Nicholas E. Pingitore - US grants

The system Ag-S-Se is of considerable interest in materials research due to the optical, electrical, and thermo-electrical properties which typify these elements in the solid state. Three compounds are generally recognized as characterizing the system at room temperatures: Ag2S (monoclinic), Ag4SSe (orthorhombic), and Ag2Se (orghorhombic). Recently we have synthesized a series of intermediate compounds ranging in composition from the pure silver sulfide, through the silver sulfo- selenide, to the pure silver selenide. The compositional series appears to break into two solid solutions, one extending from Ag2S to approximately Ag4SO.65Se1.35 and the other encompassing Ag4SO.65Se1.35 to Ag2Se. In this project we hope to: 1.) Produce the phase diagram for the system Ag-S-Se and confirm the crystallography of the two solid solutions. 2.) Document the electrical, optical, and thermoelectric properties of these compounds. 3.) Investigate the fabrication of these materials as thin films. 4.) Determine possible commercial applications (e.g., dry cells, thermal sensors, electrochromic displays, non-linear optoelectronic devices) of these materials. This project represents the first look at the behaviors of new materials that are likely to possess interesting electrical, optical, and thermoelectric properties. Because the materials form solid solutions, their behaviors should be continuously variable with composition, with the potential for the creation of "designer properties" based on stoichiometry.

9450412 The proposed research encompasses the synthesis of pseudo-ternary compounds of the silver chalcogenides and the characterization and simulation of their physical and electrical properties. The ultimate aim is to relate structural information to the ionic conductivity and diffusivity of silver to obtain a deeper understanding of the mechanism of superionic conductivity which marks high temperature phases in the system Ag2S---Ag2Se--Ag2 Te. Data sets derived from x-ray diffraction,calorimetry, four-probe conductivity and x-ray absorption spectroscopy analyses will be incorporated into a computer model of the super ionic phases.

9814336
Pingitore

The mode of incorporation and consequent mobility of the trace and minor elements in coral skeletal aragonite are a concern to researchers who derive records of global and local change from chemical proxies in corals. We are using synchrotron-based x-ray absorption spectroscopy to determine the structural site location at the atomic level (e.g., substitution for calcium, occupation of defects, discrete phase) of such elements as Sr, U, Ba, Mg, and Pb in the skeletal carbonate of a variety of corals and other calcareous taxa.
Using transmission and analytic electron microscopy and electron probe microanalysis, we also will perform microstructural and microchemical characterization of the strontianite phase which we recently documented in coral aragonite. Knowledge of structural incorporation is fundamental to the development and validation of new data sets being derived from Mg, U, Pb, Cd, and Ba. The project results will be of interest to researchers studying sea surface temperatures, ocean circulation, marine pollution, biomineralization, and carbonate petrology. Because of the importance of carbonate minerals in surficial non-marine environments, our results also will have bearing on problems in radionuclide and toxic metal migration.

0116660
Pingitore

This grant, made through Major Research Instrumentation Program, provides partial support of the costs for upgrading the operating system of UTEP's 14-year-old, first generation Cameca SX-50 electron microprobe. We will acquire a control system upgrade to replace the antiquated DEC PDP-based software on our Cameca microprobe. The DEC system is no longer supported by DEC or Cameca; newly developed analytical and imaging capabilities have not been available to us. The original Kevex EDS (energy dispersive spectrometer) system likewise is seriously outdated and has no EDS imaging and mapping capability or light-element detection. We will replace this with a system featuring a full imaging and mapping package, high counting rate, and light-element detector window. UTEP's electron microprobe laboratory is a multi-user and multi-disciplinary facility. It serves research, research training and instructional functions for individuals and groups from across our campus, including members of the Colleges of Science, Engineering, Liberal Arts, and Health Sciences. The microprobe laboratory also assists individuals, businesses, educational institutions, government agencies, and non-governmental organizations in the El Paso-Juarez community and beyond. The three co-investigators and their research groups have 15 projects, currently underway, which will make use of the upgraded facility. These research projects include the following topics: tectonics, metamorphic reactions, phytoremediation, environmental bio-sensors, desert varnish, particulate matter air pollution, plutonism, biosorption of heavy metals, trace elements in corals, microprobe data quantification, speciation of metals in soil, and foram Mg/Ca paleothermometry. Additional microprobe equipment use on funded projects from other UTEP researchers includes such topic areas as pigments, catalytic materials, archaeology, health, soil salination, composites, and exotic alloys. Early and continued exposure to research is an essential part of UTEP's strategy to attract and retain students in science and engineering, particularly under-represented minorities. Mexican-Americans comprise approximately 2/3 of the student body at UTEP. Two of the Co-PIs are minority members, who serve as special role models and close student mentors. Instrumentation and hands-on laboratory experience are important to establish the "connection" with students that often determines their
academic choices, success, and ultimate career paths.
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This revised application for an Advanced Research Cooperation in Environmental Health (ARCH) grant links the University of Texas at El Paso (UTEP), a Minority Serving Institution (MSI), with the University of New Mexico Health Sciences Center (UNM HSC), a Research Intensive University (RIU). The central research hypothesis is that children breathing air in the most polluted parts of El Paso, TX, have an increased prevalence of asthma, which may be under detected in the area's medically underserved Hispanic children. The project builds on the research strengths and previous work of UTEP investigators in documenting significant air and soil pollution problems in El Paso, TX, and contiguous Juarez, Mexico, and on UTEP's recent successful programs in public health. The Core Research Project ties high-density (both spatial and temporal) air and soil quality data to the prevalence and intensity of asthma and respiratory distress in a cohort of 1200 households randomly selected from 100 stratified blocks in the El Paso community. The application has been completely revised with an improved environmental sampling design, development of a more expansive cohort, new environmental epidemiology expertise, and more productive interactions of all Pilot Projects with the Core Research Project. The Pilot Projects will monitor levels of pollutants, including PM2.5, carbon nanoparticles, toxic metals, polycyclic aromatic hydrocarbons (PAHs), atmospheric ozone, nitrogen dioxide (NO2), and volatile organic compounds (VOCs), and feed these data to the Research Core. In revised Project 1, lung function in children measured by Impulse Oscillometry (IOS) methods in a clinical setting will be compared to lung function measured with spirometry methods promotoras in the local communities. Project 2 is new and examines the relationship between indoor and outdoor air sample particle concentration and composition in a subset of the blocks in the Research Core Project. Project 3 is also new and will test for gases (NO2, ozone, and VOCs), again in neighborhoods tied to the Core. Revised Project 4 examines the hypothesis that the organic fraction of PM2.5 contributes to asthma via oxidized PAHs that activate cell signaling pathways important in inflammation and immediate type hypersensitivity leading to asthma exacerbations. Project 5 performs innovative studies on carbon nanotubes from local environmental sources. The ARCH Program is overseen by an Administrative Core and is supported by a Facility Core at UTEP.

Nanoindenter (indenting at a scale about thousand times finer than the human hair) is a highly versatile experimental tool for materials characterization that utilizes diamond indenter of 10-20 nanometers in diameter into the surface of materials to determine mechanical properties, including hardness, stiffness, adhesion strength, and wear. It also has the unique ability to rapidly and precisely make several hundred measurements for probing the surface properties of materials. These characteristics make nanoindentation an indispensable tool for research in disciplines ranging from Engineering to Biology, Chemistry, Geology and Medicine. The significance of the project relates to exploring at a fundamental level the mechanical behavior of materials that include the response at high impact, local hardness of thin films for electronic applications, and wear of biomedical implants. Furthermore, the project addresses the challenge of tailoring the surface properties of materials for a host of applications from susceptibility to scratching of electronic devices to adhesion of cells on biomedical implants, providing new directions in the development of next generation of advanced materials with superior mechanical performance and longer life. The project supports nanotechnology education in the Colleges of Science and Engineering at the University of Texas at El Paso and provides practical training to undergraduate and graduate students throughout the campus in a manner that will enable new understanding to emerge at the atomic or molecular level. The compact all-in-one configuration is envisioned to advance the research capabilities of more than 10 research groups, over 45 graduate students, 40 undergraduate students, and 5 post-doctoral researchers, in terms of new understanding at the nano or molecular level, thereby opening entirely new avenues of research in materials science and engineering, and biomaterials and biomedical engineering including the design of nanostructured materials, organic-inorganic hybrid materials, materials for nanoelectronics, and biomedical applications. The research team is committed to disseminate the educational resources on nanoindentation to facilitate broader participation of K-12 audience to scientific and engineering concepts on nanoindentation.

Strength is a fundamental property of the majority of materials systems. Automated, advanced nanoindentation and scratch experiments are appropriately suitable for this challenging task because of high spatial resolution and throughput. The acquisition and subsequent utilization of an automated nanoscale deformation system for materials research at the University of Texas at El Paso constitutes the scope of the project. The goals are to use nanoindention in areas of research that concern deformation mechanisms in nanostructured materials, mechanics of mechanically-induced surface deformation in thin films and polymer nanocomposites, nanomechanical characterization of 3D-printable materials, biomechanical properties of tissue engineered biomaterials including bone, cartilage and skin, adhesion strength of cells, and mechanical properties of ceramic proppants used for hydraulic fracturing. The approach and method involves use of different modules (ultra-low mechanical force, dynamic mechanical analysis, extended z-range, high temperature stage, high load transducer, high resolution imaging, and fluorescence microscope), enabling the researchers to acquire new understanding of the materials at the nanoscale.