a synthetic testing material of this nature should contain. The results of the analysis presented in this paper should help to clarify this problem of testing filters under conditions similar to those of actual field operations. The chemical analysis of atmospheric dust is a complex problem. The complexity arises not only from the diversity of elements and compounds present in each local section of the earth’s crust but also from the various local artificial dust produced by man. Perhaps just as important as the concentration of these elements or compounds is the variety of physical forms these materials may take. The methods applied to the analysis of a dust sample depends primarily upon its physical form, and how much of a sample has been collected, and how much contaminant is present in the sample. These variations in the collected samples have led to the development of various methods of analysis. A preliminary survey of this analytical problem revealed that the gravimetric method was most suitable for these analyses. This research program has been devoted to (1) developing a suitable analytical method for the determination of free carbon in atmospheric dust (2) analyzing thirty-seven samples of atmospheric dirt, collected in various United States cities by sales representatives of the American Air Filter Company, during the first four or five months of 1949, for free carbon, ash, mixed oxides, and silica, (3) adapting the developed analytical method for the determination of free carbon in atmospheric dust to a semimicro scale, (4) analyzing daily and weekly samples collected with electrostatic dust samplers in order to determine what the soiling conditions are in a given location at a given time. For clearness to all readers, the term free carbon is uncombined carbon in any of its various forms and term ash refers to the product left after a sample has been burned in the laboratory under controlled conditions. This latter term should not be confused with fly ash

Decision Inputs of Administrative Law Judges

Administrative Law Judges (ALJs) play an important role in the Social Security Administration (SSA) as they hear appeals from individuals who have been denied Social Security Disability Insurance (SSDI) benefits. As a result, the decisions of these judges have important effects on both individual welfare and government finances, especially given that the SSDI trust fund is expected to go bankrupt within the next few years. This paper examines how disability dispositions, decisions, and award rates by ALJs in the SSA vary according to factors such as gender, tenure with the SSA, age, general experience in the legal profession, and salary. The data, which span the years 2005-2011, are obtained from the SSA’s Office of Disability and Adjudication Review (ODAR), which publicly reports statistics such as the number of appeals heard and the percentage of favorable decisions by each judge, along with internet searches to obtain information on the personal attributes of the judges. Understanding the factors affecting the decisions of these judges could be useful for identifying fruitful avenues for the SSA to control spending through this program, and more generally could provide insight on how the attributes of highly educated professional workers affect their work output

The status of economics in the high schools of New England.

Thesis (Ed.M.)--Boston Universit

Investigating the Relationship between Telecommuting and Career Harm

This project aims to examine how the use of flexible work arrangements influence career earnings and promotions at work. The study will focus on the flexible work arrangement of telecommuting because of telecommuting’s surge in popularity over the last decade and the need for more studies assessing telecommuting’s effects. Research shows many benefits are associated with flexible work arrangements like job satisfaction, increased productivity, decreased turnover, and organizational savings. Flexible work arrangements, however, have been shown to potentially impede wage growth and other career advancing opportunities (e.g. promotions). For example, the use of FMLA policies as a flexible work arrangement and its impact on wage growth is commonly referred to as a parenthood penalty. While telecommuting has become more common in the workplace, people are still reluctant to engage in this flexible work practice for several reasons with the potential for career harm being a major concern. However, there is limited research of the impact telecommuting has on career harm in relation to salary and promotions. A major hurdle for researchers assessing the impact of telecommuting on career harm revolves around data collection methods and proper documentation of telecommuting practices by organizations. Ideally, an entity or researcher would gather longitudinal data from respondents over several years to compare those who engage in telecommuting and those who don’t. Additionally, many organizations have yet to maintain detailed records of an employee’s use of telecommuting practices in their own organization. Consequently, the manager is often responsible for monitoring an employee’s performance and it is usually up to the manager’s discretion on whether or not an employee will be allowed to telecommute. This decision by the manager adds another variable to the relationship between telecommuting and career harm, manager support. The existing literature comparing telecommuters to non-telecommuters conflict. Some reports show the positive impact telecommuting has on career earnings, while many others show career dampening results. The goal of this study is to assess the relationship between telecommuting and career harm by gathering years of historical data from respondents concerning their salary, promotions, intensity of telecommuting, manager support, organization characteristics, type of job, and career ambition. The data will be analyzed through fixed effect regression and mediation analyses on manager support and career ambition

HST imaging and Keck Spectroscopy of z~6 I-band Drop-Out Galaxies in the ACS GOODS Fields

We measure the surface density of i'-band dropout galaxies at z~6 through wide field HST/ACS imaging and ultra-deep Keck/DEIMOS spectroscopy. Using deep HST/ACS SDSS-i' (F775W) and SDSS-z' (F850LP) imaging from GOODS-N (200 arcmin^2), we identify 9 i'-drops satisfying an (i'-z')_AB>1.5 selection criterion to a depth of z'_AB=25.6 (corresponding to L*_UV at z~3-4). We use HK' imaging data to improve the fidelity of our sample, discriminating against lower redshift red galaxies and cool Galactic stars. Three i'-drops are consistent with M/L/T dwarf stars. We present ultra-deep Keck/DEIMOS spectroscopy of 10 objects from our combined GOODS-N and GOODS-S i'-drop sample. We detect Lyman-alpha emission at z=5.83 from one object in the GOODS-S field, which lies only 8arcmin away (i.e. 3Mpc/h_70) from the z=5.78 object already confirmed by Bunker et al. (2003). One possible Lyman-alpha emitter at z=6.24 is found in the GOODS-N field (although identification of this spatially-offset emission line is ambiguous). Using the rest-frame UV continuum from our 6 candidate z~6 galaxies from the GOODS-N field, we determine a lower limit to the unobscured volume-averaged global star formation rate at z~6 of (5.4+/-2.2)x10^-4 h_70 M_sun/yr/Mpc^3. We find that the cosmic star formation density in galaxies with unobscured star formation rates 15M_sun/yr/h_70^2 falls by a factor of 8 between z~3 and z~6. Hence the luminosity function of LBGs must evolve in this redshift interval: a constant integrated star formation density at $z>3$ requires a much steeper faint-end slope, or a brighter characteristic luminosity. This result is in agreement with our previous measurement from the Chandra Deep Field South (Stanway et al. 2003), indicating that cosmic variance is not a dominant source of uncertainty.Comment: to appear in ApJ; replaced with accepted versio