Invasion of transition hardwood forests by exotic Rhamnus frangula: Chronology and site requirements

The invasion chronology and site requirements of the exotic, invasive shrub, glossy buckthorn (Rhamnus frangula), were studied within intact transition hardwood---hemlock---white pine forests in Durham, NH. Data were collected from 63 plots (7 sites with 9 plots each). Within sites, plots were arranged over a topographic gradient with 3 plots in each of 3 topographic positions (upper, middle, and lower slope). From each plot, information on soil nutrients and texture, soil moisture, overstory community composition, and canopy openness was collected. Densities of R. frangula in two size classes (≥1 m in height, \u3c1 m in height) within each plot were calculated. Morphological data (height, diameter at stem base, number of live and dead stems, and age) were collected from each individual ≥1 m tall. R. frangula invaded these intact, closed-canopy forests over 30 years ago and the invasion has continued, with population density increasing over time. Nominal logistic regression suggested that site, topographic position, and overstory community type played a role in whether or not R. frangula was present in a plot. Plots on upper slopes dominated by Tsuga canadensis were less likely to become invaded than other plots. Multiple linear regression showed that density of R. frangula (≥1 m) increased with time since invasion and increasing soil quality. Density of R. frangula (\u3c1 m) was positively influenced by time since invasion, canopy openness, and density of R. frangula (≥1 m). Multiple regressions also showed that mean age and age of oldest R. frangula per plot were higher in plots with higher soil moisture content. Size of R. frangula individuals (i.e. height, diameter) generally increased with mean age of stems. The results show that successional, transition hardwood forests can be invaded by R. frangula and should not be overlooked when managing against this species. Special attention should be given to low topographic positions and areas with rich soils, while upland areas with dense hemlock canopy are much less likely to experience heavy invasion by R. frangula.

Use of DSC and DMA Techniques to Help Investigate a Material Anomaly for PTFE Used in Processing a Piston Cup for the Urine Processor Assembly (UPA) on International Space Station (ISS)

Human urine and flush water are eventually converted into drinking water with the Urine Processor Assembly (UPA) aboard the International Space Station (ISS). This conversion is made possible through the Distillation Assembly (DA) of the UPA. One component of the DA is a molded circular piston cup made of virgin polytetrafluoroethylene (PTFE). The piston cup is assembled to a titanium component using eight fasteners and washers. Molded PTFE produced for spare piston cups in the first quarter of 2010 was different in appearance and texture, and softer than material molded for previous cups. For the suspect newer PTFE material, cup fasteners were tightened to only one-half the required torque value, yet the washers embedded almost halfway into the material. The molded PTFE used in the DA piston cup should be Type II, based on AMS 3667D and ASTM D4894 specifications. The properties of molded PTFE are considerably different between Type I and II materials. Engineers working with the DA thought that if Type I PTFE was molded by mistake instead of Type II material, that could have resulted in the anomalous material properties. Typically, the vendor molds flat sheet PTFE from the same material lot used to mold the piston cups, and tensile testing as part of quality control should verify that the PTFE is Type II material. However, for this discrepant lot of material, such tensile data was not available. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were two of the testing techniques used at the NASA/Marshall Space Flight Center (MSFC) to investigate the anomaly for the PTFE material. Other techniques used on PTFE specimens were: Shore D hardness testing, tensile testing on dog bone specimens and a qualitative estimation of porosity by optical and scanning electron microscopy

The ozone oxidation of ethylene as it pertains to air pollution

Reaction kinetics of ozone oxidation of ethylene pertinent to air pollutio

MSSS Curriculum Connection Series - Lesson Number: 06

Political events can impact citizens across borders and through time. Folklore is powerful because it provides a vehicle for cross-cultural connections

Contributing Factors that Influence a Student’s Decision Regarding a Juvenile Sentence

On March 21, 2000, 15-year-old Alonza Thomas ran away from home. During Alonza’s time away from home, he met a man and went to his apartment. Alonza stayed at his apartment for a couple of days (McNally, 2018). The man cooked for him and gave him a place to sleep. Alonza tried to go home, but the man became irrational and approached Alonza with a gun, stating “You think you’re gonna eat my food for free? Live in my house and just walk out? And think things come free like that? No, you’re gonna have to rob this store. ...You’re gonna do this for me” (McNally, 2018). Fearing for his life Alonza did as he was told; he went to the Fastrip gas station and placed a gun at the clerk\u27s chest. Alonza held his gun the way he saw actors hold their gun in movies such as “Menace II Society” and Boyz n the Hood.” He told the clerk to empty the register. The clerk hit his hand on the glass and the gun discharged. Alonza tried to make a run for it, but the store clerk leaped on top of Alonza and began beating him. The clerk and other workers held Alonza at gun point until the officers arrived. Alonza was charged with three counts of second-degree robbery, one count of assault with a firearm and enhancements for personal use of a firearm (McNally, 2018)

MSSS Curriculum Connection Series - Lesson Number: 12

Students are the historical actors of the future. Their actions, attitudes and artifacts are the stuff future historians will collect and analyze in order to understand our time. Although we may not consider our lives “historic” to historians of the future they may be. Likewise, the actions, attitudes and artifacts collected in the Maine Song and Story Sampler may not have been considered historic by their creators, but are worthy of our consideration today. In this exercise students will have the opportunity to analyze one artifact from the MS&SS website from the perspective of a professional archivist to determine its historical context and make recommendations regarding its future disposition

Assessing ASR Potential of Hardened Concrete and The Use of Rice Husk Ash to Mitigate ASR

This two part research study was created to first develop a new process using existing test methods to determine the Alkali-Silica Reaction (ASR) potential of hardened concrete that is exposed to external alkalis and secondly to determine the ASR mitigation potential of using rice husk ash (RHA) as a supplementary cementitious material (SCM). The first part of the research study was completed by using a new aggregate extraction procedure that uses a combination of hydrochloric acid treatments and abrasion to remove the cement paste from the aggregate. This extracted aggregate was then crushed down to the specified sizes and used in an ASTM C 1260 test. The calibration of the test was done by extracting three different types of aggregate from ASTM C 1293 samples from a previous study at Clemson University that had ASR problems and then using the extraction process to remove enough aggregate to conduct a post removal ASTM C 1260 test. The results of the post removal ASTM C 1260 test were then compared to the initial ASTM C 1260 tests that were run on the three control aggregates. The new process was successful in the sense that the aggregates were classified with the same reactivity for the pre and post removal ASTM C 1260 tests. This process was then used on cores from two airports, both of these airports are known to have ASR problems. The test was again successful in determining the reactivity of the aggregates as potentially having a deleterious behavior. As for the determination of the mitigation potential of RHA used as an SCM, this was done by first physically characterizing the material, determining the pozzolanic activity index, and then using the RHA in an ASTM C 1567 test to determine the mitigation potential. The results showed that the material has a low specific gravity with a high xi surface area and high silica content. The pozzolanic activity index was the highest at a replacement level between 10 and 15% by mass replacement. The results of the ASTM C 1567 tests showed that as the replacement level increases so does the expansions, which is a clear sign that the use of RHA failed as an ASR mitigator. The reason for this is unknown, but may be due to either the vesicular structure of the RHA grains creating direct routes or pathways for the external alkalis to be transported or the chemical makeup of the ash causing an interaction with the reactive silica and external alkal

The Digitization of Japanese Translations of the Rvf in the Oregon Petrarch Open Book

The article discusses the benefits of having translations of Petrarch available in Japanese, and describes a project to digitize portions of a Japanese translation of the Canzoniere. Conversion from printed Japanese to HTML posed several interesting challenges