As microelectronic parts trend smaller so do their solder joints. The surface finish on a copper pad is expected to become a significant part of the total solder joint volume and therefore affect mechanical properties of the smaller solder joints. Two sample geometries and four different surface finishes for tin-silver-copper...
The purpose of this study was to address the implementation fidelity of one part of a professional development model developed by the Northwest Regional Educational Laboratory (NWREL). Specifically, this research investigates middle school teachers’ use of a formative feedback guide developed by NWREL staff, examining the reliability with which teachers...
The lentil strain of pea seedborne mosaic virus, PSbMV-L, was
distinguished from the standard isolates of PSbMV by a natural inoculum
reservoir in lentil seed and by separate resistance genes in Pisum
and Lens. PSbMV-L was intermediate in symptom severity between the
standard and New Zealand isolates of PSbMV.
Seed...
An experiment was conducted to evaluate the influence of forest fuels reduction on diet quality, botanical composition, relative preference, and foraging efficiency of beef cattle grazing at different stocking rates. A split plot factorial design was used, with whole plots (3 ha) being fuel reduced or no treatment (control), and...
Hybrids with abnormal development were obtained when particular
genotypes of Phaseolus vulgaris L. were crossed. The phenotypic
aberrations of the F₁s included retarded growth, chlorosis of the
trifoliate leaves and the formation of adventitious roots on the
hypocotyls. The expression of the abnormalities was dependent on the
temperature. At high...
The purpose of this article is to explore student reasoning with regard to problems in logic, particularly those related to the Principle of Mathematical Induction (PMI). The five case studies presented build off of work done by other researchers, most notably Dubinsky and Harel, who both looked at how students'...
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Thomas P. Dick
The purpose of this article is to explore student reasoning with regard to
Responses of biological indicators of soil quality to winter cover cropping were measured on soil samples collected from 6 commercial growers' fields and two experiment research stations in the Willamette Valley of Oregon. The research stations were the North Willamette Research and Extension Center (Aurora, OR), and the Oregon State...
The purpose of this study was to investigate teaching models that may aid in
improving student's understanding of how to interpret graphs of kinematic variables.
The teaching models that were considered incorporated the use of cooperative groups
and calculator-based laboratory instruments, alone and in concert. The subjects used in
this...
Humboldt County has several areas which have naturally
high to extreme wildland fire hazards. Recent settlement within
these areas increases the likelihood of a destructive fire. This
report examines the extent and degree to which climate, slope and
vegetation influence the wildland fire hazard in Humboldt County,
as well as...
An extensive literature survey investigated methods and approaches
for evaluating intangible economic factors at the strategic
and tactical levels of managerial decision making. These sources
provided: 1) the background for a theoretical decision making
algorithm developed for comparing alternative economic proposals
for effectiveness at the strategy levels, and 2) a...
The response of sweet corn (Zea mays L. var. rugosa cultivar
Jubilee) to 12 populations and four nitrogen rates was studied in a
field experiment. Populations ranged from 43, 904 to 329,800
plants/ha with nitrogen levels ranging from 0 to 224 Kg/ha. A systematic
spacing design was used. Plant height,...
The rapid decline of marine ecosystems worldwide and the failure of traditional single species management pushed for the development of ecosystem-based conservation measures such as marine protected areas (MPA) to slow the loss of marine biodiversity. One approach to MPA creation advocates targeting marine megafauna (e.g., marine mammals, seabirds, sharks,...
Contamination of recreational and shellfish waters with fecal pollution is a major water quality issue with associated economic impacts and human health risks. Reliable fecal source identification and rapid, quantitative analyses are essential components of risk assessment. Enteric bacteria that are endemic to specific hosts have a potential role as...
Zinc Sulfide (ZnS) thin film, with a wide band gap, has been used for many applications, such as buffer layer for CIGS solar cells, light emitting diodes and thin film electroluminescent devices.
In this work, ZnS thin films were prepared using two different deposition processes. In the first method, ZnS...
Two summertime days were investigated, 27 and 28 June 1973,
to observe the changes in the environment that led to the severe hailstorm
on 28 June in the National Hail Research Experiment (NHRE)
network, Colorado. Within the network thermodynamic analyses
revealed the 28th to have:
(1) Above-average low-level moisture.
(2)...
Common root rot is a major disease of commercially grown snap bean (Phaseolus vulgaris L.) on the irrigated sandy soils of central Wisconsin. The objective of this study was to determine the relationships between soil properties and suppressiveness to common root rot of snap bean (causal agent Aphanomyces euteiches) in...
Forest harvest can have significant impacts on forest ecosystems that may influence the capacity of soils to sequester carbon (C). The microbial community controls decomposition, which is a critical process in partitioning litter- and root-C between CO₂ and storage in semi-permanent soil-C pools. The objectives of this study were to...