A simple model of electron beam initiated dielectric breakdown

A steady state model that describes the internal charge distribution of a planar dielectric sample exposed to a uniform electron beam was developed. The model includes the effects of charge deposition and ionization of the beam, separate trap-modulated mobilities for electrons and holes, electron-hole recombination, and pair production by drifting thermal electrons. If the incident beam current is greater than a certain critical value (which depends on sample thickness as well as other sample properties), the steady state solution is non-physical

The Connecticut Compensation Act

Connecticut is a proverbially conservative State and rarely has been the first to take up innovations. In adopting an act providing compensation for injured workmen, she has had the advantage of the experience of other countries and other American States. More than three decades ago she took the same course in framing a system of reformed procedure and availed herself of the experiments which had gone before. The Workmen\u27s Compensation Act will doubtless require and undergo important amendments before it reaches its final form. As it stands now, it represents some of the best features of the system which have proven themselves practical elsewhere, with changes designed to adapt it to Connecticut needs. The Act went into effect at the beginning of the current year, the commissioners having been appointed three months before and having used the intervening time in determining broad questions of policy, mapping out plans for the administration of the Act and preparing forms, rules and bulletins. The law came as a distinct innovation in Connecticut jurisprudence. It found both the profession and the public unacquainted, not only with its details, but with the underlying conceptions of the system. The work of those concerned in the administration has been naturally, during the earlier months, largely educational in character, consisting in great part in explaining the Act and seeking to place the people of the State in a position to understand its spirit as well as its details

Controlling Lead Exposure During the Process of Cleaning Aviation Spark Plugs

This study examines the process of removing lead bromide from aircraft spark plugs and the health hazards associated with the present method of cleaning the lead bromide accumulation from aviation spark plugs. Aviation maintenance technicians can be inadvertently exposed to lead while cleaning the lead bromide accumulation from the spark plug electrode during scheduled engine maintenance. This study explores controlling the lead bromide particulate matter after it is removed from the spark plug electrode. Various control methods and/or procedural changes that may be employed to control the spread of lead bromide dust throughout the shop environment and the prevention of employee exposure to lead will also be explored

Contracts Exempting Employers from Liability for Negligence

The negligence, real and imaginary, of employers of labor, gives rise to a large proportion of the lawsuits of every industrial community. Such actions are among the contingencies which are expected and in recent years commonly insured against. To avoid the expense of casualty insurance and the risks of not insuring, the wit of the employer has devised various schemes which have from time to time come before the courts. They are intended to furnish a sort of cheap insurance. It is the object of this article to bring in review some of the principal authorities and seek what answer the courts are giving to the question whether the insurance is as effective as it is economical. The simplest way to attain the result desired by the employer is to adopt the scheme of a contract between employer and employee, under which the latter for a consideration, substantial or nominal, expressly waives all right to recover for personal injury

Understanding Interest And Self-Efficacy In The Reading And Writing Of Students With Persisting Specific Learning Disabilities During Middle Childhood And Early Adolescence

Three methodological approaches were applied to understand the role of interest and self-efficacy in reading and/or writing in students without and with persisting specific learning disabilities (SLDs) in literacy. For each approach students in grades 4 to 9 completed a survey in which they rated 10 reading items and 10 writing items on a Scale 1 to 5; all items were the same but domain varied. The first approach applied Principal Component Analysis with Varimax Rotation to a sample that varied in specific kinds of literacy achievement. The second approach applied bidirectional multiple regressions in a sample of students with diagnosed SLDs-WL to (a) predict literacy achievement from ratings on interest and self-efficacy survey items; and (b) predict ratings on interest and self-efficacy survey items from literacy achievement. The third approach correlated ratings on the surveys with BOLD activation on an fMRI word reading/spelling task in a brain region associated with approach/avoidance and affect in a sample with diagnosed SLDs-WL. The first approach identified two components for the reading items (each correlated differently with reading skills) and two components for the writing items (each correlated differently with writing skills), but the components were not the same for both domains. Multiple regressions supported predicting interest and self-efficacy ratings from current reading achievement, rather than predicting reading achievement from interest and self-efficacy ratings, but also bidirectional relationships between interest or self-efficacy in writing and writing achievement. The third approach found negative correlations with amygdala connectivity for 2 reading items, but 5 positive and 2 negative correlations with amygdala connectivity for writing items; negative correlations may reflect avoidance and positive correlations approach. Collectively results show the relevance and domain-specificity of interest and self-efficacy in reading and writing for students with persisting SLDs in literacy

Detection of Lead in the Carbon-Rich, Very Metal-Poor Star LP625-44: A Strong Constraint on s-Process Nucleosynthesis at Low Metallicity

We report the detection of the Pb I 4057.8A line in the very metal-poor ([Fe/H]=-2.7), carbon-rich star, LP625-44. We determine the abundance of Pb ([Pb/Fe] = 2.65) and 15 other neutron-capture elements. The abundance pattern between Ba and Pb agrees well with a scaled solar system s-process component, while the lighter elements (Sr-Zr) are less abundant than Ba. The enhancement of s-process elements is interpreted as a result of mass transfer in a binary system from a previous AGB companion, an interpretation strongly supported by radial velocity variations of this system. The detection of Pb makes it possible, for the first time, to compare model predictions of s-process nucleosynthesis in AGB stars with observations of elements between Sr and Pb. The Pb abundance is significantly lower than the prediction of recent models (e.g., Gallino et al. 1998), which succeeded in explaining the metallicity dependence of the abundance ratios of light s-elements (Sr-Zr) to heavy ones (Ba-Dy) found in previously observed s-process-enhanced stars. This suggests that one should either (a) reconsider the underlying assumptions concerning the 13C-rich s-processing site (13C-pocket) in the present models, or (b) investigate alternative sites of s-process nucleosynthesis in very metal-poor AGB stars.Comment: 10 pages, 3 figures, Astrophysical Journal Letters, in pres