Green Tech Labs (United States)

Given the environmental impact of polymers on our daily lives, the development of biodegradable polymers is becoming increasingly critical. Poly(diisobutyl glycolide)-polyglycolide (PDIBG-PGA) and poly(diisopropyl glycolide)-polyglycolide (PDIPG-PGA) copolymers, which are structurally similar to polylactic-co-glycolic acid (PLGA) polyesters frequently used in the field of biomaterials, were synthesized via ring-opening polymerization (ROP) of glycolide with l-diisobutyl glycolide (l-DIBG) or l-diisopropyl glycolide (l-DIPG), respectively, in various molecular weights (M w GPC: 15.5-40.0 kDa) and in high yields (up to 85.0%). The wettability characteristics of biodegradable polymers are important not only in air but also for their behavior in underwater environments. PDIBG-PGA silica composites, due to their amphiphilic nature, exhibited water contact angles between 72° and 85° in air, unaffected by the increasing addition of hydrophilic silica nanoparticles. However, underwater-oil contact angles increased from 75° to 165° as a result of the higher silica nanoparticle content and enhanced surface roughness. When the silica content reached 30%, the surface demonstrated self-cleaning and oil-repellent properties underwater, attributed to the Cassie state, which trapped air within the surface's hierarchical roughness. Furthermore, the surface free energy (SFE) values of PDIBG-PGA and PDIPG-PGA copolymer films were evaluated using the Owens-Wendt method, which revealed an increasing underwater hexadecane contact angle as the polar component interactions increased. Differential scanning calorimetry analysis revealed that all synthesized copolymers were amorphous, and the glass transition temperatures (T g) increased with the increase in the molecular weight of the copolymers (for instance, M n GPC: 9560 g/mol → T g: 25.1 °C vs M n GPC: 20,850 g/mol → T g: 32.3 °C for PDIBG-PGA; M n GPC: 10,670 g/mol → T g: 37.7 °C vs M n GPC: 23,360 g/mol → T g: 42.3 °C for PDIPG-PGA). The molecular weight decreases of 88.3% and 76.5% and mass losses of 36.7% and 12.3% were observed for PDIBG-PGA and PDIPG-PGA copolymers after 8 weeks of hydrolytic degradation, respectively. The faster degradation of PDIBG-PGA (T g: 25.1 °C) than PDIPG-PGA (T g: 37.7 °C) may be attributed to the T g below the hydrolytic degradation temperature (37 °C) because of an increase in the mobility of PDIBG-PGA polymer chains, allowing water molecules to transfer more easily through the matrix.

Energy losses due to snow coverage can be high in climates with large annual snowfall. These losses may be reduced with region-specific system design guidelines. One possible factor in snow retention on PV systems could be frame presence and/or shape. Sandia is studying the effect of module frame presence on photovoltaic module snow shedding for a pair of otherwise-identical PV systems in Vermont. The results of this study provide a summary of the findings after the 2018-2019 winter period. The results clearly show that the presence of a frame inhibits PV performance in mild winter conditions.

This chapter describes how the iLab academic program at Winooski High School integrates genre-based pedagogy in a project-based learning environment for students to investigate STEAM topics. The iLab is a high school course that allows students to explore their interests in STEAM related projects, work with community experts, and share their learning. While topics focus on STEAM related projects, the work involves literacy instruction in all four domains: speaking, listening, reading, and writing. Using a genre-based pedagogy approach, we examine student work of new Americans, who are English learners, to understand how authentic learning opportunities in a project-based learning environment allow students to become conversant in the language of STEAM while learning the professional skills needed to become career and college ready.

The two studies reported on in this paper examine the features of words that distinguish students’ performances on vocabulary assessments as a means of understanding what contributes to the ease or difficulty of vocabulary knowledge. The two studies differ in the type of assessment, the types of words that were studied, and the grade levels and population considered. In the first study, an assessment of words that can be expected to appear with at least moderate frequency at particular levels of text was administered to students in grades 2 through 12. The second study considered the responses of fourth- and fifth-grade students, including English learners, to words that teachers had identified as challenging for those grade levels. The effects of the same set of word features on students’ vocabulary knowledge were examined in both studies: predicted appearances of a word and its immediate morphological family members, number of letters and syllables, dispersion across content areas, polysemy, part of speech, age of acquisition, and concreteness. The data consisted of the proportion of students who answered an item correctly. In the first study, frequency of a word’s appearance in written English and age of acquisition predicted students’ performances. In the second study, age of acquisition was again critical but so too were word length, number of syllables, and concreteness. Word location (which was confounded by word frequency) also proved to be a predictor of performance. Findings are discussed in relation to how they can inform curriculum, instruction, and research.

GC/IRMS was used to measure the carbon isotopic signature (δ13CV-PDB) of the Brazilian sugarcane bioethanol.

Fairbairn's secular object relations model of the development of the human personality emphasizes the power of the environment to form inner ego structures and the ensuing tragic results for all human infants who are faced with an unnurturing environment. Every act that children take to insure their continuing attachment to a frustrating, yet tantalizing object undermines their developing ego structure. The consequence of severely compromised ego structures is repetition compulsion in adulthood, as illustrated by the battered-woman syndrome. Each of the engorged and unrealistic part-ego structures seeks out external objects to re-enact the original relationship that created them. The consequence of a severely rejecting childhood can be endless abuse or death.

Alzheimer’s disease (AD) is an age-related disorder characterized by progressive neurological impairment. Among neurotransmitters affected, the loss of forebrain cholinergic neurons has been well documented with the results contributing to the idea that therapies based on cholinergic pharmacology would be useful treatments in AD (Bartus et al., 1982). Among those suggested have been acetylcholinesterase (AChE) inhibitors and muscarinic agonists. Clinical studies have shown that the AC inhibitor tacrine is therapeutically active (Knapp et al., 1994). However, robust and reproducible clinical data with classical muscarinic agonists have been variable and no agonists have been approved to date for AD treatment.KeywordsMorris Water MazeMuscarinic AgonistMuscarinic Receptor SubtypeProgressive Neurological ImpairmentMuscarinic Receptor AgonistThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

For many years the wire industry has worked to upgrade the high temperature performance of low-cost insulating materials. One technique that has been developed is cross-linking by irradiation. Introduced 21 years ago, the irradiation process is a simple one. After the thermoplastic compound is extruded onto wire, it is exposed to high energy electrons from an electron accelerator. The energy from the fast moving electrons is intense enough to change the chemical structure of many materials. In a properly formulated polymer system this change can cause extensive cross-linking and even change a thermoplastic to an insoluble, infusible thermosetting plastic.

Journal Article Relocation of the elderly Get access Beverly A. Yawney, MSW, Beverly A. Yawney, MSW Director of Social Services Fanny Allen Hospital, Winooski, Vermont. Search for other works by this author on: Oxford Academic PubMed Google Scholar Darrell L. Slover, Ph.D. Darrell L. Slover, Ph.D. Assistant Professor School of Social Work and All-University Gerontology Center, Syracuse University, Syracuse, New York. Search for other works by this author on: Oxford Academic PubMed Google Scholar Social Work, Volume 18, Issue 3, May 1973, Pages 86–95, https://doi.org/10.1093/sw/18.3.86 Published: 01 May 1973