Labor turnover of gas and water meter readers as related to a standarized pre-employment test battery

Statement of the Problem: 1. To determine what factors as measured by standardized tests, used in employee selection, are related to the length of service of gas and water meter readers. 2. To devise a method of prediction to be validated on a separate sample of employed meter readers

Heats of Solution of Silver Halides in Liquid Ammonia

It was the hope of the experimenters to make use of one of the advantages of liquid ammonia, that of the solubility of metallic sodium to give a free electron, to find the heat of reduction of the silver ion to the metallic state

The Urban Renewal Movement in Omaha, 1954-1970

By 1954, the year President Dwight D. Eisenhower signed a national housing act, one hundred years had passed since a group of Iowa businessmen crossed the Missouri River and surveyed Omaha City. The townsite formed the only metropolis in Nebraska at the midpoint of the twentieth century. Suffering from age and neglect, sections in and around the downtown core of Omaha became the object of a controversial crusade by civic leaders. A variety of business, labor, professional and government interests accepted the Eisenhower legislation as a practical way to rebuild the deteriorated areas. The law contained a slum clearance scheme called urban renewal that provided federal funds to municipal governments, which could hire private contractors to redevelop an area in compliance with a federally approved plan. The urban renewal concept met stiff, angry opposition from the Omaha public. A majority of the voters. believing that it trespassed on individual property rights, rejected the program. The vocal opponents expounded the argument that the renewal method misused the power of eminent domain by reselling seized property to private developers. Proponents stressed that numerous state courts upheld the law as beneficial to the common good, but they failed to arouse a community spirit supportive of redevelopment. Urban renewal frightened many Omahans, who distrusted the complicated program so avidly pursued by business and labor organizations

Financial characteristics of merged firms : a multivariant analysis / BEBR No. 60

Includes bibliographical references

The stability of immiscible viscous fingering in Hele-Shaw cells with spatially varying permeability

In this paper, we investigate the stability of immiscible viscous fingering in Hele-Shaw cells with spatially varying permeability, across a range of capillary numbers. We utilise a coupled boundary element - radial basis function (BE –RBF) numerical method that adapts and moves with the growing interface, providing an efficient, high accuracy scheme to track the interfacial displacement of immiscible fluids. By comparing the interfacial evolution and growth rate in varying permeability cells to that in uniform cells, we can assess the relative stability of the perturbations as a consequence of the variable permeability. Numerical experiments in Hele-Shaw cells with gradually varying permeability highlight 3 aperture effects that control the interfacial stability: (1) Gradients in the capillary pressure (2) Local changes in fluid mobility (3) Variation in the viscous pressure gradient. In low capillary number regimes, we find that aperture effect 1 and 2 dominate, which (relatively) stabilise interfacial perturbations in converging geometries and destabilise perturbations in diverging geometries. In high capillary number regimes, aperture effect 3 dominates meaning the relative stability transitions; the interface is destabilised in converging cells and stabilised in diverging cells. We find an upper bound critical capillary number Cagt at which the relative stability transitions in our gradually varying cell as 1000<Cagt<1250, which is independent of both α and ϵ0. This result is much lower than the value of Cagt=9139 predicted by linear stability theory, due to significant non-linear perturbation growth. This transition links the results found in previous works performed at low and high capillary numbers, providing new insight into the viscous fingering instability in variable permeability cells. To conclude, we present simulations in Hele-Shaw cells with large geometric heterogeneities and anisotropy, in order to demonstrate the significant fluid re-distribution that can occur due to localised variations in cell permeability. Using periodic permeability distributions, we show the significant re-distribution of fluid that can occur due to large capillary pressure gradients in the capillary limit, and the channelling of flow that can occur in the viscous limit along anisotropic features

Regional Climate Trends and Scenarios for the U.S. National Climate Assessment Part 4. Climate of the U.S. Great Plains

This document is one of series of regional climate descriptions designed to provide input that can be used in the development of the National Climate Assessment (NCA). As part of a sustained assessment approach, it is intended that these documents will be updated as new and well-vetted model results are available and as new climate scenario needs become clear. It is also hoped that these documents (and associated data and resources) are of direct benefit to decision makers and communities seeking to use this information in developing adaptation plans. There are nine reports in this series, one each for eight regions defined by the NCA, and one for the contiguous U.S. The eight NCA regions are the Northeast, Southeast, Midwest, Great Plains, Northwest, Southwest, Alaska, and Hawai‘i/Pacific Islands. These documents include a description of the observed historical climate conditions for each region and a set of climate scenarios as plausible futures – these components are described in more detail below. While the datasets and simulations in these regional climate documents are not, by themselves, new, (they have been previously published in various sources), these documents represent a more complete and targeted synthesis of historical and plausible future climate conditions around the specific regions of the NCA. There are two components of these descriptions. One component is a description of the historical climate conditions in the region. The other component is a description of the climate conditions associated with two future pathways of greenhouse gas emissions

Speciation in Western North America: Lomatium as an Example of Diversification and Convergent Evolution

Species delimitations and understanding the processes that drive speciation are essential to nearly all aspects of human endeavor. Determining species boundaries traditionally used morphology. Phylogenetic analyses based on DNA sequence data provide a means to resolve species boundaries, as well as test hypotheses regarding the evolutionary processes. Numerous species radiations have occurred in Western North America. Among these are several plant groups such as Astragalus, Artemisia, and Lomatium. Recent phylogenetic analyses of Lomatium and related genera have demonstrated that many of the morphological characters used to delimit taxa have arisen multiple times and that most taxa are para- or polyphyletic. Here we examine one of the clades recovered in the Lomatium group of taxa that includes Lomatium triternatum and L. grayi. The several subspecific taxa of L. triternatum have not been recovered as monophyletic and L. grayi has a widespread habitat distribution that may indicate cryptic speciation. Previous analyses have not fully resolved phylogenetic relationships with strong support. In the present study we sample an additional four loci (three chloroplast and one nuclear ribosomal) to improve the support for evolutionary relationships across this clade, resolve species boundaries, and test hypotheses on the evolution of morphological traits

Peroxide-cured HFP boosts cure rate, demolding

Executive summary Fluoroelastomers having a monomer composition of tetrafluoroethylene (TFE), hexafluoropropylene (HFP) and vinylidene fluoride (VF2) with an incorporated cure site monomer that allows peroxide crosslinking have grown in commercial significance in the past 20 years since the introduction of Viton GF in 1980. While these FKM terpolymers show improved water, steam and acid resistance, the need to peroxide crosslink them has caused processing problems such as mold sticking and poor hot tear resistance. This paper will introduce a new generation of peroxide-cured HFP-containing fluoroelastomers, which use a new, unique improved cure site monomer system. These ICSM containing products give much faster cure rates, low mold fouling and improved hot-demolding properties. In addition, they provide improved compression set resistance, even when not postcured, and enhanced aqueous media resistance. Processing and end-use data will highlight the utility of these new type fluoroelastomers. TECHNICAL NOTEBOOK Edited by Harold Herzlich Fluoroelastomer terpolymers having a structure of hexafluoroproplyene (HFP), tetrafluoroethylene (TFE) and vinylidene fluoride (VF2) have been used since the 1960s in a variety of industrial and automotive applications. The general chemical structure of these polymers is shown in In the mid-1970s a breakthrough in cure systems became available to the fluoroelastomer chemist, an FKM terpolymer with incorporated cure site monomer (CSM) that was sensitive to a peroxide/coagent cure system These peroxide-cured types of FKM were introduced at the San Francisco Rubber Division/ACS meeting by Finlay, MacLachlan and Hallenbeck1,2 in 1976, and in 1980, Bauerle and Finlay3 introduced an improved ~70-percent fluorine version of this type of FKM called Viton GF. Later, 68-percent fluorine versions of these elastomers called GBL900 and GBL200 were introduced by Tabb and Stevens4 at the Los Angeles Rubber Division/ACS meeting in 1985. These new peroxide-cured types of fluoroelastomer had several advantages in end-use properties, specifically in the area of fluids resistance. The peroxidecured polymers do not depend on strong metal bases such as magnesium oxide to dehydrohalogenate the backbone at the VF2-HPF site to initiate a double bond for the crosslinking reaction, rather they crosslink through a cure site monomer by use of a coagent that is activated by a peroxide. These peroxide-cured FKMs are known to have improved water, steam, acid and amine additive resistance when compared to conventional bisphenol-cured types of fluoroelastomers. While the end-use properties of peroxide-cured FKM are quite impressive, the processability of compounds suffers from the use of this cure system. Mold sticking and reduced hot tear strength are two problems that can be observed when processing peroxide-cured FKM. These problems led to more production scrap and higher part costs for peroxidecured FKMs