918 Matching Results

Search Results

"Stand With Wendy" Twitter Dataset

Description: This dataset contains Twitter JSON data for several Twitter search queries collected the week following the filibuster by Wendy Davis in the Texas Senate related to Senate Bill 5, using the twarc (https://github.com/edsu/twarc) package that makes use of Twitter's search API. A total of 560,954 Tweets make up the combined dataset.
Date: 2013-06-25/2013-07-03
Creator: Phillips, Mark Edward
Partner: UNT Libraries

A Joint Theory and Experimental Project in the Synthesis and Testing of Porous COFs for On-Board Vehicular Hydrogen Storage

Description: Conventional storage of large amounts of hydrogen in its molecular form is difficult and expensive because it requires employing either extremely high pressure gas or very low temperature liquid. Because of the importance of hydrogen as a fuel, the DOE has set system targets for hydrogen storage of gravimetric (5.5 wt%) and volumetric (40 g/L) densities to be achieved by 2015. From our continuous efforts on hydrogen storage, it is believed that metalation of highly porous solids with high-valence metals is promising and provides a rational direction to realize high volumetric hydrogen density near room temperature. This grant was focused on the study of high surface area covalent organic frameworks (COFs) with these specific objectives (1) to introduce potential metal binding sites through the COF synthesis and (2) to implement metalation experiments and evaluate their respective hydrogen adsorption properties. To maximize our efforts, simulation calculations were also performed (prior to experiments) for the prediction of binding enthalpy of hydrogen for molecular building units containing transition metals and promising COF structures to increase volumetric hydrogen uptake at room temperature. In this effort, first molecular building units with optimal binding energy for hydrogen storage (20 kJ/mol) were designed by quantum mechanical (QM) methods. Employing these results, it was revealed that one of metalated COFs takes up 60 g/L (total) of H2 at 100 bar and 298 K. To realize proposed COF structures, chemistry of COF synthesis has been developed; for instance, new air stable COFs were synthesized via hydrazone (COF-41 to 43) and imine condensation (COF-301, 320, 340, and 366) and some of them were tested the effect on metalation. Finally, a new triazine COF with high volumetric hydrogen uptake capacity was presented as a proposed future direction.
Date: June 29, 2013
Creator: Yaghi, Omar M. & Goddard, William A.
Partner: UNT Libraries Government Documents Department

Final Technical Report-the Ecology and Genomics of co2 Fixatiion in Oceanic River Plumes

Description: Oceanic river plumes represent some of the most productive environments on Earth. As major conduits for freshwater and nutrients into the coastal ocean, their impact on water column ecosystems extend for up to a thousand km into oligotrophic oceans. Upon entry into the oceans rivers are tremendous sources of CO2 and dissolved inorganic carbon (DIC). Yet owing to increased light transmissivity from sediment deposition coupled with the influx of nutrients, dramatic CO2 drawdown occurs, and plumes rapidly become sinks for CO2. Using state-of-the-art gene expression technology, we have examined the molecular biodiversity of CO2 fixation in the Mississippi River Plume (MRP; two research cruises) and the Orinoco River Plume (ORP; one cruise). When the MRP extends far into the Gulf because of entrainment with the Loop Current, MRP production (carbon fixation) can account for up to 41% of the surface production in the Gulf of Mexico. Nearer-shore plume stations (“high plume,” salinity< 32 ppt) had tremendous CO2 drawdown that was correlated to heterokont (principally diatom) carbon fixation gene expression. The principal form of nitrogen for this production based upon 15N studies was urea, believed to be from anthropogenic origin (fertilizer) from the MRP watershed. Intermediate plume environments (salinity 34 ppt) were characterized by high levels of Synechococcuus carbon fixation that was fueled by regenerated ammonium. Non-plume stations were characterized by high light Prochlorococcus carbon fixation gene expression that was positively correlated with dissolved CO2 concentrations. Although data from the ORP cruise is still being analyzed, some similarities and striking differences were found between the ORP and MRP. High levels of heterokont carbon fixation gene expression that correlated with CO2 drawdown were observed in the high plume, yet the magnitude of this phenomenon was far below that of the MRP, most likely due to the lower levels of anthropogenic nutrient input. ...
Date: June 21, 2013
Creator: Paul, John H.
Partner: UNT Libraries Government Documents Department

Nanoimprinted plasmonic nanocavity arrays

Description: This article demonstrates high resonant absorption of visible light with a plasmonic nanocavity chain structure fabricated through resistless nanoimprinting in metal (RNIM).
Date: June 17, 2013
Creator: Kim, Sangsik; Xuan, Yi; Drachev, Vladimir P.; Varghese, Leo T.; Fan, Li; Qi, Minghao et al.
Partner: UNT College of Arts and Sciences

The President's Climate Action Plan

Description: A report about minimizing climate change in the United States. It focuses on carbon pollution, preparing for the impacts of climate change, and leading international efforts to fight global climate change and prepare for its impacts.
Date: June 2013
Creator: United States. The White House.
Partner: UNT Libraries Government Documents Department

A Lawless Breed: John Wesley Hardin, Texas Reconstruction, and Violence in the Wild West

Description: John Wesley Hardin! His name spread terror in much of Texas in the years following the Civil War as the most wanted fugitive with a $4000 reward on his head. A Texas Ranger wrote that he killed men just to see them kick. Hardin began his killing career in the late 1860s and remained a wanted man until his capture in 1877 by Texas Rangers and Florida law officials. He certainly killed twenty men; some credited him with killing forty or more. After sixteen years in Huntsville prison he was pardoned by Governor Hogg. For a short while he avoided trouble and roamed westward, eventually establishing a home of sorts in wild and woolly El Paso as an attorney. He became embroiled in the dark side of that city and eventually lost his final gunfight to an El Paso constable, John Selman. Hardin was forty-two years old. Besides his reputation as the deadliest man with a six-gun, he left an autobiography in which he detailed many of the troubles of his life. In A Lawless Breed, Chuck Parsons and Norman Wayne Brown have meticulously examined his claims against available records to determine how much of his life story is true, and how much was only a half truth, or a complete lie. As a killer of up to forty men, Hardin obviously had psychological issues, which the authors probe and explain in laymen’s terms. To Hardin, those three dozen or more killings were a result of being forced to defend his life, his honor, or to preserve his freedom against those who would rob or destroy him or his loved ones. Was he a combination freedom fighter/man-killer, or merely a blood-lust killer who became a national celebrity? This deeply researched biography of Hardin and his friends and family will remain ...
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: June 15, 2013
Creator: Parsons, Chuck & Brown, Norman Wayne
Partner: UNT Press