ForceSpinning of polyacrylonitrile for mass production of lithium‐ion battery separators

We present results on the Forcespinning^® (FS) of Polyacrylonitrile (PAN) for mass production of polymer nanofiber membranes as separators for Lithium‐ion batteries (LIBs). Our results presented here show that uniform, highly fibrous mats from PAN produced using Forcespinning^®, exhibit improved electrochemical properties such as electrolyte uptake, low interfacial resistance, high oxidation limit, high ionic conductivity, and good cycling performance when used in lithium ion batteries compared to commercial PP separator materials. This article introduces ForceSpinning^®, a cost effective technique capable of mass producing high quality fibrous mats, which is completely different technology than the commonly used in‐house centrifugal method. This Forcespinning^® technology is thus the beginning of the nano/micro fiber revolution in large scale production for battery separator application. This is the first time to report results on the cycle performance of LIB‐based polymer nanofiber separators made by Forcespinning^® technology. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132, 42847.     

Partitioning spectral absorption in case 2 waters: discrimination of dissolved and particulate components

A series of three mathematical procedures is derived to discriminate the light absorption by phytoplankton, colored dissolved organic matter, and nonpigmented particulates in waters in which absorption is dominated by factors other than phytoplankton (i.e., case 2 waters). The procedures utilize normalized absorption cross-sectional spectra of the absorption components and matrix inversion to solve for the coefficients that scale the normalized spectra. The procedures differ in the amount of ancillary measurements incorporated to reduce the variability of the estimates. The procedure that incorporates no ancillary information is expected to be unbiased only over long time periods. Application of the procedures to a 15-day time series of continuously monitored data from the Rhode River, Maryland, revealed the presence of large (approximately twofold) changes in absorption at 440 nm over periods of a few hours. Hourly sampling over a 24-h period confirmed that the changes in measured optical coefficients corresponded to changes in water quality. Errors in estimates of absorption components were of a magnitude consistent with those observed in development of the procedures and confirmed the progressive improvement achieved by incorporation of additional information. Over the time period observed, changes in optical properties appeared to be driven by advective processes.     

Incident solar radiation on Argentina from the geostationary satellite GOES: Comparison with ground measurements

Daily values of the solar radiant energy incident on earth's surface constitute a quantity of increasing importance, not only in nonconventional energy development but also for agricultural, weather, and climate monitoring and predictions. In Argentina, the solar global radiation has been measured since 1978 through a network of pyranometers distributed all over the country. Simultaneously, in the area limited by 21° and 41°S latitude and 53° and 67°W longitude, insolation determinations have been made using the geostationary satellite GOES from May 1982 to June 1984. Therefore, it was possible to compare the simultaneous hourly and daily values of solar global radiation corresponding to the northern part of the country during 1982 and 1983. In this article, the results of the comparison are presented. It is shown that the standard error of the satellite-derived hourly and daily insolation values when compared against pyranometers is about 25%, and in the range of 15 to 20% of the mean values, respectively. Therefore, operational estimation of surface insolation in the region using GOES data appears normally feasible.     

Extraction and characterization of soluble protein fractions from Phaseolus lunatus L seeds

Legume proteins as a potential source of valuable nutrients, are the object of several studies in order to obtain the best use. A basic knowledge becomes more important for those proteins from species not wholly utilized, before using them as food ingredients. The objective of this work was to determine several structural and nutritional characteristics of the protein fractions from Phaseolus lunatus, separated in different solvents. The relative amount of extraction for the albumins (ALB), globulins (GLB), prolamines (PRL), and glutelins (GLT) was 62.3, 34.8, 1.4 and 1.5%, respectively. The SDS-PAGE electrophoretic profile of both ALB and GLB, showed seven common bands in intervals from 10 to 95 kDa, and 14 to 99 kDa, respectively; the amino acids profile showed that PRL was the rich fraction in sulfurated amino acids (11.5 g/100 g protein); the content of lysine in the fraction of ALB was smaller than expected but the requirement of the FAO in the fractions of GLB and GLT was covered. In general, the fraction of GLB had the best balance of amino acids and digestibility (80%); however, it had a relationship of calculated protein efficiency ratio (C-PER) of 0.11, smaller than the ratio in ALB (0.97). The calorimetric analysis showed denatured temperatures around 90 degrees C for the ALB, GLB, and GLU fractions. The PRL fraction probably did not present a thermal transition because the proteins were denaturalized by the extraction conditions.     

Potential effects in multi-resolution post-classification change detection

Change detection is one of the primary applications of remote-sensing data, and many techniques have been developed during the past three decades. Although frequently criticized and despite many alternatives, due to its simplicity and intuitive manner, post-classification change detection still remains one of the most applied techniques. Many studies in the field of change detection analysis acknowledge, for instance, the impact of misregistration, inconsistencies in classification schemes or differences in methods for image interpretation. However, there are additional, rarely studied influences that can cause large errors in change detection results, including integrating multi-resolution data, the adjacency effect and the minimum mapping units (MMUs) that are applied to the classification before change detection. This study demonstrates these effects for the complex land cover of the Alvarado mangrove area at the Mexican Gulf Coast, employing 10 m Système Pour l'Observation de la Terre 5 (SPOT-5) high geometric resolution (HRG)‐based and 57 m Landsat Multispectral Scanner (MSS) classifications. As a baseline, the proportion of the fine spatial resolution classes within the coarse spatial resolution cells were derived, from which proportional change matrices were computed. The analysis employs difference measures to compare change matrices and proportional maps. The impact of various tested resampling functions was negligible if coarse resolution data were refined. For coarsening fine spatial resolution data, change matrix comparison was comparatively small but yielded differences of approximately 20% in spatially explicit measures. Incorrect positional alignment indicated differences of up to 5% in the change matrix for a misregistration of 100 m and even higher spatially explicit differences (28%). The discrepancies due to the adjacency effect were rather low. MMUs of 25 ha resulted in differences of up to 36% in the change matrix. The magnitude of the discrepancies of all studied effects depends on the class diversity in the map, and some can also be related to the difference in spatial resolution.     

The Separation and Identification of Higher Molecular Weight Fullerenes

A nonaqueous, reversed-phase separation of the fullerenes is described. The bonded-phase, a polymeric octadecyl one, has previously been shown to have a very large separating power for nonplanar polycyclic aromatic hydrocarbons. This work shows that this shape selectivity also is found with the fullerenes, allowing very short retention times while maintaining separation of the C₆₀ and C₇₀ species. Additionally, a fraction containing larger fullerenes was isolated. UV absorbance spectra of these species were obtained. Preliminary spectra of hydrogen chemical ionization mass spectra were also obtained and showed that the fullerenes adsorb large amounts of molecular hydrogen.     

Processing,rheology, and storage stability of recycled EVA/LDPE modified bitumen

The optimum processing conditions for the manufacture of polymer‐modified bitumens (PMBs), as well as the rheological properties of the final polymer‐bitumen blends, strongly depend on the characteristics of the mixing device used. The present work is focused on the comparison among the kinetics of the mixing process and the rheological properties and microstructural characteristics of PMBs manufactured in two different mixers. Thus, blends of 60/70 penetration grade bitumen and recycled EVA/LDPE were processed in both high and low‐shear devices. Knowledge on the evolution of shear viscosity and microstructure with time, as well as on the mechanical properties of the final polymer‐bitumen blends, was gained from rheological and modulated DSC tests, and optical microscopy. The results obtained demonstrate that processing in the high‐shear device yields a significant decrease in the time needed for the polymer‐bitumen blend to reach the final stage of the manufacturing process, as well as an important reduction in bitumen oxidation and enhanced properties in a wide range of in‐service temperatures. However, polymer‐bitumen blends manufactured in the high‐shear device are not stable during its storage at high temperature. POLYM. ENG. SCI., 47:181–191, 2007. © 2007 Society of Plastics Engineers     

Bitumen modification with a low-molecular-weight reactive isocyanate-terminated polymer

A low-molecular-weight polyethyleneglycol functionalized with a polymeric MDI (4,4′-diphenylmethane diisocynate) was used as a modifying agent for a 60/70 penetration grade bitumen. The rheological properties of the resulting modified binder, at both low and intermediate temperatures, before and after curing at room temperature were studied and compared with those corresponding to a SBS modified bitumen. The analysis showed that the addition of a small quantity of this reactive polymer leads to enhanced rheological properties mainly at high in-service temperature (50 °C). However, modification was found to be rather slow during binder curing at room temperature. Moreover, storage stability analysis showed that phase separation did not take place after bitumen storage at 163 °C, though storage at high temperature affects the modification capability of the reactive polymer. Atomic force microscopy measurements showed that the reactive polymer addition leads to asphaltene-rich regions with lower thermal susceptibility, which are present even at high temperature, yielding an improved bitumen viscosity in this range of in-service temperatures.     

Effect of processing on the rheological properties of poly-urethane/urea bituminous products

In this work, bitumen modification, by “in situ” formation of poly-urethane/urea-based polymers in the bituminous matrix, has been studied. This procedure consisted of a first modification by the addition of MDI-PPG reactive prepolymer (polypropylene-glycol, PPG, functionalized by polymeric MDI, 4,4′-diphenylmethane diisocyanate), in a first stage, and a further modification of the new bitumen-MDI-PPG molecules as water was added, in a second stage. Thin layer chromatography, TLC-FID, and infrared spectroscopy, FTIR, techniques have been used to follow the reactions occurring in four different types of bitumen. Rheological measurements have demonstrated that the resulting bitumen modification strongly depends on the processing conditions selected during the first stage. Thus, bitumen modification degree after water addition increases as processing time does. Furthermore, water addition has been found to promote bitumen foaming at low processing temperatures, which could be used in novel applications where a foamed binder is required. As a result, a reactive bitumen modification mechanism, involving a set of three chemical reactions, has been proposed.