A Comparison Study of Two Synthesis Methods for Polymer of Intrinsic Microporosity 1 (PIM-1)

Polymers of Intrinsic Microporosity (PIMs) are an emerging polymeric material class for molecular sieving applications. This study focuses on PIM-1, an alternating copolymer of 5,5’,6,6’-tetrahydroxy-3,3’,3,3’-tetramethyl-1,1’-spirobisindane and tetrafluoroterephthalonitrile synthesized via nucleophilic aromatic substitution. PIM-1 been widely studied as a gas separating material and filtering membrane, but in this case, it is studied as a battery separator material. PIM-1’s microporous (pore diameters less than 2 nm) structure allows smaller favorable ions to transport while preventing larger ions and compounds from transporting. Two synthesis methods, round bottom flask synthesis and ball mill synthesis, of PIM-1 are compared to see any improved characteristics. The primary goal of this study is to observe an increase in molecular weight, but other properties are evaluated as well. The calculated yield was higher for ball milled PIM-1 (51.5% round bottom flask vs. 62.8% ball mill). Size-exclusion chromatography (SEC), nuclear magnetic resonance (NMR) spectroscopy, and Brunauer- Emmett-Teller (BET) analysis were used to characterize each synthesized batch. Both PIM-1s had the same overall molecular weight (98,468 round bottom flask vs. 97,331 ball mill), but the ball milled PIM-1 had a lower polydispersity (2.372 round bottom flask vs. 1.728 ball mill). The ball-milled PIM-1 also revealed broader peaks and fewer impurities than RBF PIM-1 with NMR analysis. BET analysis revealed that both PIM-1s had similar expected porosities (658 m2/g vs. 642 m2/g). More research is needed to affirm that ball milling is a superior method

Iron Deficiency Anemia: An Unexpected Cause of an Acute Occipital Lobe Stroke in an Otherwise Healthy Young Woman

A 29-year-old caucasian woman who presented to the hospital with an acute onset of right eye visual disturbance and headache was found to have an acute left occipital lobe infarction. Past medical history was significant for iron deficiency anemia (IDA) secondary to menorrhagia. Her initial hemoglobin level was 7.8 G/DL, and her symptoms improved after iron and blood transfusions. Hypercoagulable studies were completed in the outpatient setting, and the results were unremarkable. Her acute stroke was most likely related to IDA as she had low cardiovascular risk factors along with a negative complete stroke workup

Habitat Preferences of the Eastern Hellbender in West Virginia

The Eastern Hellbender, Cryptobranchus alleganiensis alleganiensis, is a species of concern in West Virginia and is in need of management. An important component of conservation efforts will involve identifying suitable habitat for protection. The goal of this research was to locate populations and examine hellbender habitat preferences to help managers identify habitat for protection. Populations were located using rock turning surveys from May through November, 2006. Hellbenders may be sensitive to water chemistry, so the dissolved oxygen, pH, turbidity, specific conductivity, and water temperature were measured. Substrate composition may influence populations, so substrate was characterized with Wolman pebble counts. Crayfish relative abundance was measured because they are an important prey item. Mean habitat characteristics of sites where hellbenders were present and absent were compared with t-tests. Habitat variables were ordinated in princip al component analysis and examined in 2-dimensional ordination space to determine if sites where hellbenders were present grouped. Populations were found at 12% of sites, indicating that populations have declined in many streams. Hellbenders preferred sites with a large amount of gravel and cobble, cool water temperatures, low specific conductivity, and lower pH values. Gravel and cobble substrates may provide habitat for larval hellbenders and invertebrate prey items. Cool streams allow for more efficient cutaneous gas exchange. Low specific conductivity may indicate undisturbed conditions, suggesting hellbender populations were concentrated in less disturbed streams. Acidic conditions can alter prey communities and affect amphibian survival, so it was surprising to find populations in more acidic streams, although levels were above those known to harm stream ecosystems. Streams with similar habitat characteristics should be protected to conserve this unique salamander

Emission characteristics and dynamics of the stagnation layer in colliding laser produced plasmas

The expansion dynamics of ion and neutral species in laterally colliding laser produced aluminum plasmas have been investigated using time and space resolved optical emission spectroscopies and spectrally and angularly resolved fast imaging. The emission results highlight a difference in neutral atom and ion distributions in the stagnation layer where, at a time delay of 80 ns, the neutral atoms are localized in the vicinity of the target surface 1 mm from the target surface while singly and doubly charged ions lie predominantly at larger distances, 1.5 and 2 mm, respectively. The imaging results show that the ions were found to form a well defined, but compressed, stagnation layer at the collision front between the two seed plasmas at early times (Dt ~ 80 ns). On the other hand, the excited neutrals were observed to form a V-shaped emission feature at the outer regions of the collision front with enhanced neutral emission in the less dense, cooler regions of the stagnation layer

China Maritime Report No. 1: China’s Third Sea Force, The People’s Armed Forces Maritime Militia: Tethered to the PLA

Amid growing awareness that China’s Maritime Militia acts as a Third Sea Force which has been involved in international sea incidents, it is necessary for decision-makers who may face such contingencies to understand the Maritime Militia’s role in China’s armed forces. Chinese-language open sources reveal a tremendous amount about Maritime Militia activities, both in coordination with and independent of the People’s Liberation Army (PLA). Using well-documented evidence from the authors’ extensive open source research, this report seeks to clarify the Maritime Militia’s exact identity, organization, and connection to the PLA as a reserve force that plays a parallel and supporting role to the PLA. Despite being a separate component of China’s People’s Armed Forces (PAF), the militia are organized and commanded directly by the PLA’s local military commands. The militia’s status as a separate non-PLA force whose units act as “helpers of the PLA” (解放军的 助手) is further reflected in China’s practice of carrying out “joint military, law enforcement, and civilian [Navy-Maritime Law Enforcement-Maritime Militia] defense” (军警民联防). To more accurately capture the identity of the Maritime Militia, the authors propose referring to these irregular forces as the “People’s Armed Forces Maritime Militia” (PAFMM).https://digital-commons.usnwc.edu/cmsi-maritime-reports/1000/thumbnail.jp

Do Perceptions of Ballot Secrecy Influence Turnout? Results from a Field Experiment

Although the secret ballot has long been secured as a legal matter in the United States, formal secrecy protections are not equivalent to convincing citizens that they may vote privately and without fear of reprisal. We present survey evidence that those who have not previously voted are particularly likely to voice doubts about the secrecy of the voting process. We then report results from a field experiment where we provided registered voters with information about ballot secrecy protections prior to the 2010 general election. We find that these letters increased turnout for registered citizens without records of previous turnout, but did not appear to influence the behavior of citizens who had previously voted. These results suggest that although the secret ballot is a long-standing institution in the United States, providing basic information about ballot secrecy can affect the decision to participate to an important degree.

An Emerging Containment of (Legal) Concern: PFAS Legal Issues at the State and Federal Level

Per- and polyfluoroalkyl substances, or PFAS, are a class of man-made industrial chemicals that have been widely used in a variety of ways, primarily in water-resistant coatings and fire-fighting foam. Their widespread use has led to broad contamination threats to human drinking water sources, including surface and groundwater. As a result, they are an emerging contaminant of concern that are swiftly turning into a global health threat on the forefront of regulatory and policy debates. PFAS have been detected in both aquatic life and humans, and research is increasingly clear that there are concrete health risks to excessive exposure. Currently there are no binding federal restrictions of PFAS, leading some states to take the lead in developing regulations for this class of emerging contaminants. This paper will give a brief overview of what PFAS is, what the federal and state governments are doing about it, and various recommendations. This abstract has been taken from the authors\u27 introduction

RR Lyrae Variables in Two Fields in the Spheroid of M31

We present Hubble Space Telescope observations taken with the Advanced Camera for Surveys Wide Field Channel of two fields near M32—between 4 and 6 kpc from the center of M31. The data cover a time baseline sufficient for the identification and characterization of 681 RR Lyrae variables of which 555 are ab-type and 126 are c-type. The mean magnitude of these stars is = 25.29 ± 0.05, where the uncertainty combines both the random and systematic errors. The location of the stars in the Bailey diagram and the ratio of c-type RR Lyraes to all types are both closer to RR Lyraes in Oosterhoff type I globular clusters in the Milky Way as compared with Oosterhoff II clusters. The mean periods of the ab-type and c-type RR Lyraes are = 0.557 ± 0.003 and = 0.327 ± 0.003, respectively, where the uncertainties in each case represent the standard error of the mean. When the periods and amplitudes of the ab-type RR Lyraes in our sample are interpreted in terms of metallicity, we find the metallicity distribution function to be indistinguishable from a Gaussian with a peak at = –1.50 ± 0.02, where the quoted uncertainty is the standard error of the mean. Using a relation between RR Lyrae luminosity and metallicity along with a reddening of E(B – V) = 0.08 ± 0.03, we find a distance modulus of (m – M)_0 = 24.46 ± 0.11 for M31. We examine the radial metallicity gradient in the environs of M31 using published values for the bulge and halo of M31 as well as the abundances of its dwarf spheroidal companions and globular clusters. In this context, we conclude that the RR Lyraes in our two fields are more likely to be halo objects rather than associated with the bulge or disk of M31, in spite of the fact that they are located at 4-6 kpc in projected distance from the center