28130 research outputs found
Sort by
Indian Pond Project Dam 1952-55
No full textSection of dam have concret on the right side of the frame, and the upper part is incomplete.https://digitalcommons.usm.maine.edu/hamilton-thayer-photographs/1223/thumbnail.jp
Chesuncook Village
No full textA shoreline view of Chesuncook village, reflected on the waterhttps://digitalcommons.usm.maine.edu/hamilton-thayer-photographs/1231/thumbnail.jp
Bateau 2
No full textFour men on a bateau, leaving the dock. Tree line is on the base of a mountain scape in the background. A docked bateau is barely visible in the foreground on the left side.https://digitalcommons.usm.maine.edu/hamilton-thayer-photographs/1284/thumbnail.jp
Docked Ferry Boat
No full textBoat placed on top of a neatly stacked logs.https://digitalcommons.usm.maine.edu/hamilton-thayer-photographs/1301/thumbnail.jp
D.T. Sanders house & Store 1897
No full textPhotograph of Sanders house and store. Handwritten on verso: 1897 D.T. Sanders House and Store.https://digitalcommons.usm.maine.edu/hamilton-thayer-photographs/1316/thumbnail.jp
2nd Dam at East Outlet n.d.
No full textA faded photograph of a dam under construction. A canoe is flipped on the wooden dam where a couple of men are lounging. Two men are standing on and next to a canoe on the water on the left side of the photograph.https://digitalcommons.usm.maine.edu/hamilton-thayer-photographs/1319/thumbnail.jp
[…] Sq*** Brook
No full textPhotograph of a homestead, and a bee keeping farm in the front yard. A mountain can be spotted in the background, and a log bridge at the far right of the frame, leading to a dirt path.https://digitalcommons.usm.maine.edu/hamilton-thayer-photographs/1103/thumbnail.jp
The Free Press Vol. 57, Issue 2, 09-08-2025
No full textESPORTS Arena Opening--Will Susan Collins Lose?--MovieTalk and Events--World Cup in America--Letters from the Editorshttps://digitalcommons.usm.maine.edu/free_press/1344/thumbnail.jp
Olefin Metathesis in Water: Speciation of a Leading Water-Soluble Catalyst Pinpoints Challenges and Opportunities for Chemical Biology
No full textThe metathetical modification of biomolecules in aqueous environments holds great promise for advances at the interface of chemistry, biology, and medicine. However, rapid degradation of the metathesis catalysts necessitates their use in large stoichiometric excess, resulting in undesired side-reactions promoted by the ruthenium products. Although water is now known to play a central role in catalyst decomposition, the elusive nature of the intermediates has hampered insight into the pathways involved. We describe the detailed speciation in water of AquaMet (AM), the dominant ruthenium catalyst used for aqueous metathesis, and implications for catalysis. Potentiometric and spectroscopic speciation studies reveal that only trace AM is present under the pH-neutral, salt-free conditions routinely employed in synthetic applications of aqueous metathesis. Instead, metathesis-inactive hydroxide species dominate. Even at pH 3, Ru–H2O complexes dominate in 0.01 M NaCl(aq), and the water ligands are readily deprotonated as the pH is increased. Raising NaCl(aq) concentrations to 1 M suppresses deprotonation events below pH 8, stabilizing AM as the dominant solution species at neutral pH, and significantly expanding the metathesis-compatible regime. Hitherto unrecognized catalyst solubility issues are also revealed, pointing toward avenues for advance. More broadly, the capacity to directly link catalyst environment to structure and performance opens new opportunities for olefin metathesis in complex, water-rich settings
