Mixing rules and unlike interaction parameter correlations for characterization parameters in a three-parameter corresponding-states thermodynamic properties correlation.

The conformal solution method is used as the basis for developing mixing rules for the characteristic parameters appearing in a three-parameter, corresponding-states correlation of thermodynamic properties. A logical extension of the van der Waals (VDW) one-fluid rules from two to three parameters, referred to herein as the modified VDW one-fluid mixing rules, is shown to yield accurate predictions of vapor-liquid equilibrium (VLE) for binary mixtures of paraffin hydrocarbons with similar size molecules but poor VLE predictions for mixtures of paraffin hydrocarbons with highly dissimilar molecular sizes. Therefore, semiempirical exponent mixing rules were developed to obtain improved VLE predictive capability. In order to predict unlike interaction parameters from the characteristic properties of pure components alone, new correlations were formulated. The semiempirical exponent mixing rules, in conjunction with the correlations developed herein for unlike interaction parameters, gave predicted VLE accuracy standing about in the middle between the modified VDW one-fluid and semiempirical exponent mixing rules using individual unlike interaction parameters for each pair of paraffin hydrocarbons. The overall average absolute deviation of predicted methane K-values from experimental binary mixture data for methane with heavier normal paraffin hydrocarbons ranging from ethane through normal decane was 4.1% using the semiempirical exponent mixing rules compared with 11.0% for the modified VDW one-fluid rules (both using individual unlike interaction parameters for each fluid pair) and 7.78% for the semiempirical exponent mixing rules using the correlations for unlike interaction parameters. The three methods provide accurate predictions of bulk properties for the methane binaries. When tested for other light hydrocarbons and natural gas mixtures, the semiempirical exponent mixing rules show significantly better accuracy for VLE predictions for multicomponent mixtures involving light hydrocarbons, slightly better accuracy for binary mixtures involving light hydrocarbons and nitrogen and comparable accuracy for binary and multicomponent mixtures containing hydrogen sulfide and carbon dioxide (when compared to the modified VDW one-fluid mixing rules). Both mixing rules exhibit reasonably accurate predictions of VLE and bulk properties for these systems. The semiempirical exponent mixing rules with the correlations for unlike interaction parameters yield acceptable predictions of VLE and bulk properties for all mixtures studied except the hydrogen sulfide-carbon dioxide and ethane-ethylene systems

A Patterned Single Layer Graphene Resistance Temperature Sensor

Micro-fabricated single-layer graphenes (SLGs) on a silicon dioxide (SiO2)/Si substrate, a silicon nitride (SiN) membrane, and a suspended architecture are presented for their use as temperature sensors. These graphene temperature sensors act as resistance temperature detectors, showing a quadratic dependence of resistance on the temperature in a range between 283 K and 303 K. The observed resistance change of the graphene temperature sensors are explained by the temperature dependent electron mobility relationship (~T−4) and electron-phonon scattering. By analyzing the transient response of the SLG temperature sensors on different substrates, it is found that the graphene sensor on the SiN membrane shows the highest sensitivity due to low thermal mass, while the sensor on SiO2/Si reveals the lowest one. Also, the graphene on the SiN membrane reveals not only the fastest response, but also better mechanical stability compared to the suspended graphene sensor. Therefore, the presented results show that the temperature sensors based on SLG with an extremely low thermal mass can be used in various applications requiring high sensitivity and fast operation

Recent Advances in Unconventional Lithography for Challenging 3D Hierarchical Structures and Their Applications

In nanoscience and nanotechnology, nanofabrication is critical. Among the required processes for nanofabrication, lithography is one of core issues. Although conventional photolithography with recent remarkable improvement has contributed to the industry during the past few decades, fabrication of 3-dimensional (3D) nanostructure is still challenging. In this review, we summarize recent advances for the construction of 3D nanostructures by unconventional lithography and the combination of two top-down approaches or top-down and bottom-up approaches. We believe that the 3D hierarchical nanostructures described here will have a broad range of applications having adaptable levels of functional integration of precisely controlled nanoarchitectures that are required by not only academia, but also industry

A study on modeling nitrogen dioxide concentrations using land-use regression and conventionally used exposure assessment methods

The land-use regression (LUR) approach to estimate the levels of ambient air pollutants is becoming popular due to its high validity in predicting small-area variations. However, only a few studies have been conducted in Asian countries, and much less research has been conducted on comparing the performances and applied estimates of different exposure assessments including LUR. The main objectives of the current study were to conduct nitrogen dioxide (NO2) exposure assessment with four methods including LUR in the Republic of Korea, to compare the model performances, and to estimate the empirical NO2 exposures of a cohort. The study population was defined as the year 2010 participants of a government-supported cohort established for bio-monitoring in Ulsan, Republic of Korea. The annual ambient NO2 exposures of the 969 study participants were estimated with LUR, nearest station, inverse distance weighting, and ordinary kriging. Modeling was based on the annual NO2 average, traffic-related data, land-use data, and altitude of the 13 regularly monitored stations. The final LUR model indicated that area of transportation, distance to residential area, and area of wetland were important predictors of NO2. The LUR model explained 85.8% of the variation observed in the 13 monitoring stations of the year 2009. The LUR model outperformed the others based on leave-one out cross-validation comparing the correlations and root-mean square error. All NO2 estimates ranged from 11.3–18.0 ppb, with that of LUR having the widest range. The NO2 exposure levels of the residents differed by demographics. However, the average was below the national annual guidelines of the Republic of Korea (30 ppb). The LUR models showed high performances in an industrial city in the Republic of Korea, despite the small sample size and limited data. Our findings suggest that the LUR method may be useful in similar settings in Asian countries where the target region is small and availability of data is low

Anti-Inflammatory Effects of Bangpungtongsung-San, a Traditional Herbal Prescription

Bangpungtongsung-san (BPTS), a traditional oriental herbal prescription, is widely used for expelling wind, draining heat, and providing general improvement to the immune system. In this study, we investigated the effects of BPTS on induction of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), proinflammatory cytokines, nuclear factor-kappa B (NF-κB), and mitogen-activated protein kinases (MAPKs) in lipopolysaccharide- (LPS- ) stimulated Raw 264.7 cells, and on paw edema in rats. At concentrations of 0.5, 0.75, and 1 mg/mL, treatment with BPTS inhibited levels of expression of LPS-induced NF-κB and MAPKs (ERK, JNK, and p38) as well as production of proinflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) by LPS. These results suggest that BPTS may exert anti-inflammatory effects via reduction of proinflammatory mediators, including NO, PGE2, TNF-α, and IL-6 through suppression of the signaling pathways of NF-κB and MAPKs in LPS-induced macrophages. In addition, using the carrageenan-induced paw edema assay, an antiedema effect of BPTS was observed in rats. These findings may provide scientific evidence validating the use of BPTS in treatment of patients with heat syndrome in Korean oriental medicine