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Herein, we demonstrate an electrogenerated porous iodine interphase with positively charged (e.g., protonated in an aqueous acidic medium) electrolyte channels on a Pt ultramicroelectrode (UME) that stimulates in situ electrokinetic transport of I−, resulting in a significant enhancement of anodic current associated with electro-oxidation of I− in an aqueous medium. Our scientific findings would be critical for developing various 'fast charging' I−-based aqueous rechargeable batteries. The cyclic voltammograms (CVs) obtained using a 10 mM I− + 1 M HClO4 solution represent the electro-oxidation of I− to I2via I3− and precipitation of solid I2 on the electrode due to its limited solubility under the conditions in which the mass transport of I− was mainly governed by diffusion. However, as the I− concentration increased to 1 M, the voltammetric behavior for oxidation of I− deviated from the previously reported electrode reaction model. The abnormal voltammogram became explicit as the concentration of HClO4 increased to 4 M or higher, showing a linear increase in the overlimiting anodic current as the electrode potential was positively biased. In addition, the formation of protonated iodine, I2(H+)n, was estimated from the onset of a potential shift in the negative direction with increasing bulk H+ concentration in the solution. Molecular dynamics (MD) simulations demonstrated feasible porous iodine structures with electrolyte channels in an aqueous solution containing both I2 and HClO4. Voltammetric and MD simulation analyses suggested the electrogeneration of a porous I2(H+)n interphase with positively charged electrolyte channels on the Pt UME, which stimulates in situ electrokinetic transport of I− through the channels. This was supported by finite element analyses of the transport of I− through a simplified model channel with a positively charged surface, which demonstrated a linearly increased I− flux as a function of a positively biased electrical potential difference between the electrode and the entrance of the channel. In addition, we observed that the electrokinetic phenomena occurring during the electro-oxidation of I− also occurred in aqueous media containing other electrolytes (e.g., NaClO4). The slope of the voltammetric curve and the maximum value of the observed electrokinetic current due to electro-oxidation of I− in HClO4 were higher than those in NaClO4 solution because of higher positive surface charge density of the porous iodine interphase in the aqueous medium containing HClO4 than that containing NaClO4. Chronoamperometric analysis revealed the transient phase transition region where an effective porous I2(H+)n interphase was formed from its disconnected clusters that contributed to the electrokinetic I− current. In addition, it showed that the structure of the I2(H+)n interphase would be stable for electrokinetic transport of I−. Based on our analyses, we provide a more detailed mechanistic picture of the electro-oxidation of I− to I3−via an I2 interphase in an aqueous acidic medium with the following phase transition of I2: I2(H+)n cluster → porous I2(H+)n stimulating electrokinetic transport of I− → dense I2 with an I−-insulating nature. [ABSTRACT FROM AUTHOR]

Buildings in modern society tend to gradually expand in size due to technological development and overcrowding, which increases the risk of fire. Therefore, continuous efforts are being made to ensure the evacuation safety of occupants by installing firefighting facilities and using flame retardant building finishing materials. This study aims to present a fire performance evaluation plan for building finishing materials using simulations and identify risks that arise from not using flame retardant building finishing materials in medical facilities with vulnerable occupants. A control group for fire performance evaluation was selected using polyurethane foam, while two types of cellulose-based building finishing materials with different flame retardants were chosen for analysis. The cellulose-based finishing materials included expanded graphite, magnesium hydroxide, montmorillonite, and ammonium polyphosphate. Fire performance was evaluated using FDS and path detector simulations based on NES 713 and ISO 5660-1. The results of the study showed that there was a difference of three people in the prediction of the number of deaths depending on the scope of analysis, and it was confirmed that the toxic gas detected was different depending on the added flame retardant. Additionally, construction finishing materials with flame retardant performance increased ASET by at least 130 s compared to polyurethane foam, and the evacuation safety exceeded 1, confirming the effectiveness of securing evacuation stability for occupants. [ABSTRACT FROM AUTHOR]

An additive, 1,4‐butadiene sulfone (BDS), which generates H2SO3 by in situ thermal retro‐Diels‐Alder decompositions, is used for preparing high β‐phase polyvinylidene fluoride (PVDF) films. Because of preferential multiple non‐covalent interactions of H2SO3 with all‐trans configuration of PVDF, β‐phase PVDF is spontaneously induced without mechanical drawing and/or extensive thermal annealing process. PVDF films cast from PVDF/BDS/water solutions exhibit high β‐phase content (fβ = 95%) when the BDS concentration is only cBDS = 1.0 wt%, which is confirmed by polarized optical microscopy (POM), SEM, Fourier transform infrared spectroscopy (FT‐IR), differential scan calorimetry (DSC), and 2D grazing incidence wide‐angle X‐ray scattering (GIWAXS). Because of the high β‐phase content, PVDF films prepared by using BDS exhibit excellent ferroelectric and piezoelectric properties (Ec = 50 MV/m, Pr = 5 µC/cm2, and d33 = ≈‐25 pm/V). Furthermore, a triboelectric nanogenerator (TENG) developed with high β‐phase PVDF film exhibits enhanced performance as 2.5 times higher than neat PVDF film in output charge density, allowing reliable operation of conventional electronic devices. [ABSTRACT FROM AUTHOR]

As part of the validation effort to evaluate the consistency of a new cold in-place recycling using foamed asphalt (CIR-foam) mix design process for the Iowa Department of Transportation, the dynamic modulus and repeated load tests were conducted to evaluate the performance characteristics of CIR-foam mixtures over a wide range of loading and temperature conditions. The main objective of this research is to study the impacts of the foamed asphalt contents and reclaimed asphalt pavement (RAP) material characteristics on dynamic modulus and flow number. Dynamic modulus and repeated load tests were conducted on CIR-foam mixtures with RAP materials collected from seven different CIR project sites located throughout Iowa. Dynamic modulus values of the RAP materials varied depending on the sources and foamed asphalt contents. Coarse RAP materials with a small amount of residual asphalt content exhibited a higher modulus value at 4.4[degrees]C but exhibited a lower dynamic modulus value at 37.8[degrees]C than fine RAP materials with a large amount of residual asphalt content. Flow numbers were varied significantly depending on their RAP sources and foamed asphalt contents. Fine RAP materials with a hard residual asphalt binder exhibited a higher flow number than coarse RAP materials with a soft residual binder. The relative rankings of RAP materials in terms of the flow number did not change when the foamed asphalt was increased from 1.0 to 3.0%, which supports the repeated load test being consistent in evaluating a rutting potential of RAP materials. CE Database subject headings: Recycling; Asphalt pavements; Mixtures; Foam.

The main objective of this study is to validate a new mix design procedure for cold in-place recycling using foamed asphalt (CIR-foam) developed for the Iowa Department of Transportation. First, reclaimed asphalt pavement (RAP) materials were collected from seven different CIR construction sites located across the state of Iowa. To determine the consistency of a new CIR-foam mix design procedure, the mix design was performed seven times using these RAP materials. The test specimens were prepared using gyratory compactor rather than Marshall hammer because it produced more consistent mixtures for various foamed asphalt contents and curing conditions. The indirect tensile strength test was performed on the vacuum-saturated specimens prepared using each of seven RAP material sources for five different foamed asphalt contents (1.0, 1.5, 2.0, 2.5, and 3.0%), given a fixed moisture content of 4.0%. As the foamed asphalt content increased from 1.0 to 3.0% at 0.5% increments, air voids in the CIR-foam mixtures decreased gradually. The indirect tensile strength of CIR-foam specimens cured for two days at 60[degrees]C was significantly higher than that of CIR-foam specimens cured for three days at 40[degrees]C. Based on the new mix design procedure, the optimum foamed asphalt contents were consistently found at values between 1.5 and 2.5% for all seven different RAP materials. The stiffer residual asphalt required more foamed asphalt, whereas the higher residual asphalt content did not require a smaller amount of foamed asphalt. The raveling test result was very sensitive to the curing time and the foamed asphalt content, such that RAP materials with a large amount of stiff residual asphalt would exhibit more potential for raveling. DOI: 10.1061/(ASCE)0899-1561(2007)19:11(1000) CE Database subject headings: Recycling; Asphalt pavements; Mixtures; Tensile strength.

The main objective of this study is to determine mix design parameters for cold in-place recycling with foamed asphalt. First, the foaming process of laboratory foaming equipment was validated by varying the water and asphalt content. 1.3% water content was adopted to create the optimum foaming characteristics in terms of the expansion ratio and the half-life at 170[degrees]C under air pressure of 400 kPa and water pressure of 500 kPa. The mix design was then performed using both the indirect tensile test and the Marshall test for 13 combinations of foamed asphalt content and water content for three different gradations. The water content did not appear to affect the test results significantly. Maximum stability (both wet and dry samples), maximum bulk density, and indirect tensile strength (both wet and dry samples) were all obtained around 2.5% foamed asphalt content. Overall, the highest Marshall stability and redirect tensile strength were obtained in the order of line, field, and coarse reclaimed asphalt pavement gradations. It is recommended that the indirect tensile strength based on wet samples be adopted for determining the optimum foamed asphalt content. DOI: 10.1061/(ASCE)0899-1561(2006)18:1(116) CE Database subject headings: Recycling; Asphalt mixes; Asphalt pavements; Tensile strength.