Planar Area Research Articles

Partially orthogonal resonators for magnetic resonance imaging

Resonators for signal reception in magnetic resonance are traditionally planar to restrict coil material and avoid coil losses. Here, we present a novel concept to model resonators partially in a plane with maximum sensitivity to the magnetic resonance signal and partially in an orthogonal plane with reduced signal sensitivity. Thus, properties of individual elements in coil arrays can be modified to optimize physical planar space and increase the sensitivity of the overall array. A particular case of the concept is implemented to decrease H-field destructive interferences in planar concentric in-phase arrays. An increase in signal to noise ratio of approximately 20% was achieved with two resonators placed over approximately the same planar area compared to common approaches at a target depth of 10 cm at 3 Tesla. Improved parallel imaging performance of this configuration is also demonstrated. The concept can be further used to increase coil density.

Fractal analysis of single-phase water and polymer solution flow at high rates in open and horizontally displaced rough fractures

A study on the percolation characteristics of single-phase flow in rough fractures at high rates representing hydraulic fracturing conditions is presented. Two-dimensional transparent models of fractures obtained from different rock types (granite, marble and limestone) were reproduced by molding. To represent typical hydraulic fracturing fluids, water and polymeric solutions were injected at a constant flow rate. The inlet pressure was continuously monitored to correlate the permeability changes due to surface roughness of fractures. The fluid distributions were also mapped using the images acquired through the experiments. The surface roughness was quantified using three fractal methods (variogram, power spectral density, and triangular prism) and the ratio of total and planar areas, and these parameters were correlated to the percent wetted areas and pressure drop (i.e., permeability). This exercise was performed on joint type and horizontally displaced (sheared) model fractures.The percentage of planar flow wetted area representing invasion percolation and pressure drop changed remarkably with rock types. Both parameters were controlled by grain size and the surface roughness of fractures. Increasing degree of the roughness caused a decrease in permeability and area wetted by fluid. Models generated from bigger grain size rocks showed more channeling and a lower percentage of fluid wetted areas as well as lower pressure drop (higher permeability). The variogram fractal dimension showed better agreements among other methods for both fluid (water and polymeric solution) and fracture types (joint and horizontally displaced).

QUANTIFYING THE EFFECTS OF FUEL COMPOSITIONS AND PROCESS VARIABLES ON PLANAR SURFACE AREA AND SPRAY NONUNIFORMITY VIA COMBINED MIXTURE-PROCESS DESIGN OF EXPERIMENT

The planar surface area and the spray nonuniformity are important parameters for determining spray evaporation characteristics. In this study, the effects of fuel compositions and two process variables (the injection pressure and axial distance from the measurement plane to the nozzle exit) on both planar surface area and spray nonuniformity were experimentally investigated via statistical extinction tomography. The design of experiment (DoE) was adopted to design the experiment procedure and analyze the data in a systematic way by establishing quadratic mixture models crossed with a linear process model. The planar surface area and the spray nonuniformity were calculated from spatial distributions of surface area density at three measurement planes, which were obtained by using an optical patternator SETSCAN OP-200. The results demonstrated that the axial distance had a significant influence on the planar surface area; whereas, the injection pressure did not show a definite trend for all the test fuels, yet the interaction between the injection pressure and fuel compositions played a noticeable role in determining the planar surface area. The spray nonuniformity was primarily influenced by injection pressure, while it exhibited little dependence on the axial distance. In general, the higher the injection pressure, the higher the spray nonuniformity would be. Fuel composition had an appreciable effect on the spray nonuniformity as well. The DoE-derived models were statistically significant according to analysis of variance analysis, and the optimal values in terms of planar surface area and spray nonuniformity were determined via numerical optimization.

Analysis of a Casting Fracture and Identification of Fatigue From Tire Track Markings

Abstract Knuckle connectors on railcars are required to sustain thousands of cyclic stress events. Manufacturers continue to develop, test, and improve the life of these castings, which are now designed to exceed 400,000 cycles when subjected to tests involving cumulative cyclic sinusoidal load range settings varying between 6800 and 127,000 kgf at room temperature. This paper addressed real-world difficulties of differentiating between component failures due to overload and casting defects, and those that result from fatigue damage. Fatigue fractures in castings are rarely planar and comprise areas where solidification kinetics are different, and locations where porosity or large inclusions are present. The cumulative effect these factors have on fracture is to generate a rough topography, which may exhibit no beachmarks or other outward sign by which a fatigue fracture is commonly recognized. In this paper, an advantage was gained over a field failure because the fracture was produced in a laboratory test. Cycles to failure was recorded and details of the applied cyclic stress were also known. The difficulty regarding scanning electron microscope (SEM) analysis was that classic fatigue features normally visible to the naked eye, such as beachmarks, thumbnail initiation sites and planar areas, were not evident on the fracture face. In addition to documentation of numerous defect features on the fracture surface, SEM analysis revealed a rare but proof-positive form of evidence for propagation of the early stages of fracture by fatigue. The feature has been described in the literature as “tire tracks,” alluding to their similarity to ATV tire impressions or Lunar Rover tracks on the moon. A brief review of earlier literature examples of tire track features is provided, and the generally accepted mechanism for their formation is assessed.

GaAs laser therapy reestablishes the morphology of the NMJ and nAChRs after injury due to bupivacaine

BackgroundLocal anesthetics are used to relieve pre- and postoperative pain, acting on both sodium channels and nicotinic acetylcholine receptors (nAChR) at the neuromuscular junction (NMJ). Bupivacaine acts as a non-competitive antagonist and has limitations, such as myotoxicity, neurotoxicity, and inflammation. Low-level laser therapy (LLLT) has anti-inflammatory, regenerative, and analgesic effects. The aim of the present study was to evaluate the effects of a gallium arsenide laser (GaAs) on the morphology of the NMJ and nAChRs after application of bupivacaine in the sternomastoid muscle. MethodsThirty-two adult male Wistar rats received injections of bupivacaine 0.5% (Bupi: right antimere) and 0.9% sodium chloride (Cl: left antimere). Next, the animals were divided into a Control group (C) and a Laser group (LLLT). The laser group received LLLT (GaAs 904nm, 50mW, 4,8J) in both antimeres for five consecutive days. After seven days, the animals were euthanized and the surface portion of the sternomastoid muscle was removed, frozen, and subjected to morphological and morphometric analyses of the NMJs (nonspecific esterase reaction), confocal laser scanning, and an ultrastructural analysis. The nAChRs were quantified by Western blotting. ResultsIn the chloride group, the morphology and morphometry of the NMJs remained stable. The maximum diameters of the NMJs were lower in the Bupi (15.048±1.985) and LLLT/Bupi subgroups (15.456±1.983) compared to the Cl (18.502±2.058) and LLLT/Cl subgroups (19.356±2.522) (p<0.05). Ultrastructurally, LLLT reduced myonecrosis observed after application of bupivacaine, with recovery in the junctional folds and active zone. There was an increase in the perimeter of the LLLT/Bupi subgroup (150.33) compared to the Bupi subgroup (74.69) (p<0.01) observed by confocal microscopy. There was also an increase in the relative planar area of the NMJ after LBI (8.75) compared to CBupi (4.80) (p<0.01). An analysis of the protein expression of nAChRα1 showed no major differences in the groups studied. There was an increase in protein expression of the ε subunit after application of LLLT (13.055) compared to Bupi (0.251) (p<0.01). Taken together, the present experiments indicate that there was a positive association of the α and γ subunits (p<0.05). ConclusionsThese results demonstrate that LLLT at the dose used in this study reduced structural alterations in the NMJ and molecular changes in nAChRs triggered by bupivacaine, providing important data supporting the use of LLLT in therapeutic protocols for injuries triggered by local anesthetics.

Planar-Based Adaptive Down-Sampling of Point Clouds

Derived point clouds from laser scanners and image-based dense-matching techniques usually include tremendous number of points. Processing (e.g., segmenting) such huge dataset is time-consuming and might not be necessary. For example, a planar surface just needs few points to be defined. In contrast, linear/cylindrical and rough features require more points for reliable modeling since during the data acquisition process, only a portion of linear/cylindrical features is present in the point cloud.This paper introduces an adaptive down-sampling strategy for removing redundant points from high density planar regions while retaining points in planar areas with sparse points and all the points within linear/cylindrical and rough neighborhoods. To demonstrate the feasibility and performance of the proposed procedure, a comparison of segmentation results using original laser and image-based point clouds as well as the adaptively, uniformly, and point-spacing-based down-sampled point clouds are presented while commenting on the computational efficiency and the segmentation quality.

ACME, a GIS tool for Automated Cirque Metric Extraction

Regional scale studies of glacial cirque metrics provide key insights on the (palaeo) environment related to the formation of these erosional landforms. The growing availability of high resolution terrain models means that more glacial cirques can be identified and mapped in the future. However, the extraction of their metrics still largely relies on time consuming manual techniques or the combination of, more or less obsolete, GIS tools. In this paper, a newly coded toolbox is provided for the automated, and comparatively quick, extraction of 16 key glacial cirque metrics; including length, width, circularity, planar and 3D area, elevation, slope, aspect, plan closure and hypsometry. The set of tools, named ACME (Automated Cirque Metric Extraction), is coded in Python, runs in one of the most commonly used GIS packages (ArcGIS) and has a user friendly interface. A polygon layer of mapped cirques is required for all metrics, while a Digital Terrain Model and a point layer of cirque threshold midpoints are needed to run some of the tools. Results from ACME are comparable to those from other techniques and can be obtained rapidly, allowing large cirque datasets to be analysed and potentially important regional trends highlighted.

Equal energy dissipation in wireless sensor network

Wireless sensor network consists of a large number of energy constrained nodes. The lifetime of such a network is limited by the energy dissipated by individual nodes. The important issues are of modeling a sensor network and assessment of its lifetime. This paper gives an analytical framework to establish equal energy dissipation over a network. The equal energy dissipation profile is first obtained for a linear array of wireless sensor nodes and then it is extended for a Y-shaped array of nodes in order to cover a planar area. This approach ensures that all nodes run out of battery energy almost simultaneously. It is shown that the network lifetime almost doubles with the proposed scheme as compared to other reported schemes.

Ultra-miniaturization of a planar amperometric sensor targeting continuous intradermal glucose monitoring

An ultra-miniaturized electrochemical biosensor for continuous glucose monitoring (CGM) is presented. The aim of this work is to demonstrate the possibility of an overall reduction in sensor size to allow minimally invasive glucose monitoring in the interstitial fluid in the dermal region, in contrast to larger state-of-the-art systems, which are necessarily placed in the subcutaneous layer. Moreover, the reduction in size might be a key factor to improve the stability and reliability of transdermal sensors, due to the reduction of the detrimental foreign body reaction and of consequent potential failures. These advantages are combined with lower invasiveness and discomfort for patients. The realized device consists of a microfabricated three-electrode enzymatic sensor with a total surface area of the sensing portion of less than 0.04mm2, making it the smallest fully integrated planar amperometric glucose sensor area reported to date. The working electrode and counter electrode consist of platinum and are functionalized by drop casting of three polymeric membranes. The on-chip iridium oxide (IrOx) pseudo-reference electrode provides the required stability for measurements under physiological conditions. The device is able to dynamically and linearly measure glucose concentrations in-vitro over the relevant physiological range, while showing sufficient selectivity to known interfering species present in the interstitial fluid, with resolution and sensitivity (1.51nA/mM) comparable to that of state-of-art commercial CGM systems. This work can therefore enable less invasive and improved CGM in patients affected by diabetes.

A Structural Dynamic Model Inversion-Based Technique to Characterize Impacts to a Full-Scale and Operational Helicopter Rotor Blade

The incorporation of real-time structural health monitoring has the potential to substantially reduce the inspection burden of advanced composite rotor blades, particularly if impacts can be detected and characterized using operational data. Data-driven impact identification techniques, such as those applied in this work, require that a structural dynamic model of blade frequency response functions (FRFs) be developed for the operational environment. However, the operational characteristics of the rotor system are not accurately described by a model developed and validated in a nonrotating environment. The discrepancies are predominately due to two sources: the change in the blade root boundary condition and the presence of a centrifugal force. This research demonstrates an analytical methodology to compensate for the first of these effects. Derivations of this method are included, as well as analytical and experimental results. Additionally, the theory and experimental results are presented for an approach by which planar impact area and impactor stiffness may be estimated. Applying these techniques, impact location estimation accuracy was improved from 51.6% to 94.2%. Impacts produced by objects of 2–in. diameter were demonstrated to be distinguishable from those of 1 in. or less diameter. Finally, it was demonstrated that the impacts by objects of metallic material were distinguishable from those of rubber material, and that such differentiation was robust to impactor size and impact force magnitude.

Application of a special class of smooth models of the resultant friction force and moment occurring on a circular contact area

Some special cases of a larger class of smooth models of the resultant friction force occurring on a planar contact area are developed and presented. These models are constructed under assumptions of classical Coulomb’s law of friction on each element of contact and instantaneous transition between two modes: fully developed sliding and rigid stick state without local slips and deformations of the contact area. They are able to model cases of different values of static and kinetic friction factors. The considered models are very effective tools for fast and reliable numerical simulations of mechanical systems with frictional contacts. They are applied in modelling and numerical analysis of a special kind of mechanical system, i.e. a kind of a pendulum with special frictional driving. The rotational joint of the pendulum is elastically suspended in the motion plane. The pendulum is driven by circular frictional contact with a rotating disk. Examples of self-excited bifurcation and chaotic dynamics as well as stick–slip behaviour of the pendulum are presented.

Distribution of igneous rocks in China revealed by aeromagnetic data

After several decades of aeromagnetic surveys, the measured data now cover nearly the entire Chinese continent and part of the China Sea. These data were first applied in this research and could provide important insights into the distribution of igneous rocks beneath the earth’s surface. Because different types of igneous rocks have a magnetic difference and produce distinct aeromagnetic anomalies on aeromagnetic ΔT image with reduction to the pole or other data calculating maps. By analyzing more than 240 thousand magnetic susceptibility data points and aeromagnetic anomalies of known igneous rocks in the Chinese continent, it was determined that mafic-ultramafic rocks commonly have a high magnetic susceptibility and cause linear and strong positive aeromagnetic anomalies. Intermediate-felsic rocks have a stable and low magnetic susceptibility and show a flat gradient variation and regular shape. Volcanic rocks have large variability in regard to magnetic susceptibility and romance; therefore, the aeromagnetic anomalies are always random or show variation within a planar area and decrease rapidly when an upward continuation is applied. Following the aeromagnetic data and calculating the maps of the vertical first order derivative and the tilt derivative, and combining this information with known outcrops of igneous rocks, we renewed the boundaries of 82 known mafic-ultramafic rocks, 228 known intermediate-felsic rocks and 131 known volcanic rocks. In addition, we newly mapped concealed igneous rocks of 203 mafic-ultramafic rocks, 2322 intermediate-felsic rocks and 494 volcanic rocks. The igneous rocks can be identified as nine ultra-mafic belts, 10 mafic belts (or regions), 27 intermediate-felsic belts and eight volcanic blocks. The results indicate that the mafic-ultramafic rocks are mainly distributed in Tibet, Erenhot of Inner Mongolia and northern Qilian and the smaller zones in the western Kunlun, Tianshan, western Junggar, eastern Tibet, Maqin in Gansu and the Ailao Mountain (Mtn.) areas. The mafic rocks are mostly outcropped in northern Tibet, southwestern Sanjiang, Kangdian in Sichuan, Baise and Rongjiang in Guangxi, Yinjiang in Guizhou, Dabashan Mtn., Southern Dabie Mtn, Bangbu in Anhui, Qiemo in Xinjiang. The intermediate-felsic rocks are mainly located in the orogenic system and rarely within the craton. Volcanic rocks are widely developed in eastern and western China such as the circumference of Songliao Basin, Erlian Basin, the southern Yellow Sea - Subei Basin, Bohai Bay Basin, eastern Zhejiang, the circumference of Hainan Island, southern Sichuan - northern Yunan, central Tibet, the Bachu area in Tarim Basin, Junggar Basin and Turpan-Hami Basin.

Continuous Road Network Generalization throughout All Scales

Until now, road network generalization has mainly been applied to the task of generalizing from one fixed source scale to another fixed target scale. These actions result in large differences in content and representation, e.g., a sudden change of the representation of road segments from areas to lines, which may confuse users. Therefore, we aim at the continuous generalization of a road network for the whole range, from the large scale, where roads are represented as areas, to mid- and small scales, where roads are represented progressively more frequently as lines. As a consequence of this process, there is an intermediate scale range where at the same time some roads will be represented as areas, while others will be represented as lines. We propose a new data model together with a specific data structure where for all map objects, a range of valid map scales is stored. This model is based on the integrated and explicit representation of: (1) a planar area partition; and (2) a linear road network. This enables the generalization process to include the knowledge and understanding of a linear network. This paper further discusses the actual generalization options and algorithms for populating this data structure with high quality vario-scale cartographic content.

From Clothing to Laundry Water: Investigating the Fate of Phthalates, Brominated Flame Retardants, and Organophosphate Esters.

The accumulation of phthalate esters, brominated flame retardants (BFRs) and organophosphate esters (OPEs) by clothing from indoor air and transfer via laundering to outdoors were investigated. Over 30 days cotton and polyester fabrics accumulated 3475 and 1950 ng/dm(2) ∑5phthalates, 65 and 78 ng/dm(2) ∑10BFRs, and 1200 and 310 ng/dm(2) ∑8OPEs, respectively. Planar surface area concentrations of OPEs and low molecular weight phthalates were significantly greater in cotton than polyester and similar for BFRs and high molecular weight phthalates. This difference was significantly and inversely correlated with KOW, suggesting greater sorption of polar compounds to polar cotton. Chemical release from cotton and polyester to laundry water was >80% of aliphatic OPEs (log KOW < 4), < 50% of OPEs with an aromatic structure, 50-100% of low molecular weight phthalates (log KOW 4-6), and < detection-35% of higher molecular weight phthalates (log KOW > 8) and BFRs (log KOW > 6). These results support the hypothesis that clothing acts an efficient conveyer of soluble semivolatile organic compounds (SVOCs) from indoors to outdoors through accumulation from air and then release during laundering. Clothes drying could as well contribute to the release of chemicals emitted by electric dryers. The results also have implications for dermal exposure.

ПАРАТИПИЧЕСКАЯ ИЗМЕНЧИВОСТЬ ПЕРИОДА ВСХОДЫ–КОЛОШЕНИЕ ЯЧМЕНЕЙ ДАГЕСТАНА

For three years 265 barley accessions from Dagestan were analyzed for the duration of the period between shooting and earing stages. Under the conditions of south planar area of Dagestan, the early accessions k-15008 and k-15013 have been selected. The accession k-15027 was characterized by a high rate of development in the Northwestern area of the country. The Dagestanian barleys were found to be strongly affected by the growing conditions, notably they have a high norm of reaction. It is concluded that vernalization temperatures, short day and high temperatures during the vegetation period promote earliness of barley.

Quantitative and visual analysis of proppant transport in rough fractures

The consensus reached in the literature is that the roughness of fractures plays a crucial role on proppant transport affecting the aperture sustainability and conductivity of hydraulic fractures. To clarify this, an experimental scheme and analysis are presented in this paper. Propping agents were introduced into seven different transparent fracture replicas obtained from different origin rock samples (granite, marble, and limestone) at a high rate mimicking hydraulic fracturing process conditions. The inlet pressure was continuously monitored to quantify the change in hydraulic conductivity due to proppant distribution. Corresponding images were collected to trace the transport of proppants and their behavior was correlated to the measured pressure drop (representing conductivity) change. Experiments were repeated on joint (perfectly mating) and horizontally displaced (sheared-unmating) models using water and polymer solution.Existing closure areas controlled by roughness dictated proppant movement and the change in hydraulic conductivity significantly in both joint and displaced type fractures. To quantify this effect, pressure drop across the model and proppant distribution (area saturated with sands) were correlated to three fractal methods (variogram, power spectral density, and triangular prism) and the ratio of total and planar fracture surface areas. Correlation parameters and types differ for water and polymer solution. Joint and displaced type fractures also showed differences in hydraulic conductivity change and sand distribution for certain type of rocks, especially at the higher variogram fractal dimensions.

Mifepristone is a Vasodilator Due to the Inhibition of Smooth Muscle Cells L-Type Ca2+ Channels.

Derived from the estrane progestins, mifepristone was the first synthetic steroid of this class employed as abortifacient in the first months of pregnancy. Mifepristone reduces high potassium-induced contraction and prevents calcium-induced contraction. At the vascular level, mifepristone induces direct relaxation in rat and human arteries, and this effect seems to be endothelium- and NO independent, suggesting that the vascular smooth muscle is its target. Moreover, mifepristone's effect could involve the modulation of different calcium channels. The aim of the present study is to analyze the involvement of calcium channels in the relaxation induced by mifepristone on vascular smooth muscle cells (VSMCs). Planar cell surface area (PCSA) technique was used to analyze the effect of mifepristone on the VSMC contractility, and the whole cell configuration of patch-clamp technique to measure the activity of L-type Ca(2+) channels (LTCC) in A7r5 cells. Regarding the PCSA technique, mifepristone induced relaxation of the VSMC previously contracted by different agents. Also, a rapid inhibitory effect on basal and BAY K8644-stimulated calcium current was observed, which indicates that this drug has the ability to block LTCC. These results suggest that mifepristone induces relaxation on the VSMCs due to the inhibition of the calcium channels.

Nanomechanics of phospholipid bilayer failure under strip biaxial stretching using molecular dynamics

The current study presents a nanoscale in silico investigation of strain rate dependency of membrane (phospholipid bilayer) failure when placed under strip biaxial tension with two planar areas. The nanoscale simulations were conducted in the context of a multiscale modelling framework in which the macroscale damage (pore volume fraction) progression is delineated into pore nucleation (number density of pores), pore growth (size of pores), and pore coalescence (inverse of nearest neighbor distance) mechanisms. As such, the number density, area fraction, and nearest neighbor distances were quantified in association with the stress–strain behavior. Deformations of a 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) bilayer were performed using molecular dynamics to simulate mechanoporation of a neuronal cell membrane due to injury, which in turn can result in long-term detrimental effects that could ultimately lead to cell death. Structures with 72 and 144 phospholipids were subjected to strip biaxial tensile deformations at multiple strain rates. Formation of a water bridge through the phospholipid bilayer was the metric to indicate structural failure. Both the larger and smaller bilayers had similar behavior regarding pore nucleation and the strain rate effect on pore growth post water penetration. The applied strain rates, planar area, and cross-sectional area had no effect on the von Mises strains at which pores greater than 0.1 nm2 were detected (0.509 ± 7.8%) or the von Mises strain at failure (εfailure = 0.68 ± 4.8%). Additionally, changes in bilayer planar and cross-sectional areas did not affect the stress response. However, as the strain rate increased from 2.0 × 108 s−1 to 1.0 × 109 s−1, the yield stress increased from 26.5 MPa to 66.7 MPa and the yield strain increased from 0.056 to 0.226.

Research on the architecture of submarine-fan lobes in the Niger Delta Basin, offshore West Africa

As one of the most important reservoirs in submarine fan, submarine lobes are hot fields for the deep-water oil–gas exploration in the world. Although a large amount of researches have been carried out on the architecture model of submarine lobes throughout the world, some controversies still exist on aspects such as the differential distribution of composite patterns and the quantitative relationships among different sedimentary settings. This paper, which took an oilfield in the Niger Delta Basin offshore West Africa as an example and utilized abundant core, well-logging and seismic data comprehensively, established the semi-quantitative to quantitative architecture model for individual lobe and lobe complex.Results show that (1) A lobe complex was composed of multiple individual lobes as the compensational stacking pattern. According to the stacked relationship among individual lobes, four types of compensational stacking pattern were classified as the inordered type, the lateral migration type, the retrograding type and the prograding type. Influenced by the laterally confined degree of palaeotopography, the basin floor fan lobe complex was easily superimposed as inordered type, showing relatively large lateral width but relatively small thickness; the slope fan lobe complex was easily superimposed as lateral migration, retrograding and prograding types, showing relatively small lateral width but relatively large thickness. (2) Influenced by the laterally confined degree of palaeotopography, the basin floor fan individual lobes showed relatively large planar distribution area but relatively small thickness, while the slope fan individual lobes showed relatively small planar distribution area but relatively large thickness. An individual lobe was composed of multiple lobe stories by the way of aggradation–progradation pattern. From proximal to middle and distal part of individual lobes, the bottom mass-transport-deposits and the top branch channels disappeared gradually, and the amalgamated degree of the middle tabular sandbodies weakened as well with gradually developing of muddy interlayers. The formation of an individual lobe generally includes three stages as “rapid accumulation–progradation–aggradation”.

Characterizing the sorption of polybrominated diphenyl ethers (PBDEs) to cotton and polyester fabrics under controlled conditions

Cotton and polyester, physically and chemically different fabrics, were characterized for sorption of gas-phase polybrominated diphenyl ethers (PBDEs). Scanning electron microscopic (SEM) images and BET specific surface area (BET-SSA) analysis showed cotton's high microsurface area; NMR analysis showed richness of hexose- and aromatic-carbon in cotton and polyester, respectively. Cotton and polyester sorbed similar concentrations of gas-phase PBDEs in chamber studies, when normalized to planar surface area. However, polyester concentrations were 20–50 times greater than cotton when normalized to BET-SSA, greater than the 10 times difference in BET-SSA. The difference in sorption between cotton and polyester is hypothesized to be due to ‘dilution’ due to cotton's large BET-SSA and/or greater affinity of PBDEs for aromatic-rich polyester. Similar fabric-air area normalized distribution coefficients (K'D, 103 to 104m) for cotton and polyester support air-side controlled uptake under non-equilibrium conditions. K'D values imply that 1m2 of cotton or polyester fabrics would sorb gas-phase PBDEs present in 103 to 104m3 of equivalent air volume at room temperature over one week, assuming similar air flow conditions. Sorption of PBDEs to fabrics has implications for their fate indoors and human exposure.