TB125: Fertilization of Eastern White Pine (Pinus strobus L.) in Maine Shows Economic Potential

Plots in seven eastern white pine sawlog stands were treated with nitrogen at rates of 0, 56, 112, and 224 kg/ha. After four years the largest increase in basal area growth, 0.31 dm2 /tree, and volume growth, 13.0 m3 /ha, occurred in plots that received 112 kg/ha. It appears that an application rate of 112 kg/ha may provide a real return of 15% or more in some stands.https://digitalcommons.library.umaine.edu/aes_techbulletin/1061/thumbnail.jp

Detection of Rotational Spectral Variation on the M-type asteroid (16) Psyche

The asteroid (16) Psyche is of scientific interest because it contains ~ 1% of the total mass of the asteroid belt and is thought to be the remnant metallic core of a protoplanet. Radar observations have indicated the significant presence of metal on the surface with a small percentage of silicates. Prior ground-based observations showed rotational variations in the near-infrared (NIR) spectra and radar albedo of this asteroid. However, no comprehensive study that combines multi-wavelength data has been conducted so far. Here we present rotationally resolved NIR spectra (0.7-2.5 microns) of (16) Psyche obtained with the NASA Infrared Telescope Facility. These data have been combined with shape models of the asteroid for each rotation phase. Spectral band parameters extracted from the NIR spectra show that the pyroxene band center varies from ~ 0.92 to 0.94 microns. Band center values were used to calculate the pyroxene chemistry of the asteroid, whose average value was found to be Fs30En65Wo5. Variations in the band depth were also observed, with values ranging from 1.0 to 1.5%. Using a new laboratory spectral calibration we estimated an average orthopyroxene content of 6+/-1%. The mass-deficit region of Psyche, which exhibits the highest radar albedo, also shows the highest value for spectral slope and the minimum band depth. The spectral characteristics of Psyche suggest that its parent body did not have the typical structure expected for a differentiated body or that the sequence of events that led to its current state was more complex than previously thought.Comment: 21 pages, 8 figures, 2 tables, published in The Astronomical Journa

BYOE: Making Connections between Fluid Mechanics and Abstract Painting

This bring your own experiment (BYOE) paper details two iterations of a hands-on painting project that has been well-received by fluid mechanics students. In the conception of this project the authors have explored many of the relevant parameters for different painting techniques: drip painting, pendulum painting spray painting, and acrylic pours – one subset of which is spinning pours. These methods were explored both in terms of relevant fluid mechanic phenomenon as well as with hands-on experimentation, reviewing instructional videos and talking with artists. These efforts led to creation of short instructional videos that students can watch before undertaking their own attempts at creating a work of art. To date this project has been conducted as an extra credit opportunity, though discussion is presented on how the general idea could be deployed as a more traditional experimental lab or as a fun, yet relevant, end of semester lab activity. While the act of creating the fluid art inherently involves learning outcomes related to the importance of thinking creatively, exploring curiosity, prototyping and creating a product with limited project constraints, the instructor can determine the rigor of learning outcomes related to fluid mechanic principles with an accompanying written assignment. This BYOE paper is written with the goal of making the implementation of this project, or some variation of it, straightforward for instructors. Keeping material costs low was part of this consideration and set-up descriptions are provided as well as parts lists

Modeling Soil Water Contents and Their Effects on Stream Flow in Kentucky

Soil water contents of eight important soil series in Kentucky were measured periodically during the summer growing season for four years, 1977 through 1980. The soils divided into three groups according to their behavior. The first group (Maury and Crider) is well-drained and never showed excess water above field capacity at any time during the four seasons. The second group (Zanesville, Lowell, Calloway, Grenada and Shelbyville) showed perched water tables at times, especially during the early part of the growing season. The third group was represented by the Huntington soil which has a permanent water table. The in-situ field capacity or upper limits was determined on numerous samples of the Maury, Crider and Shelbyville soil series. Variation within series was rather low, indicating that samples taken at one site are representative of the soil in general. A model for estimating the soil water in each 15 cm layer was developed and proved to work very well with both Maury and Crider soils. Lowell soil was predicted poorly by the model, with other soils being intermediate. A variation of the model which assumed that the lowest layer of the Huntington was always at the upper limit due to a permanent water table also worked well. The water calculated from the model as deep drainage was used as a measure of increase in streamflow and compared to measured streamflow on three watersheds and four soils in 1978 and 1979. The R2 values ranged from 0.41 to 0.95 and the slope, which ideally should be 1.0, ranged from 0.54 to 1.36. The quantitative measure of streamflow was not satisfactory but the prediction of events was quite good. Modifications in the model that seem to be required include provisions for evaporation from foliage with small rains, higher evapotranspiration at lower soil water contents, less deep drainage with small rains and an aquifer storage factor

Micro-bubble dynamics in two-phase flow through a micro-channel

An experimental investigation into the behavior of micro-bubbles flowing through a micro-channel has been conducted. Experiments were performed within a rectangular micro-channel with dimensions of 5 cm x 13.2 mm x l30 jim. Bubbles were generated in an electrolyte solution by electrolysis at the lower channel wall near the inlet. A non-intrusive optical set-up utilizing laser induced fluoresce (LIF) from Rhodamine 6G and particle image velocimetry (PIV) seed particles was developed to obtain information on both phases of the flow using a single camera. The gas phase measurements are discussed here, while fluid phase data is discussed in a concurrent study. Measurements of bubble size, distribution, and area fraction were taken at four different heights above the lower channel wall for three different flow rates (40 mL/min, 80 mL/min, and 100 mL/min) and two different electrolysis voltages used to generate the bubbles. Digital images were processed with an involved, active algorithm intended to reduce noise. Bubble velocity measurements were obtained through a bubble pairing algorithni. It is determined that the use of electrolysis for bubble generation provides poor control of global area fractions while producing a non-homogenous bubble distribution across the channel width. Experimental results reveal that much noise remains after the digital image processing. Despite this, it is found that for measurements taken at the same channel position and local area fraction an increase in flow rate leads to an increase in mean separation distance of the bubbles. There is also evidence to suggest that under these conditions an increased flow rate causes small bubbles to disperse more quickly into the channel than large bubbles. The bubble velocity results are shown to be very questionable by comparison with theoretical flow rates through the channel. Finally, a sensitivity analysis is done on the digital image processing technique used which reveals possible improvements that can be made to improve noise reducing capabilities