Polyconductivity in polypyrrole: the correlated electron glass

p-toluensulfonate doped polypyrrole ~PPy!, undergoes an electric-field induced reversible transition from an insulating state to a highly conductive one. The spatially average field can be as small as 200 V/cm, when the temperature of the sample is below 20 K. The applied electric field leads to a sharp jump in the value of the current to a value which is nearly five orders of magnitude higher than before. When the applied electric field is reduced to below a critical value, the system switches back to a low conductive state. The effect is reversible, symmetric in voltage, and reproducible for different samples. The switching is, we believe, an electronic glass melting transition and it is due to the disordered, highly charged granular nature of PPy.

Comparison of a multiplexed bead-based assay with an immunofluorescence and an enzyme-immuno assay for the assessment of Epstein-Barr virus serologic status.

We have compared a multiplexed bead-based assay (BBA) with an enzyme immunoassay (EIA) and immunofluorescence assay (IFA) for the assessment of the Epstein-Barr virus (EBV) serostatus. Three hundred and ninety-three sera, classified according to IFA results as seronegative (n=100), acute infection (n=100), past infection (n=100) and indeterminate (n=93), were tested by BBA and EIA. Overall, the three methods gave similar results with a relatively high (75.2%) concordance with the consensus interpretation of the serostatus. The most significant discordances were: (i) 58 samples had uninterpretable results for BBA, in majority due to the detection of non-antigen specific antibody binding by control beads. (ii) almost half the samples positive for anti-Epstein-Barr nuclear antigen (EBNA) IgG by BBA or EIA were negative by IFA. Among the latter, only a minority had a history of immunocompromise or treatment, or detectable anti-early antigen antibody. This discrepancy probably reflects a poor sensitivity of IFA for anti-EBNA IgG detection. EIA and BBA had a similar performance and had substantial practical advantages over IFA with respect to testing for EBV serostatus.

The Glass Floor.

A photographic and video record of the project to recreate and reconstruct the glass floor for the opening between the ground and first floors in the rotunda of the Iowa State Capitol. The original glass floor was removed in the early 20th century, but the decision was made to put a new one in to help improve the acoustics and air flow in the building.

Comment on ‘‘Relaxation Kinetics of Nanoscale Indents in a Polymer Glass’’

A Comment on the Letter by A. Knoll, D. Wiesmann, B. Gotsmann, and U. Duerig, published in Physical Review Letter, 2009, vol. 102, p.117801

Investigation of Glass Fiber Composite Dowel Bars for Highway Pavement Slabs, TR-408, 2001

Contractors, engineers, owners and manufacturers want to be certain that a new product or procedure will yield beneficial results when compared to the current method of construction. The following research was conducted in order to compare the performance of epoxy coated dowel bars to dowel bars of alternative shapes and materials such as stainless steel and glass fiber reinforced polymer (GFRP). Research was also done on the effect that dowel bar spacing has on the performance of concrete pavements. Four phases of this research are described in this report.

Developing an Effective Construction Training Program for Hispanic and American Supervisors and Craft Workers, 2007

Hispanics are a large and growing part of the United States workforce. Projections of the U.S. Census Bureau (2001) state that, by the year 2050, Hispanics will account for 25% of the population. For the Midwest in particular, the Hispanic population is expected to increase 35% by the year 2025. The construction industry is expected to experience a greater percentage increase of its Hispanic population, due to the labor-intensive nature of the industry. This study addresses the expected increase of Hispanic workers in the construction industry by testing the best approaches for delivering training to construction crews with Hispanic workers as well as American supervisors and laborers in the state of Iowa. The research methodology consisted of assessing the effects on communication, safety, work environment, and productivity as a result of the integration training. Results show that integration on-site training decreases workers’ desire to move and increases quality of work and productivity. Most importantly, experimental design was used to show the increasing levels of direct construction communication due to the Toolbox Integration Course for Hispanic Workers and American Supervisors (TICHA) designed as part of this project. This study recommends the creation of a quasi-governmental or association program that can offer continuous research and training that can benefit the construction industry as well as society as a whole. The industry involvement in this process is crucial for contractors. Not only do contractors benefit from reduced insurance premiums when workers act safely, but workers with better communication skills are more productive.

Developing an Effective Construction Training Program for American Supervisors with Hispanic Craft Workers, 2005

In the construction industry, Hispanics have the highest rate of fatal work injuries among the racial/ethnic groups, and productivity in the field is limited by the language barrier between Hispanic workers and their supervisors and the level of education of many Hispanic craft workers. This research developed a training program designed to facilitate the integration process between American supervisors and Hispanic craft workers in a practical and cost-effective way, thus improving productivity and lowering fatality rates. The Iowa State University research team conducted a survey of 38 American supervisors, representing 14 Iowa construction companies. Survey results confirm that communication is the main problem experienced by American supervisors in the job site. Many American supervisors also use or depend on a link-person (an individual who interprets tasks to the rest of the Hispanic crew) to communicate to the Hispanic crew members. Research findings show that language differences affect productivity and workplace safety in the construction industry. Additionally, the educational levels of Hispanic workers indicate that they may not have the literacy skills necessary to understand training materials. This research developed two training courses designed to expand the Spanish communication skills of American supervisors. The research team modified the English-as-a-second-language course developed in Phase I into the Spanish as a Second Language (SSL) Survival Course. A series of technical training courses were also developed, titled Concrete Pavement Construction Basics (CPCB), that cover general practices in concrete pavement construction. They are much shorter and more specialized than the SSL course. The CPCB courses provide American supervisors simple and practical communication tools on a variety of topics to choose from according to their specific needs.

Design of a Condition Monitoring System for a Glass Wool Production Line

Työn tarkoituksena oli suunnitella kunnonvalvontajärjestelmä kahdelle lasivillan tuotantolinjalle. Suunnitteluprosessin lisäksi työssä on esitelty erilaisia kunnonvalvontamenetelmiä. Työn alussa on kerrottu erilaisista kunnonvalvontamenetelmistä, joilla voidaan seurata erilaisten laitteiden ja koneiden toimintakuntoa.Erityisesti työssä on tarkasteltu teollisuudessa yleistyviä kunnonvalvonnan värähtelymittauksia. Työssä suunniteltu kunnonvalvontajärjestelmä perustuu viiteen eri menetelmään, jotka ovat värähtelymittaus, lämpötilanmittaus lämpökameralla, lämpötilanmittaus kannettavalla mittarilla, kuuntelu elektronisella stetoskoopilla ja pyörivien osien kunnontarkkailu stroboskoopilla. Kunnonvalvontajärjestelmän suunnittelu on tehty useassa eri vaiheessa. Ensin työssä on kartoitettu tuotannon kannalta tärkeimmät laitteet ja niiden mahdolliset vikaantumistavat. Seuraavaksi on valittu sopivat kunnonvalvontamenetelmät ja tehty mittaussuunnitelma, jossa on esitetty eri laitteille suoritettavat mittaukset ja mittausten aikavälit.Lopuksi työssä on esitelty muutama esimerkkitapaus kunnonvalvontamenetelmien käytöstä sekä kerrottu mahdollisista tulevaisuuden kehitysmahdollisuuksista.

Dynamic arrest in polymer melts: competition between packing and intramolecular barriers

We present molecular dynamics simulations of a simple model for polymer melts with intramolecular barriers. We investigate structural relaxation as a function of the barrier strength. Dynamic correlators can be consistently analyzed within the framework of the mode coupling theory of the glass transition. Control parameters are tuned in order to induce a competition between general packing effects and polymer-specific intramolecular barriers as mechanisms for dynamic arrest. This competition yields unusually large values of the so-called mode coupling theory exponent parameter and rationalizes qualitatively different observations for simple bead-spring and realistic polymers. The systematic study of the effect of intramolecular barriers presented here also establishes a fundamental difference between the nature of the glass transition in polymers and in simple glass formers.

Fiber-reinforced Composite as Oral Implant Material. Experimental studies of glass fiber and bioactive glass in vitro and in vivo

Fiber-reinforced composite as oral implant material: Experimental studies of glass fiber and bioactive glass in vitro and in vivo Department of Prosthetic Dentistry and Biomaterials Science, Institute of Dentistry, University of Turku, Turku, Finland 2008. Biocompatibility and mechanical properties are important variables that need to be determined when new materials are considered for medical implants. Special emphasis was placed on these characteristics in the present work, which aimed to investigate the potential of fiber-reinforced composite (FRC) material as an oral implant. Furthermore, the purpose of this study was to explore the effect of bioactive glass (BAG) on osseointegration of FRC implants. The biocompatibility and mechanical properties of FRC implants were studied both in vitro and in vivo. The mechanical properties of the bulk FRC implant were tested with a cantilever bending test, torsional test and push-out test. The biocompatibility was first evaluated with osteoblast cells cultured on FRC substrates. Bone bonding was determined with the mechanical push-out test and histological as well as histomorplanimetric evaluation. Implant surface was characterized with SEM and EDS analysis. The results of these studies showed that FRC implants can withstand the static load values comparably to titanium. Threaded FRC implants had significantly higher push-out strength than the threaded titanium implants. Cell culture study revealed no cytotoxic effect of FRC materials on the osteoblast-like-cells. Addition of BAG particles enhanced cell proliferation and mineralization of the FRC substrates The in vivo study showed that FRC implants can withstand static loading until failure without fracture. The results also suggest that the FRC implant is biocompatible in bone. The biological behavior of FRC was comparable to that of titanium after 4 and 12 weeks of implantation. Furthermore, addition of BAG to FRC implant increases peri-implant osteogenesis and bone maturation.

Analysis of the process of inspection in recreational craft in Spain. Suggestions for safety improvement

Inspections of pleasure boats in Spain can be carried out by collaborating entities of inspection, entities that must be authorized by the Maritime Administration. This authorization allows to perform effective inspections and technical controls of recreational crafts. Recreational crafts are subjected to surveys that are based on the registration list and on the material used in the hull. In addition, required safety equipment of the recreational boat depends on the distance that the recreational boat is authorized to navigate. Following data obtained from inspections of recreational craft, this paper aims to analyze information about hulls within dry and afloat conditions, about the equipment for rescue and safety, and about other nautical equipment; as well as to perform and improve different verifications during the inspections. All this information points to several aspects relevant for the optimization of the inspection process, the ultimate target being increasing efficiency and effectiveness, and ensuring more safety in recreational craft.

Degradation of the surface of a metasilicate glass due to atmosphere moisture

Glasses with low silica content are very susceptible to suffer pronounced degradation when exposed to room atmosphere during short times. In this work the results of the degradation of the surface of a metasilicate glass with composition 2Na2O.1CaO.3SiO2 are presented. Optical and scanning electron microscopy observations, X-ray diffraction, infrared and Raman microprobe spectroscopic measurements of the modified surface of this glass show strong evidences that it is formed essentially by a crystalline carbonate layer.

Study of the optical properties of TeO2-PbO-TiO2 glass system

We describe the preparation and some optical properties of high refractive index TeO2-PbO-TiO2 glass system. Highly homogeneous glasses were obtained by agitating the mixture during the melting process in an alumina crucible. The characterization was done by X-ray diffraction, Raman scattering, light absorption and linear refractive index measurements. The results show a change in the glass structure as the PbO content increases: the TeO4 trigonal bipyramids characteristics of TeO2 glasses transform into TeO3 trigonal pyramids. However, the measured refractive indices are almost independent of the glass composition. We show that third-order nonlinear optical susceptibilities calculated from the measured refractive indices using Lines' theoretical model are also independent of the glass composition.