125 research outputs found
A Note on the Flexural Properties of Bark Board
Bending properties of particleboards made from soft maple, red oak, white oak, black cherry, beech, and yellow-poplar bark were obtained and compared with the specimen's density and thickness. Regression analyses indicated that the bending properties depend not only on species but also on density and/or specimen thickness. This dependence was not consistent among species
The Effect of Species and Substrate Density on the Flexural Properties of Epoxy-Impregnated Barkboard
Bark from red oak, yellow-poplar, soft maple, and beech was individually mixed with 6% (by weight) powdered phenolic resin and pressed into boards having nominal densities of 40, 50, 60, and 70 lb/ft3 (0.64, 0.80, 0.96, and 1.12 g/cm3). Half of these boards were used as controls and half were impregnated with a solution of 100 parts by weight of epoxy resin, 25 parts styrene oxide, and 12.06 parts N,N-diethyl-1, 3-propanediamine. Polymer retention was found to be linearly related to the substrate density and was somewhat dependent upon the species of bark. The impregnation process resulted in dramatic changes in the flexural properties of the barkboard. Increases in MOR of 3.0- to 4.0-fold and in MOE of 2.6- and 3.6-fold were observed over control values, with the largest improvements occurring in the red oak specimens. In contrast to the control specimens, MOR and MOE values for the epoxy-impregnated specimens were not well correlated. In addition, correlations of MOR with the substrate density and polymer mass loading were generally low or varied greatly with bark species. MOE correlations were notably higher, but variable
Magnetic Property Changes in various Structural Steels Due to Irradiation
Nondestructive evaluation in nuclear power plants has been a growing concern for electric utility operators over the past decade 1. Many plants are operating beyond their original design lives primarily through intermittent replacement of individual components as necessary. It is critically important for the NDE field to develop technology that can evaluate the life expectancy of components in these plants, such as steam boiler pipes, headers and tubes, steam turbine rotors and blades, and nuclear pressure vessels. These components typically experience long service exposure, high temperature under high loading conditions, corrosive media and neutron irradiation. The focus of this paper will be on the irradiation effects
Revision of the APGEMS Dose Conversion Factor File Using Revised Factors from Federal Guidance Report 12 and 13.
The Air Pollutant Graphical Environmental Monitoring System (APGEMS) is used by the Hanford Emergency Operation Center (EOC) to provide refined plume modeling of releases involving radionuclides. The dose conversion factors (DCFs) used by APGEMS to convert air concentration to dose are stored in a file called HUDUFACT.dat; the DCFs are based primarily on ICRP 30 compiled in the late 1980âs. This report updates the DCFs using more recent values reported in the Environmental Protection Agencies (EPAs) Federal Guidance Report (FGR) 12 and 13. FGR 12 provides external exposure (air submersion) DCFs for radionuclides in air; FGR 13 provides DCFs for radionuclides from inhalation. DCFs were updated for only those radionuclides listed in the original HUDUFACT.dat file. Since FGR 13 provides inhalation dose conversion factors as a function of age, revised DCF files were created for APGEMS for each age group. The âadultâ DCF file is the most relevant to compare to the original DCF file being used in APGEMS; these DCF values are compared in this report
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PRex: an experiment to investigate detection of near-field particulate deposition from a simulated underground nuclear weapons test vent
A radioactive particulate release experiment to produce a near-field ground deposition representative of small-scale venting from an underground nuclear test was conducted to gather data in support of treaty capability development activities. For this experiment, aCOââdriven âair cannonâ was used to inject ÂčâŽâ°La, a radioisotope of lanthanum with 1.7âd half-life and strong gamma-ray emissions, into the lowest levels of the atmosphere at ambient temperatures.Witness plates and air samplers were laid out in an irregular grid covering the area where the plume was anticipated to deposit based on climatological wind records. This experiment was performed at the Nevada National Security Site, where existing infrastructure, radiological procedures, and support personnel facilitated planning and execution of the work. A vehicle-mounted NaI(Tl) spectrometer and a polyvinyl toluene-based backpack instrument were used to survey the deposited plume. Hand-held instruments, including NaI(Tl) and lanthanum bromide scintillators and high purity germanium spectrometers, were used to take in situ measurements. Additionally, three soil sampling techniques were investigated and compared. The relative sensitivity and utility of sampling and survey methods are discussed in the context of on-site inspection.Keywords: environmental transport, airborne, radioactivity, atomic bomb, accidents, transpor
Clinician and Parent Perspectives on Parent and Family Contextual Factors that Impact Community Mental Health Services for Children with Behavior Problems
The present study employed qualitative methods to examine multiple stakeholder perspectives regarding the role of parent and family contextual factors on community child mental health treatment for children with behavior problems. Findings suggest agreement between clinicians and parents on the number, types and importance of parent and family factors in childrenâs mental health services; however, stakeholders differed in reports of which factors were most salient. Specifically, clinicians endorsed most factors as being equally salient, while parents described a few salient factors, with parental stress and inadequate social support being the most frequently discussed. These qualitative data further elucidate the context of community services and have implications for evidence-based practice implementation and improving community care
Comparison of Selected Physical and Mechanical Properties of Red Maple (Acer Rubrum L.) and Aspen (Populus Grandidentata Michx.) Flakeboard
Wood from red maple (Acer rubrum L.) and aspen (Populus grandidentata Michx.) was processed and fabricated into flakeboards with a target density of 50 lb/ft3. The data collected served as a basis for evaluating red maple as a potential raw material for flakeboard. Within the study parameters, random and aligned flake orientations were compared for both species. Moisture content, density, and flake alignment measurements revealed within- and between-board uniformity. Red maple flake-boards equaled or exceeded the performance of aspen flakeboards in static bending, internal bond, and nail withdrawal tests. In addition, red maple flakeboards containing randomly oriented flakes required higher loads to failure in nail withdrawal and internal bond tests compared to mechanically aligned flakes. Dimensional stability data of the flakeboards were obtained by measuring thickness swell, water absorption, and linear expansion. For both the random and aligned boards, the measured values indicated no substantial difference between the aspen and red maple specimens. In addition, mechanical alignment of the flakes improved some of the properties of the flakeboards compared to the randomly oriented flakeboards
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